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1. 11 13 Test Setup Determining the Reference Point 11 13 Test Setup The Driving Point Survey eeeeeesesss 11 14 Fixturing Boundary Conditions esee 11 15 setting Up the Analyzer ocio steer eot ex Pepe a ed dote aco rha odios 11 15 Setting up the Model 2900B for Modal Testing 11 16 setting up the Model 2900B 3 ELO eta tea TE ve T 11 16 Acousuc Intensity ci 12 1 Why Use ACOUSHC Tnfenslby 7 arte tada ode iens 12 1 Sound Pressure versus Sound Power cccccceccceeceeeeeeeeeeeeees 12 1 Sound Power ATIalOPy ci e 12 2 Acoustic Intensity What 18 IUT sese 12 2 Advantages of Acoustic Intensity esse eee 12 2 Acoustic Intensity measurement hardware sss 12 3 Acoustic Intensity nuts amp DOIS 12 4 Time DOM ida ic 12 4 Erequene Doma dais 12 5 Measuring Sound Power sss 12 5 Sound Pressure Method atar 12 6 Sound Power Setup using the Sound Pressure Method 12 6 Sound Power Calculation for Hemi Anechoic 12 7 Sound Pressure Method pros and cons suuusse 12 7 Why Use Acoustic Intensity As eoo erster dia 12 8 The Acoustic Intensity Probe esse eee 12 8 Intensity Probe Spacer Selection eee 12 9 Spacer Errors High Frequency esses 12 9 Intensity Probe Directivity Pattern sss sss 12 10 290
2. 3 u 43 43 83 T REAL Hote PULSE SIGHAL B4 5 EN BR DR INN o EOLIHT FEPEAT 1 Dual LINEAR 1Hz 2BkHz IME 46 1 T1ime s 1 664 E 06E JS ee De a ITI Base Freauenc y Al ARR I i TACH 8 8 SPEED 46 6 C 565 xs aR RIO RR a BB AAAH ZO00M 1 153 9218 E A solid crar INITIAL A series of either positive or negative pulses can be gener ated from this menu The status of the generator is indi cated briefly by a message on the upper right of the screen whenever one of the keys is pressed The key POS NEG B will toggle the polarity between positive and neg ative going pulses as indicated on the upper right of the screen The time increment for which the pulse is Positive or Negative in milliseconds is set by pressing Ton C entering a value using the numeric keypad and pressing ENTER The time increment for which the pulse is to have a zero value in milliseconds is set by pressing T off C entering a value using the numeric keypad and pressing ENTER The LEVEL E key is used to set the output in the same manner as explained in the preceding sections Selecting Analog Input Filters The analyzer has the capability of adding High Pass and Low Pass analog filters to the Spectrum to cutoff any unwanted fre quencies without limiting the bandwidth of the instrument 1 Press the INPUT K key from the System menu l 16 88 17 Chanls SLM H STAMNDED CROSS INTENSY UNI
3. 1 10ct A 1 3oct B long F short G 2 6 For octave band analysis Note designation in right hand corner 1 a 16 33 16 1 Soct lona short reverse SPL 4 8258 A EXPONENT IAL 1 2 Dual LINEAR 2BHz 2BkHz STOP 13 FEB 38 16 50 ooo SAEREBEEBEEENENUUU FILTER 415 31 5 Hz Channel 1 of 2 HOR d 36 5 A 33 6 TACH Ha SPEED B d de au Hz IMITIAL 1Baline 2001 ine 4qmaline sac ine FFTZOOM WIMDUN BASE Ed For one third octave band analysis 1 BB 16 34 35 leloct lona short reverse SFL 7 23250 EB L EXPONENTIAL LIHEAR 28hz Ek Hz STOP 19 FEB 98 16 33 58 g E A OA o FILTER 14 75 Q Hz Lera Channel 1 of Z HORMAL d A 46 5 DIFF Ph 67 3 Sn 6 53 TACH Ha SPEED B d REM de au Hm E Hz IHITIAL 1991 1 ne 2001 ine 4qmaline saline FFTz DM WIMDUN BASE Bd 2 Press either the long F short G reverse H key to select the type of digital filter algorithm used Satisfies the ANSI 51 11 1986 requirements for Type 0 AA classi fication with optimal passband flatness and stopband rejection This is used more for measuring steady state noise because of the better resolution due to the steep filter skirts EE 16237824 l amp loct 1 3oct short reverse SPL 21 6758 EXPOHEMTIAL 5 1 Bat STEER gta ak FILTER 14 25 6 Hz UE Channel 1 of 2 HOR d H 15 4 DIFF Ph 182 1 sn 74 44 TACH H a SPEED B a ae 138 zh z z IHITIHL 169 1 1 ne 290 1 1ne 46
4. Shaker Excitation 11 SEP 11 53 28 H SPELT C SPECT FER COHER TIME DISPLAY note DETECTR REAL Hotel HO EXP WINDOW LEF Ad Be Y l Lagra a ae c I a a ee Ga oan A COUNT SINGLE DIRECT LIHEAR 1 3 2kHz RESET 11 SEP 92 11 63 38 Fi NEL 00 2 NIC r Tal TIME 46 Hoaas RSBH laiahted Time d 1 568 E H2 REAL Br mH HE hid o My Pr etum iron A ae ae Base Fresu encu LOC TACH 4 6 SPEED B BH HHAH gbb0N _ 1 319 659 E A daotted crar MISC ALTERH BWHORM P gt R ALIAS T TRIG SETUP FILES AUTOSTR 11 inr 11 47 51 H SPECT C SPECT amp FEEK COHER TIME DISPLAY note DETECTR MAG ote GS LEF Ad COUNT SIMGLE 4 DIFECT LINEAR 1 3 2kHz ESE 11 SEP 22 16 5 REL 442 158 r5Hz FSAA 1H MAGHITUBE zZ Base Freauency ee TACH 9 9 SPEED B dB Oh D datted crese MISC ALTERH BlWwHORM PER ALIA TRIG SETUP FILES AUTOSTR e Advantages Shakers normally provide more accurate results Actual test time is significantly reduced Shakers provide more energy to larger structures Shakers can be driven by a variety of signals sine swept sine random etc which provides flexibility e Disadvantages Requires more equipment and setup time Shakers not generally transportable not convenient for field measurements Shaker systems tend to be expensive 11 11 2900B TRAINING MANUAL Shaker Test Schematic elastic cables amplifier N TEE to channel 1 accelerometer PA to channel ERN
5. fix the accelerometer at one point and move the hammer fixed response e Fixed response is preferred e Once you select a method fixed response or fixed excitation you must adhere to it e The reference point is determined by performing a driving point survey Test Setup The Driving Point Survey 11 14 e Driving point measurements are Frequency Response Func tions in which the force impulse hammer and the resulting response accelerometer have been measured at the same location and axis e The driving point survey is used to find the reference point that excites all of the modes of interest e Used to avoid the mistake of performing an entire modal test with the reference point on a nodal line LZ d l 59 42 ALSPECT C SPECT amp FEFE COHER TIME DISPLAY note DETECTE Hate DRIVING POINT GS LEF Gd Lb E T eM 2 2 COUNT SINGLE 4 PREHMP LIHEBR 1 3 2kHz RESET 82 JAN 29 4 56 14 A J FREG Bn AAAAHZ ESRB Transfer Function Hi d 8 58 MAGHI TUDE Base Fresuerncy TACH BH SPEED tted a hdo crar TEIG SETUP FILES AUTOSTR ALIAS JUMS HLTERH EBEWHORH Pa gt R 12 SEP 18 88 22 ASPECT C SPECT amp FEE COHER TIME DISPLAY note DETECTE Hate DRIUIMG POIHT GS LEF COUNT SINGLE PREAMP LIHEBHFE 1 3 kHz RESET z JAH 96 44150114 HB ARBBHz ESHA T1r ansfer Function Hi D 2 d mi PHASE Base Freauenca Sa TACH 6 8 SPEED 4 4 Be AGE gbOM _ 1 1256
6. 1 Connect the printer to the printer port on the right side of the analyzer 2 Press the PRINT hardkey PRINT 3 Press the TYPE G key to select the type of printer being W used The analyzer has a list of printer drivers ranging from G Epson compatibles to HP Laserjet printers 16 FEB 23 48 55 screen table all video LOGO List SPL 9 9090 a EE WAP A a ai O I E LS EXPOHENTIAL 1 8 Dual LINEAR zBHz zBkHz RESET 16 FEB 93 23 47 33 rar JI FILTER 14 75 8 Hz Leo j Auto Spectrum B d 24 3 B 39 1 SH WEG eg IL LI XL ii ondo R ae eee SED ME I TRCH 8 a PEED B a ST RH dotted crer DODFLIS user SETUPS EDIT eject init 6 1 2900B TRAINING MANUAL 4 Highlight the desired printer driver and press the EXIT hard key EXIT a4 HOW BB ote TEST 1 Cannon BJ 43 3004 Diconix 1 j ONENTIAL 1 4 8 Diconix 1 26 dri HRERMP LINEAR 28 2BkHz Dicari J J JESET 64 HOW 94 095 255 92 E iz HILTER 14 25 6 Hz LS Channel 1 of z Er Hs 69 1 LOC 8 09 SPEED 4 8 Printer IMITIAL FAST 5 Press the init O to initialize the printer If the printer was hooked up to the analyzer when it booted up the initializa tion is performed as part of the boot up procedure dicii E TN ee SEMEN CAS VES SPL 9 9090 GIS E EA IO I 12 A E EE P T EXPOHENTIAL 18 Dual LINEAR zBHz zBakHz RESET 16 FEB 93 23 47 33 rar o FILTER 14 25 4 Hz Leo Auto SrEectrum i d 24 3 Ee 39 1 SH PE geese e IE A dr ci udi EE Ra
7. a z z E dot ved i ROOMS ROOMS usREFHM STHT Mx 5rec F TEIG SETUF FILES CRUTOSTR As mentioned earlier reverberation time measurements are acquired with the RTA using the Autostore feature 9 To enable Autostore press byTIME B zh B 13 35 43 OFF ba T LE Jdelta endstor note SPL Eire TH r E A A A A A A e a He LIHEAR FEFEAT BH Em bT IE Dual LIHEHR 26Hz 16kHz RESET 246 FEB 98 13 31 27 SH r RR RR RR RR NN FILTER 14 25 4 Hz Sri Channel 1 of 2 HORMAL d E B 23 4 AB r RN O RR AA a et RR ua 9 DIFF Fh Za 1 n d SED TACH 9 9 SPEED B d datted crar s Z z z ROOMS baTACH TACHSET F TRIG FILES Notice that the label bTIME appears on the left side of the display zh FEE 13 35 43 OFF ba T LE delta endstor note SPL B GRE Q RN ohon oh m hok n mon n n m nomo on a m n n n m n n n n n LINEAR FEPEAT A BSA bTIME Dual LIHEBR 26Hz 14kHz RESET 2H FEB 98 13 31 27 54 KNN RR A OR AA N RR RN NN RR E A RN NN NR FILTER 14 25 8 Hz m4 Channel 1 of 2 HORMAL d B B 73 8 AB A LL Ls an pense ed opoe a R asta Sp ecb EE RER E R RE DIFF Pbs ZA 1 Ens z 44 REM lt TACH 4 8 SPEED HL dotted crar FILES s Z z z ROOMS baTACH TACHSET F TRIG You now need to establish the Autostore endstore duration and the Autostore delta The endstore is the amount of time that is allocated for the total reverberation time measure ment 3 to 4 seconds is usually more than sufficient for most room
8. IDEE Rr TD Tm DIFF Ph 96 4 zns 232 18 PEN n TACH BH SPEED Ae z Bok Hz S recall data ROOMS DELETE A Preu HB Hext Continue pressing the right or left arrow hard key to page back and forth through the individual spectra You will now use the vsTIME feature of the RTA to see how spe cific frequencies changed in amplitude during the 2 second Autostore measurement 5 Press CURSOR to activate the dotted cursor Then use the right or left arrow hard key to a desired frequency value such as 1 25 kHz To view how the 1 25 KHz band changed during the 2 0 sec ond Autostore measurement press VSTIME E zH a 15 89 49 W Fall E RUE E MAK E SUM vsTIME KEEP Hate SPL 1 868 PU lea cce PD LETT LIHEAR FEPEAT 8 8558 bTIME N Dual LIHEHE 26Hz 16kHz STOP z FEB 98 13 86 67 20l LL FILTER 26 400 Hz 5 2 MELLE 1 of 2 PORMAL A T E DIFF Ph 96 4 Sm 232 18 SED TACH H H SPEED B d recall data Z eod Hz E ROOMS DELETE A Prey A Hext Notice that the horizontal scale of the measurement display has changed to time with values of 0 5 to 2 0 seconds on either end You can see how much acoustic energy the room experienced when the pink noise generator was on and how the reflective sound was absorbed after it was shut off The time between when the noise generator was on to the ambi ent noise level of the room no pink noise is a measure of the reverberation time zH FEB 15 15 16 ETE REPLACE AVERAGE Auto
9. RESET Hr JAN 95 20 46 83 ro a A FREQ Ae ARARAHZ ESHH Auto Sreectrum D 1 d HB B a 23 56 B PLATEA A Wie Wm EEE RR R K RR BAS RE E Pm Base Fresuenc y Ae BRB REM TACH H B SPEED B B t E E dotted crar HLTERH ElHOF FEE SETUP FILES AUTOSTR 11 23 2900B TRAINING MANUAL 31 Next select a trigger level as a percentage of full range by m pressing LEVEL M M um zH 4y y 4d5 H SPECT TIME nate LEF lar RR AA A SA O A A A A A Goa can O ei MANUAL ACCEPT EHE iHz 18kH z RESET ar JAN 93 295 d75 29 ro I AGED lai cuit far viet e E SEA ge a FRE He HRREHS ESRH Auto Spectrum g 11 3 E B QM sey cx HE Jae SERO Wate sae OEC E ied ES R oa dl etr HE EN E E CD etn dorus Rua de Baze Freauercy aA APAA Tunt td He Chz He sau TACH 6 6 SPEED a d de DUZ dotted crar IHITIH HLTEEH EBlJHCOEEP FEE DELAY 2 DELAY OFF 32 Use the right arrow hard key to increment the trigger level 10 for example The trigger level can be viewed on the lower left portion of the 2900B set up summary on the right hand side of the display screen Note positive indicates a positive trigger level negative indicates a negative trigger level 33 Next check that the analyzer is set up to trigger on a positive slope This can be verified by the arrow next to the trigger L level An arrow pointing upward indicates positive slope while an arrow pointing downward indicates a negative slope The slope can b
10. ai Ar MEME TNR IET RETENIR RO NR FILTER 1 75 L Channel 1 of 2 HORMAL d 34 4 a 49 2 Behr Ld Ic A TN BIFF Fh 55 a n E AS SER l TACH HLH SPEED B El 25 5 Hz Bae Hz ZH HE HZ datted crar IHITIHL 3 Press either the YES A key or the NO C key 20 DER 18 55 37 WES HO ARE YOU SURE i 6 90069 146 r R N NN AMD o EA Car ME sd R S a AD MP NITE N RR as URP LR IC ly Aen UL A AN A A o E EXPOHENTIAL 1 Dual LIHEAR ZBHz l8kHz RESET SE zn a se 46 Bh S NNN N alan o a NAR yet Jie rs alpine an ao vias cee ret at de NN aa aa cay vera cat Jade a dp EV see FILTER 1 75 Channel 1 of Z HORMAL d 34 4 B 49 27 eh r CHA N ose A XO EI ere e REP HU dece e A OD ONDE DES UR De Same a C NC R D 7 8 BIFF Fh 55 a n E AS REM l TACH HL SPEED B El 25 4 Hz amp 3H Hz 206 HE HZ dotted crar IHITIHL The RESET will be performed if you press the YES key If you press the NO key the RESET will not be performed and you will be returned to the Reset menu 4 Press the EXIT hardkey to return to the System Menu 2900B TRAINING MANUAL 2 32 Shift Menu Defining a reference spectrum SHIFT In some applications it is desirable to compare two spectra or to display spectra relative to some user defined spectrum The spectrum which is to be defined as the reference spectrum must first be displayed on the analyzer In most cases this would be a spectrum that has been stored to the memory of the
11. de Channel 1 S Z ST SH i hay ke Sw NA DIFF Phz ao z n zH AS REM TACH 9 9 SPEED Bg d H Hz Bak Hz A kHz ated crzrm DUUE UZ McSTOP McWAIT McREPT McSTHET SameFER SetEE Ls REF The spectrum will be placed to zero across all frequency bands and the vsRef indicator will appear on the upper left side of the display ad rig 2ordrids HORPMBHL Les MIH MAM SEL DISPLAY note DETECTA Hote TEST 1 SPL 7 7259 GL HHE SH 1 79 i D LIHEHE 26Hz 29 HZ FESET 64 OCT 94 23 39 47 TS SRS N T EST TTT 15T INN CNC UIT RETE Z FILTER H 1 15 Hz L A Channel 1 of z HOPAL d PH HS 98 4 TACH B B SPEED B a S z H Hz datted crar IHITIHL ROOMS WeRPM STAT Mx EC F TEIG SETUF FILES AUTOSTR 3 Press the R S key Note that how the current data are being RESET compared to the reference spectrum If the data in any of the R S frequency bands are greater than that of the reference spec trum the level will be above the 00 db line If the data in any of the frequency bands is less than the reference spec trum the level will be below the 00 reference line Za E 26 23 06 NORMAL Lex NIH MAH SEL DISPLAY note DETECTE Hote usREF SPL 3 4758 2H r Nr R N a Mat aOR ol sio fan ci uy e Me A vie a T GD fave cays itv e AN Gen 1 T cor fae A E cia zB g H DIFF Ph 68 5 sn r z1 TACH BH SPEED B a LIHEHE ZzEHz zEkHz STOP 23 FEB 9S 20122116 r 5505 eee ee 09 222222 o or nz n Bl nn nhBgzg FILTER 14 z5 IS Hz
12. e Self Induced Vibration Impact Hammer e Advantages Easy set up Easy to make measurements Inexpensive Field portable 11 5 2900B TRAINING MANUAL e Disadvantages Large amplitude on the impulse can cause non linear behavior Difficult to excite large structures especially at distances far from the impact point Time Domain and Frequency Domain Signals TACH 4 46 SPEED a A Bd BINE Hl dotted crar SMSBEA ALTERH BlWwHORM PZ gt R TRIG SETUP FILES AUTOSTR 43 SEP 18 15 53 A SPECT C SPECT FER COHER TIME DISPLAY note DETECTE 1 So aaa xe TON aris R WI RP IHE QR REI ID BOUE E cil eat LP CO EE ENO Ras DC uie cH He E eu E nte RERL Hate 2X LEF ad DG PE fag las ate hese we ODS HPL OS BCE quies RA mcus ene Ss COUNT S INGLE 4 DIRECT LINEAR 1 3 2kHz l RESET G1 JAW 98 Ba 24 13 Ba puc erue a uie EIU Oen TIME 34 6255 ESHA l lleishted_Time D 1 d 5 677 E 39E Hr n n nnn n 1 so Base Fr eaAuenc a4 LOC TACH 4 4 SPEED mB B a a ed crar Bi 6000 Z00M 1 159 6875 E B datted c SMSEEAM ALTERH BWHORM P lt oR ALIAS T TRIG SETUP FILES AUTOSTR S SEP 18 17 36 A SPECT C SPECT X FER COHER TIME DISPLAY note DETECTR REAL Hote 1 Y LEF COUHT SINGLE DIRECT L THEHR 1 3 2kHz RESET 6i JAN 96 695 245 1 2 TIME 34 H amp z5m 5 ESHH llaishted Time D 1 d 5 456 E Bd4z Base Freuuencu ad Loc TACH 8 8 SPEED 4 4 BB 06nd FooM i datted crar SMSB
13. 0 31 mv ft s 7 19 2900B TRAINING MANUAL RESET 7 20 EXIT R S 11 Note that the integral of ft sec will be ft s Press mv cal F to change the calibration value B3 tet BEE 325 41 SLOFE name SAME R UHITS Hoize F D U cal level ETS E bebe TH Erw e PE Qe oe cer aah ue ete Soir cm ints cat tu Sup Qe er See Sah A O hap OR UP ML dE a deb veut cas say Sp Nee ies AED Im LIHEHFE STHGLE zH Em Inrut LIMEHR 1Hz iBkHz E H i JAN 98 965 3 25 2 SH AG he Se aes A A R RT A NN R A ie ME ewe 111702172071 FREQ QG AHHGHZ HSHH zene 1 of 1 HORMAL A o o eee bees need dae oe eee eo Ge ea eh oe eels BEM a TACH 9 9 SPEED B d gi E solid crear IHITIHL dB vU SPL G ETS under under under Under 12 Next type 000310 using the alpha keys on the keypad to enter the new sensitivity number Then press EXIT to enter the value Press EXIT 2 more times to return to the main menu LIHE K Ineut 1 LINERE i1Hz EESET d APR 94 16 55 FREQ Eg BBBBHz H Channel 1 of 1 HORMA s 113 1 E 85 8 l l TACH B B SPEED B a solid crear If a shaker calibrator was used to calibrate the RTA the same method as was outlined earlier in this note would be used In this case when the level of the shaker signal is entered it must be in ft s For our example a 1 0 8rms shaker was used Since 1 0 g equals 32 2 ft s this would be the calibra tor reference level Follow the procedure that was previously outl
14. TEM hardkey Microphone calibration CH1 RESET R S Next perform an amplitude calibration for the two probe micro phones To do this first loosen the microphone fixture on the probe so that the microphones can be separated Remove the spacer Next insert the channel one microphone into the open ing of your Larson Davis CAL200 or CAL250 calibrator or any other SPL calibrator you have 1 Press the CH1 hard key to display channel one Turn the cali brator on then press R S to begin a measurement Adjust the input range up or down using the up or down arrow hard keys until the gain level is optimized One way to do this is to press the down arrow until an overload occurs Then press the up arrow one or two steps 12 15 2900B TRAINING MANUAL RESET R S CURSOR EXIT RESET R S RESET R S 12 16 T Press CURSOR and then move the dotted cursor to the cur sor band within which the calibration tone resides 250 Hz for the CA250 calibrator Press R S to stop the measure ment Press UNITS F I 20 23 45 Chanls SLM A STANDRD CROSS miae UNITS FILTER CLASS SPL 3 5588 ab uec 111117 7010111715071 2110717 0710710 ERXF HEHT HL 178 Dual LIMEHR 26Hz 16kHz STOP 12 JAH 398 26 23 61 TH cUm ds x P FILTER 24 z254 Hz Leo Channel 1 of 2 HORMAL d 161 1 A SH a A noe cae ab ae Sate ele uA Se Sele O DIFF Fh 91 6 n KIZ RES TACH Ha SPEED B d x z z S dotted crar INITIAL 1 0 SIG GEH IN
15. dEnm s 26 mma dE JOB 5 TEST FEM FART FRONT A Mey tee Meher A RE RC Seah Sey ah cals ok Guna RR RE AREA POINT H Hz z ZEA dotted crar HITEST area Pree se S SE TUF FILES AUTOSTA Press QUALITY C to view the Quality Indicator Function measurement 13 ie BEI Sai se POWER MC SPL F WELOC DISPLAY note DETECTE Hate rdEa3ual zB m MM IP CM mm ror LIHEHFE SIWNGL 7H Ge Dual LIMEHR 26Hz 16kHz STOP 13 JAH 98 Besa 14 RA RR E THT oS FILTER 24 z254 Hz Leo we QUALITY 1 d 13 8mm 1 9 dE 7H E Sa GL NC NOE o aT oui cae RE UN MM BC BEEN a 0 A E E Aer AG JOB 5 TEST FEM FART FRONT EX HI AREAS PO L NT 1 dotted crar netera SETUP FILES AUTOSTR H Hz AITEST Job area phy beer In general the Quality should be between 0 and 10 dB no greater than 15 dB for the measurement to be deemed acceptable 2900B TRAINING MANUAL EXIT RESET R S 6 If you wish to continue the sound power survey first store this initial measurement to RAM by pressing KEY B on the probe or the STORE hard key Before beginning the next measurement change the name of the area by pressing area K 13 JAN BES A55 z2 POWER INTHSTY QUALITY SPL F UELOC DISPLAY note DETECTR i Hate dEaual ZD ARE PO rnnt LIHEAR SIMGLE 7A 9002 Cual LIHEHR 2B8Hz lBkHz STOP 13 JAW 93 29 325 17 14 ee ee ee aaa ee ee a ee A a o FILTER 24 254 Hz Les we QUALITY 1 d 13 6mm 1 9 de 2H e cp A UN MET P e L R
16. 31 1 25k HZ L E TEIG i Channel 1 of HORMAL d 3 1rE B1 A 2 61E h2 rel ia chat dul ei vw ded RESO LC ie ia ake Gate Te ae o PRISE OS A pees FREE Fh 66 4 n 5 PEM i i TACH Ha SPEED a d ES ias m l dotted_ crar DUUE UZ 1 0 SIG GEH INPUT clock COLOR MLS FILES RESET S To achieve an accurate battery level reading you may need to perform this sequence more than one time CHAPTER Basic Acoustics MEASURING SOUND microphone preamplifier power supply instrument slm analyzer chart recorder tape recorder etc Basic Acoustics LS BASIC ACOUSTICS MEASUREMENTS Determine what type of measurements is to be made free field diffuse field s Choose the correct microphone for the measurement free field random incidence Position operator correctly Basic coustics 4 1 2900B TRAINING MANUAL LS MEASUREMENT TYPE Free field measurement outdoor anechoic chamber no reflective objects in field sound is absorbed by the environment Basic Acoustics LS MEASUREMENT TYPE CONT Diffuse field Gymnasium Warehouse Shower contains hard or reflective surfaces Basic Acoustics 4 2 2900B TRAINING MANUAL D MICROPHONE SENSITIVITY The quieter the sound level the more sensitive the microphone must be Conversely the louder the sound level the less sensitive the microphone need be Applications requiring measurements of very
17. 6606 A dotted_crsr SMSBEAM HLTERHM BWHORM Perk ALIAS T TRIG SETUP FILES AUTOSTR 2900B TRAINING MANUAL i S 18 81 15 A SPECT C SPECT AFER REAL LOC 1 BA ARE ZO0M 1 SMSBEAM ALTERH BWwHORM PER te ze 18 81 41 A SPECT C SPFECT FER IMAG Loc 1 a8 He BABA ZO0M 1 SMSBEAM HLTERH BwHORM PER Fixturing Boundary Conditions 1250 6064 2 B do T TRIG SETUP FILES AUTOSTA TIME DISPLAY note DETECTE Hote DRIVING F IHT GS LEF Ad COUNT SIHGLE 4 PREAMP LIHEAR 1 3 2kHz RESET Hz JAH 9H 84 56 14 i 66 B6B Hz ESHA Transfer Function H1 D 2 d 1 852 E 41 FEAL Base Fresuency TACH B B SPEED B n Lted crar TIME DISPLAY note DETECTE Hote DRIVING POINT GS L ad 56114 E BGOOOHZ ESAA Transfer Function H1 D 2 d 5 87f E 33 IMAGINARY Base Fresuency TACH a a SPEED a d EM Hatted crar TEIG SETUF FILES AUTOSTE e Structures can be tested in free or constrained boundary con ditions e If you are testing the structure in a free free boundary condi tion the structure can be suspended from soft elastic cords or rested on soft foam e The highest rigid body mode frequency should be less than one tenth the frequency of the first structural mode e If you are using constrained boundary conditions you must make sure that the constraining system s dynamic properties do not affect the dynamics of the test item Setting Up the Analyzer e Set the
18. A A A A GG ah FILTER 14 E IS Hz SS vi Channel 1 a z o is 68 EE DIFF Ph 65 9 5nz i 6 05 REH AE l TACH H H SPEED B El 2 z A dotted crar ROOMS 12 Choose an averaging time 20 seconds for example by first pressing AV TIME H mE 10 05 64 LIH S LIH F EXP BT EXF ET LIH Al TIME E SPL B aaga 155 r A A A RR RR NN RN R tote LIHEHFE STHGLE A 25564 Dual LIHEHRE 2BHz Z6k Hz RESET 23 FEB 38 10 64 36 SH EOR O k NR RR RR O A a et ois ar R ie FILTER 14 zh Q Hz Leo Vs Channel 1 E Z T 6B K Samaa CTPREPCPTCICD MITT BIFF Phz 65 9 Sh 6 65 REM l TACH 9 9 SPEED B B z z z z dotted crar ROOMS EXIT SCREEN SYSTEM 2900B TRAINING MANUAL 13 Enter 20 seconds by typing in the value shown in the follow ing graph 23 FEB 10 06 54 126 DETECTOR TIME lalola BEY 146 E A AA E A RR cae ate R A LIHEHE SINGLE B SB i Dual LINEAR 28Hz ZBkHz RESET 23 EL 10 64 36 ai pcr Axa MEISTE FILTER 14 Hz L 3 i E Channel 1 SL z HORNAL EO L DIFF Ph 65 9 Sm 6 85 REM gi l TACH 0 6 SPEED Bg d z z s dotted crar ROOMS 14 Press the EXIT to enter the 20 second averaging time and then press SYSTEM to return to the System Menu You are now ready to make a measurement you ll start with the source room sound pressure measurement Again using the pink noise generator of the 2900B with a speaker amplifier is the ideal way to make this measurement Place the speaker in a corner of the source room
19. C FREBLIEHC et J MATA moo Bese Odor HT a LAS JO ET EIN A SIS SIS SIS SIS SIS Be Bi JB DCMOTOR You are now ready to make the measurement Notice that the FREQUENCY column on the right side of the display has changed to ORDER The measurement is currently set up to do a live display of orders 1 through 6 If you would prefer to look at different orders you can change the order number as shown in the earlier section vsRPM Graphics Once again check that the output of the tachometer is con nected to the TACH INPUT jack of the Model 2900 Also check that the accelerometer is connected to the Channel 1 RESET R S RESET R S 2900B TRAINING MANUAL input Make sure that your tachometer is turned on and is reading an accurate tach signal from the rotating test item that is below the beginning of our X SPAN 500 RPM Press R S to initiae the measurement Notice that since the RPM of the tachometer signal is below 500 nothing appears on the display although you can see the trace labels on the left side Note the current RPM reading from the tachometer is displayed on the lower right side of the display 16 SET 18 44 59 SLOFE elevel TAGERES SPAM WIDEO ARIS note WIDTH SOURCE IS TACH IHPLT 22 2408 7H Bode aca a Se Cee Gerd R a GA ae A te Gee ra ee a oh cae ra A EA EXPOWEWT IAL 1 64 Ht te GEES pee ae 4A rd ae neh a cis Ba ae a cp A ee A E da ee RT apn nee as E T FEH ELEL C ORDER
20. Channel 1 of 2 HORMAL d x Ee 56 5 z80 l eeo IIA in Nm PHONES 64 4 Sne TACH H H SPEED BH B s ET E Er E Trigger IMITIAL MANUAL FE ARM OFF leue l b Press either the Left or Right horizontal arrow keys to select the desired trigger frequency By pressing the arrow keys you can page forward and backward through the available fre quency range as indicated by the changing value on the display See figure below l gt H 22 860 Hz 4828 8 PL B3 OCT 15 27 46 ga 5 14 56654 TH EEE Sa Rs ra A ATR a EMR wc e d wo M 6 R ec De des A A d dE Rum 9 AAA aro EXPONENTIAL 1 75 Dual LINEAR 2AHz Z6k Hz STOP mi OCT 94 15 25 56 54 ee Be a se a a exo a m sue ee a ee a X ED del Um Sa KS A ea Um ee Da FILTER 4 1 BST Hz L 3 TRIG Channel 1 of 2 HORMAL d 16 4 E 56 5 zB leee IA ies Nu PHONES amp 4 4 sia TACH H H SPEED B d z Trisaer INITIAL MANUAL RE ARM OFF level 2900B TRAINING MANUAL EXIT RESET R S One step beyond the highest available frequency band you will find Spectrum Y which means that the measurement will trig ger based on the level or slope of the overall level c Press the level P key to input the desired trigger level Upon pressing this key the following message will appear on the upper right of the display 85 OCT 15 29 46 l TRIGGER LEVEL 050 ES EXPONENT IAL 1r Dual LINEAR 28Hz 2BkHz STOP G3 OCT 94 15 25 56 FILTER 1 88 Hz LS Channel 1 of 2 HORMAL d 56 5 PH
21. Hotes ERF HEHTIHL Ineut 1 LIHEHE iHz 16kHz STOP 14 APR 94 15 53 22 FREQ 21 25 6bHz HSHH Channel i of 1 HORMAL d 73 4 E A R TACH 8 8 SPEED 4 4 z LIP pel Srk McSTOP McWAIT McREPT Battery dotted crar SameREF SetREF us REF This feature toggles between linear and log vertical scaling Notice that the vertical scale is now in linear units Hotes 6 6368 EXPONENT IAL a Ineut 1 LINEAR 1Hz 1i kHz STOP 14 APR 94 16 83 27 p 51 2566Hz HAA Channel 1 of HOR r d 4 67E 03 E 4 SBE 43 TACH 6 6 SPEED B dotted crar BOTH SUL LD DOTTED 2900B TRAINING MANUAL 11 Press SYSTEM and then UNITS F to return to the units V menu Press level H F IS APR 16 84 14 SLOPE name SAME R LUHITS Hoise F ml cal U cal evel Hote 6 6368 rad EXPOMENTIAL a Ineut 1 LINEAR 1Hz 1i kHz STOP 14 APR 94 16 83 506 FREQ 51 2566Hz HSRA Channel 1 of 1 HORM d 4 67E 83 E 4 20E 63 zl LOC TACH H a SPEED B E 4 Bn S dotted crsr IHITIHL dE el SPL G ETS undet under Under Under 12 Enter the output level in linear units of your calibrator The EXIT level is entered in engineering notation For this example enter 1 0 gns as 1 000 E00 This will actually be entered as 100000 Then press EXIT 14 APR 16 85 32 1 688 r 3l Es PIN Q Ineut 1 LINEAR TES 16kHz STOP 14 APR 394 16 03 27 JA FREQ 81 25bbHz HAA Channel i of 1 HORMAL d 4 6rE 43 etd SGE HS zl LOC TACH 6
22. K key The Macro that was assigned to key 1 in the previous step Defining Macros will immediately be executed upon pressing the numeric key Storing Macros After defining a marco to one or all of the ten registers 0 9 you may store them as a set of Macros as a file to the memory of the analyzer 1 To do this press the STORE hardkey STORE The message Store Macros Data XX will appear on the upper right side of the display This indicates that the Macros have been stored as a file to the memory of the analyzer and have been assigned a record number xx x ics 15 66 13 Chanls SLM H STANDRE CROSS SPL S H abe RN e MEN cars ulin sat var vg Apnea uae oa fat cae Ra M cay TREE VET NES AN To Nic qup Cn a Gen yaya dee anh ser Mia LINEAR STHGLE 5 AHR Dual LIMEHR 2BHz 26k Hz STOP 23 FEB 98 17 9713 T Wo RT R RT RT s c Ee HER Os e aes Sats Se in came R cas E CREE UC C E N NOUS abc E US OUI C a a E S DGH H4HBA SHEET 1 of Daa TACH 8 8 SPEED B a dh E 001 1 doatted crar DUUE UZ SIG GEH INPUT COLOR MLS FILES RESETS 5 4 CHAPTER Printing The analyzer can print any displayed data directly to an Epson compatible Canon BubbleJet or Hewlett Packard LaserJet printer equipped with graphics capability and a Centronics par allel interface Before printing you will want to make certain that the desired spectrum has been recalled from memory or is currently dis played on the analyzer
23. Lea DISPLAY note DETECTE a set bons deat RAS C E S eia f E CE E T RL O tap 53 757 Z8 Tei E NO HAH SPL 1 7458 TH T cee tas E RA NR RA REE by Be oR aoe oe EXPOWEWT IAL 1 A Dual LINEAR zHHz zBHkHz i STOF 63 OCT 94 14 35 08 54 L pe lw MI E od be esd A E FILTER H 1 NE Hz L 3 Channel 1 of 2 MAXIMUM i d A 56 5 GA O PPP ocx a A a o a A a Me das cals sap tay a PHONS bar 1 LOC TACH BH SPEED a wok Hz 2H H Hz Ld Lic Hz dotted crsr INITIAL ROOMS uzREPM STHT F TEIG SETUF FILES AUTOSTR Displays the averaged spectrum according to the parameters se lected in the Detector H menu Displays a spectrum that represents the steady level which inte grated over a period of time would produce the same energy as the actual signal The period of time is the actual run time of the analyzer Displays the minimum level measured for each filter band since the last reset Displays the maximum level measured for each filter band since the last reset Sound Exposure Level is similar to the Leq except the signal is the equivalent energy if it occurred over a 1 second time period This display type should not be confused with Max D see above Max Spec displays the spectrum corresponding to the highest broadband level that occurred during a measurement 2 After selecting the desired display parameter the analyzer will display your selection on the left side of the display and on the center of the right side See figur
24. On the right hand side of the screen the values for intensity and sound power are listed for each of the 1 3 octave bands for this particular spectra and for the overall summations If you would like to look at the power and intensity values at other specific frequencies 12 25 2900B TRAINING MANUAL CURSOR m c OW 12 26 2 Press the CURSOR hard key then press the left or right arrow key to move the cursor to the various 1 3 octave bands 3 Press SPL D to view the averaged sound pressure level that was measured F UELOC DISPLAY note DETECTE dE 1 Baie MN SIHGLE 26 ai Dual LIMEHR 25Hz l8kHz STOP 13 IHH 923 9 01 39 FILTER 24 258 Hz Les wr IMTEHSIT S 1 d _14 6mm d z PUS 595 6TdB a8l tBBBBgm JOB_ TEST PART FRONT IS KE Sins co o de E E S R AE ERE LP AE ERE EIL AREA PO L NT 1 25 8 Hz JHE Hz 1B8 BkHz A dotted crar HITEST jab Fart area Pr L Sp meter SETUP FILES HUTO STE 13 dap 155 ad 9 2 POWER INTHSTY GLUBLITS SPL P WELOC DISPLAY nate DETECTA I i SPL 26 0664 TH gR cole TN aah RR Gat NN see te ad LIHEHE SIHGLE zu EE Dual LIHEHE 26Hz 16kHz ETOP 13 JAH 98 90 91 32 2i n or or onc o AERIS FILTER 24 z756 Hz Leo me SPL d 13 8mm d 56 2 A 72 8 JOB TEST FEM FART FRONT A NE MM RE AR neta Sal Guna EN M AREA PU INT H Hz z Hl El dotted crar HITEST area Pr L SE mater SETUP FILES AUTOSTR Press P VELOC E to view the Particle Velocity that was measured
25. X ORO NN WX c X EX E X X A X x X x FOX X o X E X X amp x ow R CBUNT MANUAL OCEEPT Dual LIHEHR iHz i1BkHz UH BY JAN 98 21 52 33 ro By Se AO ni dat O SEE A E A A A R RRR me cay RR K EK E cca R FREQ Hi 1z258HBHz ESHH Auto Srectrum D 1 d 38 4 B 60 6 B R KR RR NR RR RR NR RR R N N NR RR RR RRR RR NR NR RRR R R NR RR N N N Base Frey Heng y A EE 2047 Ld zH Ch2 Be REM TACH H B SPEED HL level 5 Lp T TRIG SETUP FILES RUT STR QG E OUZ INITIAL HLTERH EWNROF HA FEE Continue taking averages until you feel you have a success ful transfer function typically 4 to 10 averages should suf fice 11 25 2900B TRAINING MANUAL 38 Then press R S to halt the measurement RESET arian 22 03 30 A SPECT C SPECT FER COHER TIME DISPLAY note DETECTE R S LEF BA aii 2220111017207 1100111111111 72710117 11111711727 27111127 1 COUNT MANUAL ACCEPT STOP Gy JON 98 22 84 23 Pa T la RR A R AE e SEE R GE i AA RE RE alr R RR IE Ha sae eh R a Fa FRE Hi 12556Hz ESHH Auto Srectrum D 1 d 39 6 B 60 4 bal a K KRK RR NR RR K RR KR RR R R R NR RRR RRR RRR R RR N RR R R NN NR R K N Base Fre3suencuaz QG Em riBzt Ld zH Ch2 Be REM TACH BH SPEED HL BE k t dG 27 38 Le level IHITIHL ALTERH BlWwHORM Pe gt R T TRIG SETUP FILES RE 39 You are now viewing the input autospectra for channel one It should look similar to the display above Notice that the CH2 spect
26. dotted crar IHITIH 1 0 HOISE IHFUT clock COLOR SETUP FILES RESETS 15 Press R S to stop the measurement Now disconnect the transducer from the calibrator and then attach it to the test structure from which you wish to acquire vibration measure ments Next let s change the horizontal scaling back to full scale Press SHIFT and H SCALE E to enter the horizontal scale menu AKIS YARIS LU SCALE V OFSET fe cate OFSET EET ZOO T SHH EXPONENTIAL 1 3 Ineut 1 LIHEHE 1Hz 16kHz STOP 14 APR 394 16 08 54 x 81 2 586HHz HSHH Channel 1 of 1 HORMAL dz B d E BH 3 TACH B B SPEED B a oh ey 1 or ok dotted crar Mc STOP ficWAIT McREPT Batters SameREF SetREF Ls REF 16 Change the scale multiplier to 1 by pressing 1 A SELECT Horizontal Scale E T 45868 EXPONENTIAL 14 8 Ineut 1 LIHEHEF 1Hz 1i kHz STOP 14 APR 94 16 11 68 REQ B81 2588Hz HSRA Channel 1 of 1 HORMAL g M1 B ALS TACH 6 8 SPEED 4 4 dotted crsr When possible vibration measurements should be acquired using a linear average over a finite amount of time Averaging will improve the quality of the measurement by negating the contribution of nonlinearities and external random noise Nor mally the longer that you average the better the measurement quality 7 13 2900B TRAINING MANUAL 1 To establish linear averaging press EXIT twice and then choose DETECTR H EXIT 21 MR 10 13 27 NORMAL Le MIN MEX SEL
27. e 1 ee oH za L T E DIFF Phe 91 2 Sm 24 78 REM o TACH H H SPEED Bg d S recall data ROOMS 14 Then press EXIT to enter the selection Notice that the new averaged Autostore record is dis played and is stored as By Time record number 7 Note also that the word AVERAGED appears on the right of the dis play 28 FEE 15 26 24 W Fall B AVE B MAX B SUM usTIME KEEF Hote SPL AVERAGED FO LIHEAR REPEAT B bTIME Gual LIHEHR 26Hz 14kHz RESET 26 FEB 98 15 17 55 Sa FILTER 22 1 B6kHz 5 3 MESI 1 proe a ee r zn DIFF Ph 89 3 Sn 38 65 REM TACH 8 8 SPEED 6 4 H Hz Eod Hz x recall data 005 DELETE H Freu A Next 9 15 2900B TRAINING MANUAL Viewing the RT60 Reverberation Time Values 1 Press CURSOR to activate the horizontal cursor Then move CURSOR the left or right arrow hard key to the 1 6 kHz frequency band 28 a 15 89 49 W Fall EB HUE B MAs B SUM usTIME KEEP Hote SPL 1 8888 ra LINEAR REPEAT B 8588 bTIME i Dual LIHEAR 2bHz 16kHz STOP 28 FEB SS 15 06 07 FILTER 44 E Channel 1 of 2 HORMAL d 65 H DIFF Fh 98 8 Sns 32 16 REM TACH 8 8 SPEED B a s z Bak Hz x hrec all data ROOMS DELETE H Freu A Next 2 To display the 1 6 KHz band decay curve press vSTIME E 20 FER 15 09 49 W Fall B E SUM KEEP D Hotes SPL 1 8868 re LIMEAR REPEAT B dot bT IME Dual LIHEBR 2BHz 1BkHz ETOF 2B FEB 92 13 86 87 FILTER 26 466 Hz 5 3 E Channel 1 aa z FT
28. i E B Bara EXPONENTIAL 5 I E Ineut 1 LIHMEHE 1Hz 1 kHz FESET Hz JAN 98 23 51 23 ro m ds a N RE EL PEE a E FREQ H6 z58dHz HSHH Channel 1 of 1 HORMAL d B d E rad REM TACH 6 6 SPEED a d AA Bel HAHA Z o0m 1 7509 0006 Z A dotted crar IHITIHL 3 Then press EXIT to enter the value Assuming that the sensi tivity value from the transducer paperwork was still valid we would now be calibrated and ready to make vibration measurements Another way to calibrate the RTA is to utilize a shaker calibrat ing device that puts out a known vibration level at a specific fre quency These are manufactured by a number of transducer manufacturers To calibrate the 2900B2800B with an exciter attach the trans ducer firmly to the exciter head The transducer output will go directly into the analyzer or via a power supply depending on the type of transducer and connectors available 7 9 2900B TRAINING MANUAL RESET R S gt gt RESET R S 7 10 lt lt 4 The calibrator that is being used for this example outputs a signal of 1 0 g as at 81 25 Hz Turn on the calibrator Press RS to run the RTA The 81 25 Hz calibration signal will appear in the measurement display z1 HOR 935 155 2 2 SLOPE name SAME E LUHITS Hoise F mi cal U cal level 86 2 cal si EXPONENTIBL ae 1888 car signa Input 1 LINEBR 1Hz 1GkHz EUM 21 MAR 94 08 14 43 FREG BB 4808H2 HEAR Channel 1 of 1 HORMA
29. l 2 1 Cm 2 BH2 45 2 1 B2 BEE 5H4 nuaa E 3 AS 48 z 1 AS Bad d Bi 51 3 1 Bd mad LOC B B5 31 3 1 E15 maa 24 boe obuka O AA ET RR EAN A NA Bin RRR e Ee 5 Hg 51 3 1 DG ARR 3686 RPM lt 286 cresr 181 DCHOTOF STATUS HIDE TACHSET E FREL CAL PEH CHRHHEL ORDER Now as you sweep up the running speed of the de motor you can watch as the selected orders change in amplitude as you run up from 500 RPM to 3000 RPM 16 pe 18 46 14 SLOPE a alewel TAGBARS amp s SEHHM VIDEO ATAR IS note WIDTH SOURCE IS TACH IHPLIT 22 428688 EXPOMENTIAL 1 64 Input 1 LIHEBR 1Hz 1B8kHz RUH 16 OCT 94 18 44 36 FEH LEVEL C ORDER K i 3 3 1 61 000 2 H2 3 5 1 Bz aae 3 Hi 16 7 1 B3 aaa 4 q 36 2 1 Ba aaa 3 4g 42 3 1 B3 aaa 6 B amp 32 8 1 Be aaa 306 3866 RPM 2597 crsr 5d4 DCMOTOR STATUS HIDE TACHSET B FREB CAL FEH CHANNEL ORDER When the speed of the motor reaches 3000 RPM press R S to halt the measurement The completed measurement appears below 16 oa 18 46 56 SLOPE elevel TAGERES SPAM VIDEO ARIS note WIDTH SOURCE IS TACH IHPLUT E l r 6688 APOMEHTIAL 164 neut 1 LIMEBR 1H2 16kHz Br 16 OCT 94 18 46 38 PEH LEWEL L ORDER l 6 1 1 61 066 B2 6 4 1 B2 anna 3 3 12 6 1 83 888 d 37 4 1 Gd mad ag 34 4 1 E15 maa ag 38 4 1 Be maa Jua KISS RPM 364i crsr 87s PCMOTOR STATUS HIDE TACHSET E FREL CAL FEH CHRHHEL ORDER The display is currently viewing 6 different orders as they changed in amplitude dur
30. ok N Ley 5 93 8 aa A x 2 HHHH dotted crar ROOMS lthresh hthresh A Preu H Hext DATA SOLID DOTTED BOTH Notice the RT60 value of 0 195 seconds at the 1 6 kHz band All of the other frequency s RT60 s are still set to 0 20 FEB 15 33 39 R RT amp B Auto RE Buta BU note RTE Hote SPL EFHGED 13 LINEAR FEPEAT 4 8588 bT IME Dual LIHEHE 24Hz 16kHz RESET 2H FEB 292 15 17 55 12 zm z25 H 1 66kHz 5 3 RTEA CATA r ET amp B 4 195 AWG Al G EN B B ISIS FEM AE s z z a A dotted crar POOMS lthresh hthresh Auto TH SUL LD DOTTED edit 13 Let s continue the manual process of completing the RT60 register Press EXIT to return to the decay curve display Then press DATA M 7H SE 15 34 37 RT6 REPLACE AVERAGE Auto RE Auto AL note Hate SFL ELE HS REPEAT B as ua LINEAR _26Hz 16k Hz A ZA FEB 98 15 17 55 nar 76 25 a hdo 5 SOLID DOTTED BOTH lthresh hthresh A Preu H Hext 9 19 2900B TRAINING MANUAL 14 Press the right arrow hardkey or increment to the next 1 3 y octave band 2 kHz gt ZH ear 15 58 53 RT66 REPLACE AVERAGE Auto RE Auto AL note Hate SPL WERAGED M davies O de ee a E LIHEHFE FEFEAT HL DG Dual LIHMEHR 26Hz 16kHz FESET 26 FEB 332 15 17 55 DATA 33 Z HHkHz 5 3 Channel 1 of 2 usTIME d 31 Td 1 1568 L A A A RS MES NUR CEST E ETE5E S H 218 ct 1 168 a ES n a Al a O O O O O E O O E Ley ar PC B ae 2 BDG new data DHTH SOLI
31. r E Aas robe K RR RRR NR R RIRE RR RRR RRR My RR ER a E RRR E e KE a aS DIFF Fh 52 5 n 7 45 L TACH 8 8 SPEED B a Color E R T r A R dotted creer McSTUP McWwAIT McREPT McSTHET McStop I Will cause the macro processor to pause during its execution un til the analyzer is in the STOP state at which time the execution will continue McWait J Used to provide a wait state during the execution of a macro McRept K Used to generate a repeat of the macro When this is used the macro will continue to be repeated until the analyzer is stopped manually by pressing the SPACE hardkey McStart L Sets the analyzer up with a time and date for the macro to start Executing Macros To execute a defined Macro the analyzer must be in the menu where the Macro was initially defined i e Main Menu System Menu The error message Macro Menu Mismatch will appear if the analyzer is not in the menu where the menu was initially defined 1 Press the MACRO hardkey to enter the Macro field SPACE MACRO 9 3 2900B TRAINING MANUAL The message MACRO Select 0 9 or Create STO Store will appear on the upper right side of the display 1e FEE 23 03 44 CREATE EIS RS TRIG 54 A NEN fae Bin E AS NR A tS ees Dro a A A IA a AAA REM TACH 8 8 SPEED B a iB A O s S dotted crar DUUE UZ 7 2 Press a letter I P where the Macro was stored For this example press the letter
32. units to be in g s understanding that we could easily make it meters per second squared feet per second squared etc 1 Press UNITS F to enter the units field pe ieu 231391439 HChanl s SLM A STANDED CROSS CO FILTER CLASS SPL EB BEBA mR EXPONENTIAL 178 Ineut 1 LINEAR ZEHz z kHz RESET z JAH 93 23 38 41 IHH FILTER 16 46 8 Hz Les a 1 E SR r D DIFF Ph 52 28 n2 2 42 REM o TACH Ha SPEED Bg d z5 H Hz Baa Hz 29 BLC HZ OFF INITIAL 1 0 SIG GEH INPUT clock COLOR MLS FILES FESETS The softkey selections at the bottom of the measurement dis play relate to the unit name that we would like the measure ment amplitudes to be displayed The softkeys K thru P are undefined fields You can assign any unit label that you like to each of the six keys Let s assign the unit label G to softkey K To do this first push name B 18 B amaad ae d sar ed ith Sale XE O ip Cag ep See cn s Real ee RN EXPONENTIAL 18 InrFut 1 LIMEHR 1Hz 1BkHz RESET 18 MAR 94 11 06 64 TE SAA Su hah ager e VE eee wht A A AE es ae whe ae oc AA FREQ DD ARRAHZ HSHH Channel 1 of HORM 15 3 12 Ja D TL cas Sint A TUTTI LOC TACH B 8 SPEED 4 4 Bm zD UM 1 2506 0060 Z A dotted crar UIEi dE el SPL Under under undet undet under Under 2 7 2900B TRAINING MANUAL 3 You are then prompted to select one of the six undef name keys Press undef K K 13 MAR 11 61 56 f 114 Push units to name SPL B m
33. uzEPM KEEP Hote 117 8h8 EXSPONEHMT IAL 1 64 ame 1 LIHEBHFE iHz lBkHz STOP 15 OCT 94 22 21 38 FEG AB BARBA H4AA Channel 1 of 1 NORMAL 54 7 a 1 5 TACH 36866 4 SPEED 48 8 brec all data H Freu A Mest 2900B TRAINING MANUAL Viewing the byTACH Autostored Data 1 To view the individual spectra that were autostored during CLEAR the run up press RECALL RECALL 15 OCT 22953937 W Fall E AWE B MH vsRFHM KEEP BE ll Es Tach 1 G B 6268 EXPONENT L HL 1 64 Ineut 1 LIHEHEF iHz 1BkHz STOP 15 OCT 94 22 21 38 i ma BRBBHz H4AA Channel 1 of 1 HORMAL d 78 3 76 7 TACH 366 2 SPEED 4 4 brec all data H Freu H Hext Press the right arrow hardkey to increment through each of the captured spectra 1 Another interesting way to view the autostored data is to uti Q lize the waterfall display capability of the 2900 Press A W FALL A to enter the Waterfall display window KEEP Hote 4 5668 ERPUHEHT TAL 1 64 Ineut 1 LIHEBR 1Hz 1BkHz TOP 15 OCT 94 22 21 38 s BB D962HzZ H4BH sc anne 1 of_1 JAL T TACH 666 3 SPEED 4 4 brec all data H Freu H Hext 2 First you need to establish which spectra to show in the dis play You do this by establishing a start spectra typically the E first or 1 an end spectra typically the last or in this case number 113 and a delta You ll set a delta of 3 This means that it will plot every 3rd spectra in the waterfall map Press ST
34. 1 kHz RESET Bv JAN 98 20 49 53 ro e ge Sat o e A e FEEL Hi 12556Hz ESHH Huto oe Un b 1 Ba ase Freauercy BE mai 1647 td zB Che TACH Ha SPEEDS B Hi 0000 Z o0mM T 2300 0606 Z A tri8 delas INITIAL ALTERHN BwWwHORM PEE SLOFE LEVEL DELAY 2 DELAY OFF 36 Press EXIT to return to the MAIN menu 37 The 2900B is now set up to make transfer function measure ments Press R S to arm the trigger 21 04 21 H SPFECT C SPECT amp s FEF COHER TIME DISPLAY note DETECTE Dual LINEAR lHz i18kHz RUM BY JOH 98 21 83 55 P a uve RU RR aaa A io XT aims oa LISTES ANO da al EN NL UR CO RR UNI ORIG Id QE NIS I ES o eae FEEL AZ 1258Hz ESHH Huta 5Srectr um D 1 11 3 E ae Bo dite tee Ee ee ele N ys Ae a a ees YD ar A he rai E es ae NAAA oe at as ae 02 Base Fresuenc a DG 164f td zH Ch2 Bad RE TACH H H SPEED B d 96 0000 Z O0mM T 2500 05606 A Lr delay INITIAL HLTEEH ElJHCOEP Fa gt R T TEIG SETUF FILES Bi Tris The 2900B is now waiting for the first average If you impact the structure and do not have a resulting measurement the input ranges may need to be adjusted Also the trigger level and delay may need to be fine tuned Providing that you are successful and have a good measure ment on the screen press SPACE to save the spectra and impact the structure again ui 21 56 29 H SPFECT C SFECT FER COHER TIME DISPLAY note DETECTE ag WOW RR NN X O4 X 5
35. 10 Press R S to acquire the second Autostore measurement For this exercise take 5 additional Autostore records at different microphone positions 11 After the 6th measurement is done press RECALL 28 FEB 15 09 49 W Fall B AVE B MAX B SUM usTIME KEEP Hate SPL ana LINEAR REPEAT 6 0500 Dual LIHEHR 28Hz i amp BkHz STOP 20 FEB 98 15 86 87 FILTER 26 468 Hz 53 e 1 S a ue r DIFF Ph 94 8 Sn 32 16 TACH BH SPEED B a re bT IME REM E z EH Hz S recall data ROOMS DELETE H Freu A Next EXIT 2900B TRAINING MANUAL 12 To average the 6 Autostored measurements together press B AVG B Block Average ZH FEB 15 89 49 l Fall E AWE E MA B SUM wsTIME KEEP gm 15109149 Fall CED en BSu vetm Hote SPL 1 8868 TH fc 4n Si wae ate ae Se Sandan Sab Gas ae ee EIS ae a PCM C ELE LINEAR EEFEHT A z ASA bT IME Dual LIHEBRE 26Hz 16kHz STOP 26 FEB 98 15 86 87 zB 5 nn o A FILTER 26 4AA Hz a4 Channel 1 af 2 HORMAL d E B 74 0 AB TT IIR BIFF Fhz 90 4 5n 32 15 T TACH 4 8 SPEED B d recall data z eod Hz ROOMS DELETE R Preu H Hext 13 At the top right side of the display answer the prompt for the Autostore records that you wish to have averaged together Since you want to average all 6 records type in 001 006 26 FEB 15 259 53 38 AVERAGE a baii a A EI LIHEAR FEPEAT A ASA bTIME Dual LIHEHE 26Hz 16kHz RESET 26 FEB 38 15 17 42 2S0l A FILTER E32 1 66kHz 542
36. 14 35 46 FILTER 4 1 228 Hz Lea Channel 1 af 2 HORMAL E Ora d PHONS 64 3 TACH 8 8 SPEED A dotted crear IMITIAL Averaging type FFT Filters LIN S A Linear Single seconds LIN R B Linear Repeat seconds EXP C Exponential seconds EXP N D Exponential averaging based on number of spectra Count S E Spectral Single spectra Count R F Spectral Repeat spectra EXP ESFU HM COUNT COUNT E Al TIME Hate TEST 1 F 2 zd EXPONENT L HL 1 8 Dual LIHEHR 2AHz 26k Hz STOP 63 OCT 94 15 17 14 FREQ HEHz H4AA Channel 1 of HORMAL d 45 1 69 TACH 6 8 SPEED 4 4 dotted crsr 3 Press AV TIME I to select an averaging time B3 SSL 15 16 32 LIH S LIH R EXP ETEF BIL LIN HU TIME Hate TEST 1 1 1456 EXPONENT L HL 1 8 Dual LIHEHR 2AHz 26k Hz STOP 63 OCT 94 14 35 88 FILTER 1 oH Hz L 3 Channel 1 of 2 HORMAL d B BS PHONS 64 3 TACH H a SPEED B amp dotted crsr If you selected a Linear type of averaging Lin S or Lin R you will be prompted to enter an averaging time in seconds DETECTOR TIME Epona BEBE M A A A A A gt im E EE LINEAR SINGLE B z5Hd Dual LIHEHRE ZbHz z kHz STOP 63 OCT 94 15 28 53 FILTER 1 56 Hz L 3 Channel i of 2 HORMAL B 59 3 d PHONS 73 4 TACH B B SPEED B a dotted crar B3 OCT 15 21 25 360 INITIAL 2900B TRAINING MANUAL If you selected an Exponential of averaging a display with 16 different values of av
37. 14 54 S cubes dd d x EL PLC E E 6 e 6 28 Hz Leo Press one of the following keys to select the desired detector ol 14 54 35 MORMAL Lea MIH HAs SEL DISPLAY note DETECTE i 24 39006 an EXPOHEHTIAL a Theut 1 LINEAR 2AHz 2AkHz i OF 11 OCT 94 14 54 69 rh FILTER 8 6 34 Hz Les Channel 1 of 1 HORMAL 3r a BHz 26k Hz Loc SLOW E m z aH Min 57 5 Max Er EN FEO BH 4 dotted crar lle iaht SETUP FILES AUTOSTR SLOM FAST IMPULSE LEG SLOW I FAST J IMPULSE K Leq L 2900B TRAINING MANUAL Averaging time of the Slow detector is one second 11 OCT 15 00 43 RT6 REPLACE AVERAGE Auto RE Auto A note i Hate TEST 1 3 i B 1666 bT IME Input 1 LINEAR z Hz kHz A terete ree ince ume T EXPOHEHT IAL 1 8 STOP 16 OCT 94 111241439 SLO r Ld 54 8 Td z Sa K FAS cay 0s a Calg des De i A K 105 O RT A ASA AS Wald Mate Saye Cip RR NAR 9 ET amp B3 Ha 26 ctr 1 4688 i THRESHOLES 64 8 55 6 LOC i hes ossi arto a cesa B 1066 Freya INITIAL S 10 9999 drew lthresh hthresh A Preu H eL FFEG SOLID DOTTED BOTH Average time of the Fast detector is 1 8 second puper 15501 02 ET amp H FEPLACE HUEFRHGE Huto FE Auto AL note e Hote TEST 1 B 10600 a EXPONENTIAL 1 8 bTIME Ineut 1 LIHEHE ZBHz 2b6kHz OF 16 OCT 94 17 24 43 r FILTER FAST Channel 1 af 1 usTIME Ld 55 2 Td i gH EIEH 51 66 ctr 1 4868 THRESHOLDS 468 68 25 6 LOC JA 1 A 10506 14 Badr new f
38. 16 Next press DETECTOR H to set up the measurement aver aging method Er JAH 61 33 55 H SPECT C SPECT FER COMER TIME CISPLAY nate DETECTE SFL B BeBe 188 g RR Cay get Ro ah EY Gus ca E O RNA NAAA ANN p EL 1 E al LINEAR 1Hz iBkHz RESET Br JAH 93 B1 52 126 Se RRR RR RRR UNS DNO RN N R RRR N Rie ab UC e GRO RE R RR N RRR A 8 oe RR N ERE QG ARRAHz ESHH Auto SEectrum D z i 11 17 7 eh Be edt O CD URL cate day E Jey ar AST GINA CRUCE cap OR 182182 ML E RR O REOR xo UNE NECARE Rc REA e CR cas C Baze E ra 46 HHHH REM t TACH p a SPEED a tl ga BOB ZODM T I246 S5758 Z A arange 18 INITIAL ALTERH EWHORM Park T TRIG SETUP FILES AUTOSTR O 2 I X OW SCREEN SYSTEM 2900B TRAINING MANUAL 17 Select COUNT M G averaging SFL B Baa L C EXPONENTIAL 1 3 LIHEHE 1Hz 16kHz RESET BY JAH 98 Bli 32 265 Bg our dee eo ai deta cdo uaa dam her arde NEC UN MR ER sn dey IC ta RD dap E B Ri RN yaa Hb EN Bo MEE UE aul RB nde Funda sean stanley rg FREQ He HRORRHS ESHH an pa T D 2 eg dog ouo oes e ERAS NC A E AA RIO AA A ee Se AAA Base Fresuencyu AA 9069 REM TACH 9 09 SPEED Ae QG m ZUOUNS T Iz46 8758 E A dotted crar IHITIHL COUNT M count manual accept averaging is the averaging method that should be used when one is measuring transfer functions using an impact hammer The COUNT M method permits the user to examine the data before the spectrum is accepted and averaged in with other
39. 2 14 Press one of the following keys to select the mode of opera tion UNE EU ss OH OFF ON RUM OFF RUH BURST SPL B ABBA 11H a Go a TEXTE A The ae Tem apt oe IA D E EXF HEHT T DL 1 78 Dual LIHEHR i1Hz 2BkHz i RESET 66 OCT 94 15 28 17 an Hsu ucc FILTER 24 z756 Hz Leo Channel 1 of 2 HORMAL d i A 66 7 PHOMS 82 5 T TACH 6 6 SPEED a wok Hz Ski D Hz A HE Hz noise DG 9 INITIAL FIHE WHITE DELAY LEWEL 2900B TRAINING MANUAL ON A Turns the noise source on OFF B Turns the noise source off ON RUN C Will activate the noise generator when the analyzer is in the RUN mode OFF RUN D Will de activate the noise generator when the analyzer is in the RUN mode BURST E Selects the burst mode The repetition of the burst key is set by pressing the Delay O key and using the horizontal keys to ad just the rate in seconds DG OCT 15134136 OH OFF OM RUM OFF RUM BUR BET 15 34 36 ON OFF et Oe d SPL B HGGG 1 18 O hh hh oh oh on mom omm om omm om omo nons hog osos non EXPONENT I AL 1 8 i Dual LINEAR 1Hz 2BkHz i RESET 86 OCT 94 15129117 aj ao sae pita Me Sed ge ey Fei Sate Soca Se eset QURE Be tate EC ee rx MI DL E FILTER 24 z754 Hz Leo i Channel 1 of 2 HORMAL A 64 7 Ta DEM ECT UI Sr E RC EP a eq gnum us PHOWS az 5 LOC TACH H H SPEED ALA wok A BRAS ol EHET E IMITIAL FIHE WHITE DELAY LEWEL DELAY O The Delay function permits you to set a delay for when the noise
40. 22 26365 FLAN A Ea od 15514 E RECORDS 7 delete rename delete Press the T E or 4 M key to scroll through the stored records until the desired record to recall is located AS OCT 16 86 24 create T nate EEEF Hemor Used ZEE Zd Disk Used Memoria Free 2 2472 Disk Free MEMORY DATE TIME SIZE IHTTIAL LOC 7 delete rename 1 23 2900B TRAINING MANUAL 5 Press the KEEP H key x H3 OCT 16 06 24 create T T nate kee Hemor Used zZ6624 Disk Used H Hemor Free a 2 Disk Free C Fo RECORDS 7 delete rename delete The message KEEP record and exit will appear on the right side of the display HS OCT 16 07 29 ES HO Memoria Used El Dee Used Hemor Free SEGRE Disk Free KEEP record and exit MAME CATE AL reread IHITI FLHHT 1070379 LOC 6 Press either the YES A or NO C key to answer the mes sage Pressing YES will recall the stored data record and ana lyzer configuration to the display leaving the FILES menu Pressing NO will return you to the FILES menu 7 Ifyou answered NO to the above step and no longer desire EXIT to manipulate the files press the EXIT key to return from the FILES menu Transferring stored files to a floppy disk 1 Attach the optional disk drive to the analyzer 2 Press the FILES O key found in either the Main Menu or the System Menu a et 15 50 31 NORMAL Lex NIH MAH SEL DISPLAY note DETECTA SPL 14 5568 TH A A A RRA ON Gat aa
41. 28 U 28B U AUTO RA TEST SPL 56 7575 3H K qc E ce ues vat ac Tua A DeL Pad SE UT A ET Ga ao ade URS anc te eh cat DERIT RC di V da a L tay ole ca EXPOHENTIAL 1 B8 Input 1 C lEIGHT STOP 28 FER 98 10 26 34 Eo R RR Lue Ise rcu MO et Geant ie HE FILTER 14 25 B Hz Le A dE Channel 1 S 1 OPDAL HERPES ne ae PLA DIFF Ph WET Sr R REM TACH 8 8 SPEED 4 4 H Hz mi H dotted crar IMITIAL A WGT i 20k 2020k 121k 28 18k SAME RANGE 10 Press the 1 20k K key This is what effect the 1 20kHz filter has on a spectrum ico 13 51 52 AUTO RA Ineuts TEST 7 JRE SPL 16 ERF HMEHT IAL 1 5 Dual LIMEBRE 1Hz z kHz STOP zd FEB 98 13 51 42 FILTER 12 16 8 Hz 5 3 Channel 1 pe HORMAL d x wa DIFF Fh 124 Sn 355 68 TACH B B SPEED B a DC outrut S jEk 29 10 SAME eFEHHGE 2900B TRAINING MANUAL 11 Press the 20 20k L key This is what effect the 20 20kHz fil ter has on a spectrum E 20 56 10 43 62 pu z8 U zm U AUTO RH inruts TEST SPL 17 9388 190 E AA O TOA E da A AE ue E Gus Smee T E dao O Gee ie EXPOHENTIAL 1 Dual LIHEBRE zBHz z kHz STOP 26 FEB 98 14142137 cr x FILTER 14 25 D Hz Les Channel 1 of 2 HORMAL d B 99 AC awl te ise cel ee Jas ena Oe A eek Gale a A She Se et A CIFF Fh 111 8 5n 145 rr FEM TACH 6 64 SPEED B d dotted crar z 1 16k zB 1 8k SAME aRAHGE 12 Press the 1 10kHz M key This is what effect the 1 10kHz fil ter has on a spe
42. 3 LOC TACH 8 8 SPEED mB 8 KS L E s z s z datted crar IMITIAL byTACH TACHSET F TRIG FILES 3 Press the delta C key to set the desired time interval between successive spectrum storages xil Bridger i OFF b TIME endstor nate I SPL B aaa 2B cc A O EE EXPOHWEWT IAL 18 bTIME Dual LIHEAR 2BHz ZB kHz RESET 64 OCT 94 Ws 455 12 B owes ec ad E FILTER 4 1 NE Hz Le 3 i Channel 1 af z HORMAL d A 4 7 28 n E dt tl Gap Uwe ale Goosen a MG wa Que cies tay A ae we se Ss PHONS Sd 3 LOC TACH 8 8 SPEED a 30 E tdotted crar z E z IMITIAL bsTACH TACHSET F TRIG FILES 1 27 2900B TRAINING MANUAL The message DELTA TIME XXXXXX XXXX along with a flashing cursor will appear on the upper right side of the dis play The DELTA TIME indicates how often a spectra will be stored during a measurement Ad OCT ar 49 09 116 h B LEE TELE i SPL i K E Aum ah E R a EN se a ee a RO v a A ah ee dE EXPONENTIAL 18 Dual LIHEHRE 2AHz 26k Hz RESET 44 OCT 94 m7 48 12 au E ETT FILTER H 1 5 Hz Leos Channel 1 of 2 HORMAL l A 34 7 O Po Sede A QT FHOHMS Sd l L TACH BH SPEED B amp dotted crsr 4 Use the left and right arrows keys to navigate through the EXIT time displayed and enter the desired time interval by using the numeric keys on the analyzer and press the EXIT key 5 Press the endstor D key to set the desired run time period T of the measurement D Bd OCT
43. 63 8 Sn 3 62 TACH 8 8 SPEED 4 4 ai MBB iRiniiriirrrmrr z L dotted crar under under under Under s Z g IMITIAL dE el SPL MSEC undet The analyzer has now been calibrated to a reference level and the reference level assigned to a Unit name You may assign up to 6 different Unit names with 6 associated calibra tion reference levels These names and reference levels may be stored as a file to amp the memory of the analyzer by pressing the STORE hardkey STORE for future recall Calibration based on a Transducer Sensitivity Value This topic will be covered in detail in the Vibration Analysis sec tion of this manual Selection of Filter Type Octave Fractional Octave and FFT To select a filter type press the Filter G key from the System Menu lo 16 68 17 Chanls SLM A STANDRD CROSS INTENSY UNITS FILTER CLASS E SPL 6 0008 aj r A A O cus INES az NEL R R y RR cee R IER E RR e a R city Pains ae e TE cia Sn EXPOMENTIAL 18 Dual LIHEHRE 2bHz Z6k Hz RESET 19 FEB 38 16 83 46 TH r ee ica T car O E E A A OE A E N N FILTER 14 75 8 Hz Leo Channel 1 of 2 HORMAL d 23 H 34 9 54 r EE OO Cun R RET ET EIA EST TRR O E OS R Cao EAE EE a CIFF Fh az 5 Sn 7 45 REM o TACH 9 9 SPEED B B zo Hz Bou Hz zB BEHz dotted crar IHITIHL I SIG GEN INPUT clack COLOR MLS FILES RESETS For Octave and Fractional Octave analysis perform the fol lowing 1 Press one of the following keys 2 5 2900B TRAINING MANUAL
44. 94 28 11 27 44 A NET I FREQ Ae BARAH H4HH Channel 1 of 1 HORMAL d 95 2 z 71 0 ED PETE TEE wa l l TACH H a SPEED B 96 0000 Z o0m 1 Saa Ba dotted crsr IHITIHL 13 8 EXIT 2900B TRAINING MANUAL 6 As mentioned at the beginning of this chapter you will be acquiring spectra from an accelerometer attached to a plate on a de motor at 20 RPM increments as it sweeps up in speed from 500 RPM to 3000 RPM The range of 500 to 3000 RPM is our measurement span for the autostore This range is entered in the t span field Press t span B to get into the tachometer span entry field 15 OCT 21 49 41 t scale t t e t inrut X cal SLOPE X AUG oT 21549541 L scale t sran t amin t amax t inrut X ca Tach inrPut jack E B midi 7E Sp mele A ei an ee RO a AR UE LORD RS m a RA R E ET R E Ge Gee AR EXPOWEWT IAL 1 64 bTACH Ineut 1 LIHEHEF 1Hz 1i kHz RESET 15 OCT 94 28 11 27 44 E ee ae a ON a RAR JR e s Jm Um SW OS a FREQ AA HnammmHz aan Channel 1 of 1 HORMAL d 95 2 E 71 9 m Em TACH 6 6 SPEED B Bn GREE 00m 1 DEBE 02006 dotted crar IHITIHL s scale s sran s amin s a4max EHDHE f RADAR m Type in the desired RPM range as LOW HIGH 00500 0 03000 0 15 d 21 30 22 PE e NR oa a oe A ee A we GA OM a 2500007000010 ee A Re EXPOHEWT IAL 1 Ed bTACH Ineut 1 LINERE iHz 1BkHz FESET 15 OCT 94 28 11 27 44 R iy vi RZ RT RC R R IE R RR RC R Ry IR IRR UE UR RM ee mp ey IND RR TR i
45. 98 95 365 51 2A r UE papas ia a a asi TH FILTER 14 25 8 Hz Les Channel 1 of 2 HORMAL 34 4 A 46 3 5i Cz I RR Gna time Yim acer cae layin A iy Mae aoe see Geer qc Cdp DIFF Pbs 65 9 Ens 6 85 RE E TACH a d SPEED 4 4 dotted crar DELAY SINE PINK WHITE PULSE INITIAL SINE I Swept sine generator PINK J Equal energy content per percentage bandwidth WHITE K Equal energy content per constant bandwidth PULSE L Pulse noise generator 1 Z J 2 3 SINE I 2 16 Select the SINE I key se OSS dd5 00 Fstart Fend R se k es Lse Les Z amp HTT gt ATT SPL B piana 146 EE ER dune er mds IO o A A K A ck EXPOHENTIAL 18 Dual LIHEHR 2BHz zBkHz RESET 26 FEB 98 H8 3856 51 ai EE asesores cdi ee R EE ETT A FILTER 14 zh Q Hz Leo Channel 1 of Z HORMAL d 34 4 H 3 15 Wi lc DM 2 Sop LE BIFF Fhz 65 9 Sn 6 85 l TACH 6 8 SPEED B a dotted crar z tone Auto L FILTER A Press Fstart A You will be prompted to set the lower frequency limit via numeric keypad where the sweep will begin zB FEB 49 61 45 Fstart Feng k se E es Lee Les amp HTT HTT 125 r id R 9 MT 9 9 AIT R RRR R NNN R RN N R N N SFL 4 Ela 140 r as ios cea Sah tae UNT Ged E OE A RNA O Cas CRDI EXPOHENTIAL 18 Dual LIHEHE ZBHHz ZzBkHz RESET 26 FEB 98 8 56 51 ai r fie sy e A Ou uL Bee AR de o ll A A VES Ge E A A A E Go RR FILTER 14 75 4 Hz Leo Channel 1 of Z HORMAL d 34 4 be 46 3 5h
46. A iet uu eC SN FILTER 14 25 Q Hz Leo Channel 1 of 2 NORMAL d 34 4 H 46 3 By r A RA NN e E aa te CIFF Fh 65 A Sn 6 85 RE l TACH 4 8 SPEED B El 25 5 Hz 6360 Hz ZH HE HZ L dotted crar INITIAL AIS TART alEHD SHEEP LIH 2 tone Huto L FILTER As mentioned above press T se C and T es D to enter the desired start to end and end to start sweep times F Press L se E and L es F to adjust the output level start to end and end to start oF FEB 03 01 08 Fstart Fend R se Fes Lse Les HATT gt ATT 1 SPL B BREE 146 R gp IX ee ae TREE TRE EXPOMENTIAL 18 Dual LIHEHRE 2 amp 8Hz zB kHz RESET 26 FEB 93 95 265 51 ai A LX c C E FILTER 14 75 8 Hz Leo Channel 1 of 2 NORMAL d 34 4 H 3 By ke o a a ee EET ce DIFF Ph 65 A Sn 6 85 REY l TACH BH SPEED B B 5 8 Hz Bae Hz 20 BEAZ L dotted crar IHITIHL as TART aEHD SHEEP LIH Z tone Huto L FILTER G Press START I or END J to assign the sweep to begin at the pre selected start frequency or end frequency me 92 63 01 08 Fstart Fend R se kE es Lse Les HTT gt ATT SPL B BREE 146 PIC A e A a a aa A E il EXF HEHT T DL 1 75 Dual LIHEHRE 2 amp 8Hz zB kHz RESET 26 FEB SS BH8 356 51 SH r i NN NR RR K RR RR RN RN A A a R K a A R 727 183 FILTER 14 75 8 Hz Leo ge nanne 1 pE pos GA L DIFF Ph 65 9 n2 6 85 l l TACH B B SPEED B a dotted crar z tone Auto L FILTER K o 03 01 08 Fstart Fend R se k es Lse Les HATT gt ATT SP
47. AB Xu T TI C pcc E BIFF Fhz Za 1 5n E 44 J l TACH H H SPEED B d dotted crar ROOMS 5 For the RT60 autostore measurement you should select a very short averaging time Type in 0 05 seconds as shown ZA FEB 13 31 23 38 GM ee DETECTOR TIME 262000 0510 TH sia o UA ET N R 0 N R RT RTT T R RT E N R RTA EE CENT LIHEHFE FEFEAT Dual LIMEHR 26Hz 16kHz RESET zH FEB 98 12 z o FILTER 14 25 8 Hz 3 Channel 1 of 2 HORMAL H d B 23 4 o DIFF Ph z 28 1 Sne d4 REM l E TACH Ha SPEED Bg d dotted crar ROOMS 6 Press EXIT to enter this value Notice that the established EXIT detector parameters appear on the right of the display 28 BEE 12 25 18 LIN S LIN R EXP BT EXP ET LIH RU TIME 75 E 1 RESET 20 FEB 9 12 29 56 SD r UT PPP lt FILTER 14 z5 IS Hz Er 3 Channel 1 of 2 HORMAL d z 23 0 AA DIFF Ph 28 1 Sh dd REM J l TACH 8 8 SPEED 4 4 dotted crear ROOMS 7 Press EXIT to return to the STANDRD analysis menu EXIT 9 8 2900B TRAINING MANUAL 8 To enter the Autostore menu choose AUTOSTR P zH B 13 33 52 HORMAL Lea MIH HAs SEL DISPLAY note DETECTFE SPL HERE TH RI ER c lp Rx c ee ee LIHEHE FEFEAT B Em Dual LIHEHRE 26Hz 14kHz RESET 26 FEB 98 131311271 SH BRE ete AE AE TE Seles A Re encanto ete nsu AA oP FILTER 14 75 8 Hz Sri Channel 1 of 2 HORMAL d B B 273 48 Ab LLL CLERI c c a ag BIFF Fhz To 1 Sn E dd REM TACH 6 6 SPEED B B
48. ARR JB RPM S86 crsr l DCMOTOR The vsRPM graphics display is now viewing the first 6 orders harmonics as they changed in amplitude during the dc motor run up The orders that are currently displayed are shown on the right of the display Notice also that each of the 6 traces are labeled accordingly on the left side of the display 16 SS 15 12 25 SLOPE aleuel TAGBARS amp SPHH WIDE A HAIS nate WIDTH SOURCE IS TACH INPUT B 0200 NOU PURA ERFU HEHTIBL 1 64 Input 1 LINEAR 1Hz 16kHz RESET 16 OCT 94 15 42 36 FEH LEVEL C RDEF l 36 6 1 41 mam 2 B2 56 6 1 BZ 202 A A 0 us 3 Az SA 4 1 B3 Bo 4 Bd 32 5 1 B4 2029 4 Bo 32 5 1 95 ma Ke RN AENA Be 27 d 1 Be Bo 306 SHBG RPM 566 crsr Bl DCMOTOR STATUS HIDE TACHSET B FREB REDRAW PEM CHANNEL ORDER Push the right arrow hardkey to move the cursor along the RPM axis The amplitudes of the orders at a particular RPM are shown at the right As you did with the frequency display you can eas ily modify the order number that you wish to display in the same way To change the display to orders Press B ORDER L 16 SET 19 45 87 SLOFE alevel TAGEARS s SFHH LIDEO pH IS note WIDTH SOURCE IS TACH IHPUT B A288 ERPUHEHT IAL 1 64 1Hz 18kHz Real time vsRPM Graphics There is a method of acquiring vsRPM data without using the Autostore feature This technique allows you to view frequency and order curves live as the data is being acquired You will 13 20
49. After you have established the values of these parameters press EXIT to enter the changes 12 21 2900B TRAINING MANUAL Naming a job part and area EXIT EXIT 12 22 For a sound power determination we need to give the test a job name and create names for the components part and subcom ponents area 1 Press job I to enter the name creation field for the job name 12 de 21 11 37 POWER INTHSTY QUALITY SPL F WELOC DISPLAY note DETECTR B BEE I 1 8 D LINEAR 26Hz 16kHz i RESET 12 JAH 98 21 18 44 iB FILTER 274 z568 Hz Les AN vr INTENSITY i de 130mm ET ug duca ed pc ic pru der a ia IEEE Ped ws de POl 19 41dBE 61 09002 REM i PART GA Aresa es eens We gh ete L AREA 25 8 Hz Sud Hz 18 6kHz E A ranue a HITEST Fart area PrertrsP meter SETUP FILES AUTOSTR Press the various alpha soft keys to build the job name that you desire Then choose EXIT to enter the job name 12 JAN 23 16 56 A E c D oH POTE A E cao cde a cis val s cr de ae ude nein EC RS HR a TRO URS TR RT 25 8 Hz 588 Hz 18 8kHz E A ranae Sa AITEST I J E L M H P Press part J to enter the name creation field for the part name 12 aon 23 17 13 POWER INTHSTY QUALITY SPL F UELOC DISPLAY note DETECTR dEF m E mia SH Hb ie ee att aac T CK GA dae eS R a Dec hue Nn CE RC Gare WP TRT i CA T cake om wo Sa ac o cum Se eas a de At ae EXF HEHT T DL Dual 18 FILTER 424 256 Hz Les DM gt isi auis CR A 32 54
50. B a recall data DELETE A Preu HB Hext 2900B TRAINING MANUAL The message AVERAGE 0001 0002 will appear on the upper right side of the display Ad OCT 23 37 58 116 Rage Au Hur AVERAGE B B1 0892 Z Efi IS E et ao Ga seo Sl a RR L ae MTM EXPONENTIAL 18 Dual LIHEHR 2AHz 2Bk Hz STOP ad OCT 94 995 DG 5 258 SL R RN n N P RR T FILTER 77 KAR Hz Les Channel 1 af 2 HORMAL d i A 39 6 PHOHS 3 3 l TACH BH SPEED B brec all data INITIAL 3 Press the numeric keys and horizontal arrow keys to enter the range of record numbers of the autostored records to be averaged together 4 Press the EXIT hardkey EXIT Upon pressing EXIT a single averaged autostored record will be created and stored into the next available record number The word AVERAGED will also appear on the right side of the display indicating that this autostored record is an aver aged record 5 Press the B SUM D key to select the desired records to be T summed together SES 19 54 86 W Fall B HUE B MAK B SUM J zTIME KEEP Hate F 5 AHHA a 1 8 bTIME Dual LINEAR zHHz z kHz STOP 24 FEB 98 18 44 85 PO FILTER 27 SGA Hz Les aoe eae 1 uS LORI r Sa DIFF Ph 74 1 Sn 10 63 REM TACH 8 8 SPEED 6 4 S z z E hrec all data DUUE UZ DELETE H Freu H Hext The message RMS SUM 0001 0002 will appear on the upper right side of the display 24 FEB 26 42 15 Last H 110 SPL B 1666
51. B Soc on ee meee coil 7 9 Avers lg e cio 7 13 OT OEI dde 7 15 Integration and Double Integration sss sese eee 7 17 Sound Level Meter Operating Modle 8 1 Sound Level Meter with Frequency Analysis 8 1 Changing the SLM Analog filters occcccccccnonnocncnnnnnnnnnnnnonos 8 4 Wide Dynamic Range Sound Level Meter No Frequency W O Semen aren 8 5 Room ACOUSTICS iia 9 1 Sound Decay Measurements R ToS sss 9 2 Setting up the RTA for RT60 measurements sss sese eee eee 9 2 Creating a Measurement lG sese 9 3 Setting up the Microphones and Noise Source 9 5 Establishing the Averaging Parameters for the RT60 Measurement ars si 9 7 Setting the Signal Generator Delay sese eee 9 11 Making the RT60 Measurement sees 9 12 Viewing the RT60 Reverberation Time Values 9 16 Sound Transmission Loss Measurements sees eee eee eee 9 2 25 Making Airborne Sound Transmission Loss Measurements 9 27 ERO STT sound ISOIGLOFE sitios ee tasti esa seimbenicd odo ias 9 34 Nore RAMOS os 9 35 Norse Critertom NC IA I a a a 9 35 2900 TRAINING MANUAL Noise Rating Curves NR IB Dinar 9 36 Room Criterion ROTA te d 9 36 Chapter 10 Statistics and Ln Calculations 10 1 ImiLo IAN MOI E IONS CT 10 4 otorine the Ln Trace unidad 10 4 tormes the Statistics T3ble uiuere te p se
52. BB A qR SEL aay al wey Rs AA SNES LIHEAR SIWGLE zB BRB Dual LIMEHR 2BHz 26k Hz STOP z3 FEB 98 16 14 45 r 2 250505 A ai FILTER 14 25 4 Hz Leo Channel 1 of 2 HORMAL d 41 48 A 83 6 r C ra E E E E AS TEN UM II m DIFF h 18H 1 Sn 64 61 RENE TACH Ha SPEED B d H Hz Eod Hz z doatted crar ROOMS SIHE FIHK WHITE DELAY Once again it is common practice to make a number of mea surements at various locations in the source room and then average them together This yields a better statistical result by averaging out background noise etc Move the microphone to another location Press R S to begin the second measurement a 16 26 31 OM OFF OH FUM OFF RUM ATT ATT DIFF Ph 96 7 5n 31 26 TACH 6 8 SPEED B a dotted crar ELAY REM R Hz Bad Hz a E ROOMS SINE PIH WHITE PULSE Once the measurement is complete press STORE again to save the data to memory 9 27 2900B TRAINING MANUAL For this exercise make one more measurement in the source room at a different microphone location then store it you now have a total of 3 measurements in the source room Before you average them together let s perform the mea surements in the receiving room 5 Leave the speaker in the source room and move the micro RESET phone to a desired location in the receiving room Assuming R S the pink noise generator is still turned on press R S to begin a 1 3 band octave sound pressure measurement in the receiving ro
53. DIFF Ph 52 2 Sn 2 4z SEE TACH HH SPEED a el 5 8 Hz 6348 Hz ZA DL HZ dotted_cre sr IHITIHL I O SIG GEN INPUT clock COLOR MLS FILES RESETS Then select the desired resolution of the narrowband mea surement 100 line I 200 line J 400 line K or 800 line L by pressing one of these soft key options For this exercise choose 800 line L ar TEH B1i42 15r l1 loct loc L lona short reverse EB SBR L 1 38 HEAR 2BHz 26kHz JAH 98 B1 3233 28 25 8 Hz L 3 af 2 HORMAL A 34 9 52 8 Sns 2 43 doatted crar EASE Ed After selecting the resolution select the measurement base band frequency by pressing BASE Bd O ae Bli42 15rf lrloct 1l Soct lona short reverse SPL B BREE at ALL LLL LLLI c EXPOHENTIAL 18 Dual LIHEHR 2BHz zBkHz RESET ar JAW 93 Bi 339 28 TH A ee Yee a ioe LL LU E FILTER 14 75 8 Hz Leo Channel 1 of 2 HORMAL d 23 6 H A SH A A Se Re ee A DIFF Fh S78 n 7 45 REM a TACH 4 4 SPEED B B 23 0 Hz Bon Hz 20 kHz FUN ed crar IHITIHL 1991 1ne zBBHlire 488line 2001 1ne FFTZOON WIMDOW_BASE By 11 17 2900B TRAINING MANUAL 5 Your choices for baseband or upper frequency limit are 20 T kHz A 10 kHz B 5 kHz C and 2 5 kHz D Since most D of the interesting structural resonances occur at the lower frequencies and the impact technique is limited to lower fre quency excitation choose 2 5kHz D ee aligi ar z kHz lBkHz Sk Hz z kHz SPL B AGHA A EXPONENTIAL 1 8 LINE
54. DS 65 2 oh D AO ER EET a X LI IL CL E EE FILTER 14 25 8 Hz Les Channel 1 of 2 HORMAL d 34 4 A 46 3 5i E A R BEES E NN NR T BIFF Pbs 65 9 Ens 6 85 DES l TACH 4 8 SPEED B B z dotted crar z5 H8 Boel Hz IHITIHL aS TART alEHD SHEEP z tone Auto L FILTER Log Mode When the Log mode is selected the sweep rate decade second is controlled by pressing R se C and R es D 2H FEB 035 025 Zd Fztart Feng T se T ez Lee Les lt ATT HATT 125 r KR T O E O T dat nde ie Sal Sine See OFF Lime 44 1 SPL EB ma 146 r RR N ines Jar a e A A O a A ee T RT TIAE EXF HEHT HL 1 78 Dual LIHEHE ZzEHz zEkHz RESET 26 FEB 98 H3 36 51 ai r A AN RARA A O FILTER 14 75 8 Hz Lera Channel 1 of 2 NORMAL d 34 4 By r K LRR Gs O RE al T T Gal 8 Sa RTR Sen uty E R R E RT gue RR AO a R R R Vat 06 RT RN DIFF Fhz 65 A Sn 6 85 REM ig TACH H H SPEED Bg d S H Hz 6360 Hz ZH QL HZ dotted crar IHITIHL aS TART alEHD SHEEP LOG COUNT zZ Lone Auto L FILTER 2 17 2900B TRAINING MANUAL Lin Mode When the Lin mode is selected the sweep rate is still controlled by pressing the softkeys C and D but in this mode the sweep rate is in time seconds instead of a rate Do 03 01 08 Fstart Fend R se R e Lse Les HATT gt ATT SPL B piana 146 E Il IM p c LLL T x lc l T EXSF HEHT T DL 1 79 Dual LINEAR 26Hz 26k Hz ua RESET 28 FEB 93 09 46 51 ad cuu zai N sls aw ele A COE fate i ca Sla slaty Deb d
55. E NN FREQ Aa ARRAS HSHH Channel 1 of 1 HORMAL s 46 3 E 34 9 39H EM im UE 14 1 e REM TACH 8 8 SPEED 4 4 116 MMC O S 192 AA oe 1 Ba AL solid crsr IHITIHL undef Under undet undet 17 At the Enter setup name prompt type in VIB1CH or EXIT whatever label you like Then press EXIT Enter setur name WIBICH LIHE HHA Ineut 1 LIHEHE 1Hz 1BkHz STOP H i JAN 93 99 d15 1 2 FREQ He BBBBHAz HSHH Channel 1 of 1 HORMAL s 46 3 E 34 9 TACH 8 8 SPEED B a solid crear H U P 18 Next we need to store the current active setup to the VIB1CH K setup key Press STORE E then VIB1CH K K gt BOOT note 1 ZD ARE IHGLE ZD GRRE LIHEHR iHz lB8kHz 3 JON 38 06 41 13 HA 99002 HERA 11 of 1 HORMAL E 34 8 8 SPEED B a solid crzr under under under Under 7 21 2900B TRAINING MANUAL The vibration setup is now stored to the VIB1CH K key This setup can be activated at any time by pressing this soft key from within the SETUP menu 1 22 CHAPTER Sound Level Meter Operating Mode A sound level meter is an instrument designed to measure and display the broadband sound pressure level of an acoustic sig nal Very stringent performance specifications for sound level meters have been established internationally The Models 2800B 2900B are designed to satisfy or exceed the requirements of the following standards e ANSI S1 4 1983 TYPE 1 e EC 651
56. ERE SIS El 56 e A A A A Re eine me di eT E eh can eae a N 94 E 15 Hz HSHH Channel 1 of 1 HORMAL z 115 E BY r 5 E E NR AN REM n TACH 4 8 SPEED A El Bi E S EH solid crar INITIAL I O SIG GEN IHFLT clock COLOF MLS FILES RESETS 3 The integration and differentiation functions are in the Q SLOPE window Press SLOPE A to enter this area A az TAN ee 17 name SAME R LUHITS Hoise F mU cal U cal level n B Bad Sct d oa d epoca iced eu eee LIHEAR SINGLE 24 AAAA Inrut 1 LINEAR _1Hz 1 kHz FESET 83 JAH 92 995 Zd5 se 36 A O A a O A O TEE a E FREQ He HHHH HSHH Channel 1 of 1 HORMAL z 115 H e 87 7 5 pore NTN a ae gs A A K N RR A RA N NN ae SE E NM RR ae ce Belle TACH Ha SPEED B d HE solid crear 3 EA IHITIHL dB vU SPL G under under under under Under Within this menu you have four choices differentiation double differentiation integration and double integration The differentiation functions d2 dt2 and d dt are used in the instance where one uses a displacement or velocity trans LG R 2900B TRAINING MANUAL ducer and they wish to display acceleration In this case the user should be cautious to analyze data only within the fre quency response constraints of the transducer Velocity and displacement transducers typically have limited frequency response characteristics For this experiment let s perform a single integration on our accelerometer The result will be a vel
57. Enter nuni TL eB X R T a a E a A aa TITAT EXPOHEHTIAL 18 Inrut 1 LINEAR 28Hz 26kHz RESET 15 OCT 94 19 36 26 4 S 6 Tay er RN n E YS UTI FREQ Ae HARAH H4HH Channel 1 af 1 HORMAL d 15 3 2 Loc l TACH H H SPEED B a 96 ami o0m 1 Saa Bm dotted crsr INITIAL 19 Press EXIT to enter this scale factor EXIT gt 20 Press EXIT again to return to the System menu EXIT 21 Typically with vibration measurements one is interested in low frequency information Let s modify our high and low K pass filters from the current 20Hz to 20 kHz selection Press INPUT K to enter the Input menu 15 EE 19 55 54 SLM STAND 1 STHHD 2 CROSS INTENSY UNITS FILTER CLASS TACH 8 8 SPEED x dotted c SETUP FILES FES 22 Choose 1 10k M to activate a high pass filter at 1 Hz and a i low pass filter at 10 KHz M 15 ae 19 59 26 Bu 29 U Zhe L AUTO RH TEST a B mid 29 e TM Rr eh o NE a r E LET UA a a h A en ee R as A RE A EXPOHEHTIAL 18 Inrut 1 LINEAR 2BHHz zbBkHz RESET 15 OCT 94 19 55 12 44 arde A O Rer tae RP AO A oa ene oe SS AS wale wes dea dd ra ae alge a a r A FREQ Ae HARAH H4HH S enone 1 of 1 NORMAL LOC TACH 8 8 SPEED B A dotted cr z 1 k SAHE eM EXIT 23 Press EXIT to return to the System menu 24 Next you need to modify the exponential detector integra tion time to a faster rate than the 1 8 seconds that it is cur EXIT rently set at Press EXIT to enter the STAND analy
58. FFT press EXIT and go back to Signal Generator Wideband white noise can be used with either digital fil ters or FFT analysis The LEVEL E lt ATTEN G and gt ATTEN H keys are used in the same manner as described above for the pink noise generator ia 195 195 2 3 OH OFF DH RUM OFF RUH amp HTT ATT SPL 427 4568 EXPONENTIAL 1 3 Ineut 1 LINEAR ZBHz 2b6kHz OF 6 FEB 98 18 89 55 FREQ 66 BBBBHAz HSRA Channel 1 of 1 HORMAL d 63 9 n ar TACH BH SPEED B a dotted crar SIHE FIHE WHITE DELAY When FFT analysis has been selected a pseudo white noise output is possible The Pseudo White Noise Menu shown below is accessed from the White Noise Menu by pressing the key PSEUDO A When FFT analysis is taking place the analysis repre sents a finite number of frequency bands based on the number of lines selected for the measurement 100 200 400 or 800 It is not really necessary therefore for the generator to produce a truly wideband signal In the pseudo white noise mode the signals are generated at the center frequency of each of the bands represented by the lines of the frequency analysis This permits the generator output power to be concentrated on the same frequencies which are being measured by the FFT analysis even when zoom analysis is being performed 2900B TRAINING MANUAL PULSE L The Pulse Generator Menu shown below is accessed from the Signal Generator by pressing PULSE L
59. H CEXITIJ done CURSOR J delete LEHMBSET1 2newline SPL 1 7458 ERF HMEHT TAL 1 8 Dual LIHEHE 28Hz 28k Hz STOP HS OCT 94 14 35 08 FILTER 1 26 Hz Les _Channel 1 of 2 HORMAL B ofa PHONS 64 3 LOC TACH BH SPEED B a INITIAL I J E L M H 0 T p Begin entering note TEST 1 in the text field If you make a mistake entering the text you can highlight the character by moving the cursor with the right or left arrow keys then press the CURSOR hardkey to delete the wrong character If a note has been previously entered and you desire to mod ify or delete it and start new press the SHIFT CLEAR hard keys and the entire text field will be erased ready for a new entry 2900B TRAINING MANUAL EXIT 4 Press the EXIT hardkey once the desired note has been Selection of Detectors as LIN S A LIN R B EXP C BT EXP D entered into the text field You will now see the new note on the right side of the display B3 ge 19 14 32 HORMBHL Lea MIH MA SEL DISPLAY note DETECTE Hate TEST 1 i 1 1456 TH ias Sb Sarat Sa E E E E NR RT area ab NEAR EXPOHENTIAL 16 Dual LIHMEBR 2BHz 26kHz TOP mi OCT 94 14 35 88 54 p N N a KTN E RA A E O E H aly E 6 ae ae be N 0 FILTER 1 MI Hz Les Channel 1 of 2 HORMAL i d 15 7 B 5Y 3 3B L HI FH HS 5d 3 LOC E TACH 9 9 SPEED B d chk Hz Hz dotted crar INITIAL FOOMS us EPR STAT Hx d oc F TEIG SETUP FILES AUTOSTR When a spectrum is stored
60. Hz JHE Hz 1B8 BkHz A dotted crar HITEST jab Fart area Fr ALz zp meter SETUP FILES AUTOSTA 14 If you are interested in determining the total sound power Y emanating from your test item press S gt JOB I 13 de B1 14 14 Power F2 P I F3 HPF F4 FHU nate i SIAP RRA 1 dB Pl B SH S PITE Gee E A A atqiie vd LIHEHFE SIHSLE 2H Q i Dual LINEAR zBHz 1B8BkHz f RES ET 13 JAW 98 915 1 2 15 FILTER 25 215 Hz L Ba Four iu i d 183 44 TAA Eid E 54 ls iste ee R aie Melee a pera ee ae Rp eater Pap Scoop ILE dot BG 34 64 Hz AZ B4dBrgl JOE TE REM i PART FRONT aj CELER NER E E NOCTES T GERIT LISTS LISSE AREA FOIHTI1 25 8 Hz 5a HB HkHz E A doatted crar HITEST POPHET S HEEH 5 EDIT DLixF4d z Dz F4d 2 FS FZ Notice that the job name appears at the top right corner of the display This field tells you which data will be used for the sound power summation calculation B3 AUG 15 42 87 Power F2 F I F3 HFF F4 FHU nate 168 A a ea ee ROO Gres PPP E ET EE PET PET JE lt B aaa ED DERIT TII E E HE LE zB ABBA H SIHG Lal LINEAR zBHHz 1HBEkHz RESET 63 AUG 94 16 46 95 ZD pS se me B B FILTER 14 25 8 Hz L73 F PONER 1 d 13 6mm d 19 34 TAG BABE Z e R 97 TT IIS TUTTI 3 54 Hz 31 r4dErhl JOB TEST LOC PART TOP 16 O RE OR AA RR RAN AREA POINT 25 8 Hz Su Hz H HkHz Z A ndotted crsr HITEST SJOB S PART 55HEEH S tEDIT CitF4 2 Cz Fd z F3 FZ 12 28 2900B TRAINING MANUAL 1
61. J mm A LU LD L bL pex G A cl m Cl a Z m a T a R E m D zx m 2 m m m D TY m TA zu ul KA N ked ma 4 m pex pos Gl Gl SPL ro VA AS A A PTT EXPOHENTIAL REM TACH H a SPEED B a is C QG HAHA ZUOUNS 1 16606 09000 Z A datted crar INITIAL T LIHME 306 BAB 1206 S48 4506 9688 19768 The message 3200RC is ENABLED will appear on the upper right side of the display This module permits the user to perform the following activities 1 Run the analyzer 2 Stop the analyzer 3 Stop the analyzer and store the data block 4 Examine the names of the seven user defined analyzer set ups 5 Reboot the analyzer to one of the user defined setups 6 Press the 3200RC A key again to deactivate the remote control and regain control of the serial port A Control of the DC output port There is a connector on the rear of the analyzer indicated on the back label which produces a DC voltage proportional to a user selected frequency or SLM parameter Full scale DC out is 4 5 volts decreasing 1 volt 20dB i e 4 volts over an 80 dB range 2900B TRAINING MANUAL 1 Press the DC out B key 19 98 ir 14 32 JARC 10 Port l KEY A 7 KEV E Beerer RS1 IHT SPL EB ma ro doit pat wake RR RR RR EXPOHENTIAL Ineut 1 LINEAR 2Bhz ZBkHz FESET 19 FEB 33 11 68 36 B owe deo es Uaec WOO D cmi CR Os UE CES ccc wc as cea A Oe coe c NCC Es QE OR OL OO ER dero el eO EDD OR FREQ A
62. L FILTER Autolevel Control Auto L O Eo 69 48 56 Fstart Fend R se k es Lse Les L1 aF SPL 116 7656 148 K RRR NR R RN N N RR R K RR NR RR N N N NR RR RR RR RR R N N NR RR R R R NR R R ir E ua 1 LIHEAR 2BHz zBkHz STOP zH FEB 98 89 45 16 120 rum E RESTITIT UOIUTIDTITPITIUTT FILTER 14 75 4 Hz Leo Channel 1 of 2 HORMAL d r58 2 H 119 8 168 X RRR X X Em ucl Ilcllc BIFF Ph 121 2 n Z OB B8Z TACH 6 8 SPEED B a E z Gred crear INITIAL als TART alEHD SHEEP LIH 1 tone huto L FILTER This feature is used with the dual channel Model 2900B to perform calibration of accelerometers and micro phones For accelerometer testing the output of the sine generator is used to drive a shaker upon which are mounted both a reference accelerometer and a test accel erometer The signal from the reference accelerometer is connected to the Channel 1 input and the signal from the accelerometer under test is connected to the Channel 2 input The instrument is set to the STAND 2 Mode with FFT filtering active and the Max level selected for display M Press Exit to return to the signal generator screen The Wideband Pink Noise Menu shown below is accessed from the Signal Generator Menu by pressing PINK J SPL 6 oo 120 L erorsrrrrrr ranar n nnee EXPONENTIAL 178 Dual LIHMEHR 2BHz 26k Hz STOP zH FEB 98 09 52 35 199 r 2 E FILTER 14 25 8 Hz L 3 H SHS HET 1 a oe r Quom A SER E M eO AE d A DIF
63. Mes 325 d 3 SLOFE name SAME EUNITS Hoise F mU cal U cal level 5 H 6 AGAH EG a TN A RT N WAS an WE a E S LIHEAR INGLE zB BRB Ineut 1 LIHEHE 1Hz 1BkHz FESET 83 JAH 92 995 32120 1 45 N A R T a AL E YN A day AD a R tel vl Guy AECI yak Vat Ses vus Tae ve MR da Mara Guy LR PO FREQ d ARHAHz HSHH Channel 1 of 1 HORMAL s 152 9 E 125 1 1zt ka R RN R RT LR R e 1 7 TRT E epee dan TTIMTI K aN 7 Gane N N E EO EDI TACH Ha SPEED a d da solid crear IHITIHL dB vU under under under Under 10 FT S has now replaced G in the unit field of the display az de 433141 SLOFE name SAME R LUHITS Hoise F mU cal U cal level E TH ER NE NE R 2 at ee cB Sue wake R R BT ee a a as N R ae AE ee N Gen en Hy ae Rae dee bb See R See ae 78 Ge SING 2H EE PEUL 1 LIHEHEF 1Hz 1 kHz FESET 63 JAH 2 SH EC A O A E Tee E A NA AS FREQ Q HHz HSHH Channel 1 of HORMAL a Y Ab NR O a a ee SEP lt TACH 9 9 SPEED a d de x solid crzr IHITIHL dB vU SPL G FT75 under under under Under Next the calibration value sensitivity needs to be changed When we calibrated originally we did so in g s Recall that we first calibrated the RTA by typing in the calibration value from the accelerometer calibration paperwork directly into the mv cal field In the example we discussed 10 mv g was the value entered In this case we need to convert this sensitivity value to mv per ft sec 10 mv g x 1g 32 2 ft s
64. NR N FREQ A ARRAHS HSAR Hutao SEgectrum d 15 3 Ee 12 6 ae A ARA AAA fag Mrs Base Fresuenmncaz AB HHHH REM E TACH amp 8 8 SPEEDS 4 4 aa EH dotted crar INITIAL Press EXIT to return to the filter menu When making FFT measurements windows often need to be applied to the data to prevent a phenomena called spectral leakage In the case of an impact modal test an impact win dow should be applied to channel one and an exponential window to channel two O 2 EXIT 2900B TRAINING MANUAL 9 Select WINDOW N Sr Bli42 15rf lrloct 1 43oct lona short reverse SPL B BREE I6 r IEEE EE RN ab Gea E RO ET E RT ate a A RRR A RN NNN a N EXPOHENTIAL 18 Dual LIHEHR 2HBHz zBkHz RESET Br JAW 93 Bi 39 28 rar O E Je ate die Gat adie ene A RRA NN R R R FILTER 14 25 Q Hz Lera ga 1 Ets PORTAL A DIFF Ph 52 8 Sn 2 4z REM TACH H B SPEED B B oso Hz Bae Hz ZH HE HZ dotted crar IHITIHL 199 1ne 296 1 1ne 468line 29601 1ne FFTZOO WIHDOW BASE Bd Selecting an exponential window EXP 2 F EXP 4 G EXP 6 H automatically assigns an exponential window to channel two and an impact window to channel one EXP 2 F applies an exponentially decaying curve to the time domain response acceleration so that the response decays to zero at approxi mately 50 of the measurement duration EXP 4 G insures that the measurement decays to zero at about 25 of the measure ment duration EXP 6 H insures that the me
65. P SP 2B 9209 aH II LIHEAR SIHEGLE zH Dual LINEAR 2BHz zBkHz RESET 23 FEE 932 10 eh r VV FILTER 14 zh Q Hz L7 E ME Channel 1 S Z HORMAL L ur BIS A TT DIFF Ph 55 3 5n 2 21 DA m do m H Hz Eod Hz o crar 20015 ROOMS us RPM STAT Mx E EE F TEIG SETUP FILES BUTOSTE 20 Recall the send or source room spectrum by pushing the RECALL hard key and locating memory 8 Now push the KEEP H key to keep the spectra and return to the Main menu 72166 13 56 44 W Fall E AWE E MA E SUM KEEF CLEAR RECALL E Hate SEND AWE FAGED LIMEAR SINGLE zB BEBA Dual LIMEHR 2BHz 26k Hz RESET z3 FEB 98 10 19 56 FILTER 14 25 8 Hz L 3 UE Channel 1 s z coe DIFF Ph 98 4 Sn 57 46 TACH Ha SPEED B d hrec all data REM El Hz ROOMS DELETE 21 Return to the Rooms menu by pressing ROOMS Y and enter this source room spectrum by pushing SET gt L and SOURCE M Exit back to the Main menu E 23 FEB 14 81 82 HC HE EC surface volume ETER 140 Us T O L eL RT a at A H AAR AET R e a C a D RT SOR T R R 79 ane N TE yl GATA SET i Hate SEND AWE SPL WERAGED ai r DA AD E Ges cine ioe E Agena e o 2 E 2 LIHEHFE STIWGLE zu Dual LIMEHR 2BHz 26k Hz d i RESET z3 FEB 98 10 19 56 eh r 22275050 4 BE ERES cU FILTER 14 E Q Hz L 3 vE Channel 1 SE Z HORMAL lt S REEL LLL LLL LL LLLLLZ DIFF Ph 98 4 Sn 57 46 REM TACH 6 8 SPEED B a H Hz 5 5 c dotted crar ROOMS
66. R 9 EXPOHEHTIAL 148 Dual LIHEAR 2BHz 26kHz STOP 23 FEB 98 23 22 44 Da RR ER RES ESTEE G7 fait Cad ra O ER SEER a FILTER 14 25 A Hz Les Channel Z of z HORMAL d 45 7 Ee 64 7 ee a Re o3 on a E o o o o o n DIFF Pbs ad T Ens vy ey FEM TACH 9 9 SPEED B d H Hz bod Hz dotted crsr DUUE US Dis WaT U Sun BWwHORM This key permits you to view a displayed spectrum that was tak en in 1 3 octave in 1 1 octave This will sum the 1 3 bands into groups of three to produce the spectrum having 1 1 octave band widths This key will return you to a 1 3 octave bandwidth from a 1 1 octave bandwidth If the measurement was taken in a 1 1 octave bandwidth you may not view it in 1 3 octave bandwidth The 1 1 A or 1 3 B will not appear in the menu This key controls the digital readout of the broadband levels A weighting or Linear Summation shown on the right side of the spectrum by the two vertical bars The actual numeric readout for 2900B TRAINING MANUAL 1 6 SETUSER F Multi H these vertical bars is identified by A for A weighting and for linear summation shown below zr 2 5 265 Be 1 1 1 3 SUM SETUSER note Multi dote SPL 2 S508 ESL LR Dele e a A EE E ele cafa a Tel loo 6 o a da DE m A PONEHTIAL 175 hua LINEAR 2AHz 2Bk Hz TOP 23 FEB 98 23 22 44 70 A ae Zao RTE E a A ISLAS KE o ARANA FILTER 14 z5 H Hz Leo i Channel 1 pre Terre l 42 7 Cee 81 7 SH ws Sar dea bh Nae a A sr
67. RESETS s s INITIAL 1 0 Sia Gen INPUT D clock 12 13 2900B TRAINING MANUAL 6 Then select 20 10k N to activate the 20 Hz and 10KHz fil ters N ie 26 16 23 HORMAL Lex MIH HAR SEL DISPLAY note DETECTA SPL EB mia VEI bores ioi pe EN EXPONENTIAL 14 8 Dual LIMEHR 26Hz 16kHz RESET 12 JAH 33 19 58 59 E iva uie sis AE S uc S Rea op A di FILTER 24 250 Hz Lez za hanne 1 giog Does oq sept e ts A A A AY DIFF Ph 62 8 zns 7 88 Se TACH 6 8 SPEED B a INITIAL j ROOMS vsRPM STHT Mx Spec Mc FILES AUTOSTR 7 Press the SAME O key to assign the 20 10 kHz to channel 2 8 Press EXIT twice to return to the MAIN menu EXIT Selecting an Exponential detector For now keep the detector type set for exponential averaging and the integrating time at 1 8 sec If the 2900B is not already set up for this averaging option see right side of display do so at this time 1 To set these values first press EXIT Then choose DETECTR EXIT X H to enter the detector or averaging menu H R 2012548 Keep Les MIN He SEL DISPLAY note GETEST SPL B ABE 140 e EXF HEHT T DL 1 78 Dual LIHEAR Z26Hz 16k Hz RESET 12 JAN 92 19 58 Bh Foo oh oa m m a 3 93 3 3 2 3 o3 2 9 3 2 3 3 2 2 2 3 1 3 3 3 3 rs n n n n FILTEE 24 z756 Hz Leo a ote 1 oS Le T d RERUMS DIFF Ph 62 8 zns 7 88 care Se O O O I TRCH B a SPEED B i a s s dotted IMITIAL q ROOMS vsRPM STAT Ma Spec F TRIG SETUP FILES AU
68. RY wat me ibe e et ter AA a a R C DE FREQ AA BARAH H4HH a do 1 of 1 NORMAL 28 CENE DTI A R r a SP a a ae Ree A a N Loc TACH 6 6 SPEED 4 4 ah El dotted crar IMITIAL FTZ00M WINDOW BASE Ed UNITS F to enter the Units selection menu 15 OCT 19 31 54 SLM STAND 1 STHHD 2 CROSS INTENSY UNITS FILTER CLASS 2 11 Next let s establish a units label and calibration value for our V accelerometer or whatever transducer you are using Press F SPL B mid eh A E E Dod Fdo JR de v DEUM oU Ro e AC EL dE Ux LLLI QE UL JR I cec Ve pd A decode JL 74 EXF HEHT HL 1 78 TIneut 1 LINEAR ZBHHz ZbBkHz RESET 15 OCT 94 19 23 61 4 Sa a a a ra a a a a a DD A FREL AA HARAH H4HH Channel 1 of 1 HORMAL d 15 3 Loc TACH 6 6 SPEED ALA Be HAHA Z o0mM 1 tama Ba dotted crsr IHITIHL 1 0 HOISE IHFLIT clack COLOR SETUP FILES RESETS 12 For this exercise you will use the acceleration label G s Press name B to create this unit name 15 OCT 19 32 36 SLOPE SAME R UMITS Hoise F mU cal U cal level SPL B mid eh wur xe u c A xo dE OEC e DE Ee ot T uh CET e DR e VR CR Ye JU we at dr Meri EU ee da D EXF HEHT HL 1 78 Tneut 1 LIHEHE 2BHHz ZbBkHz RESET 15 OCT 94 19 23 61 4 a O a A R A se ae ee es em fe Be N A eee ay A in e AEAT ete er eee FREQ Aa HARAH H4HH Channel 1 af 1 HORMAL d 15 3 2 Loc TACH 6 6 SPEED ALA 96 HAHA Z o0m 1 TAGE Ba dotted crsr IHITIHL dE el SFL undet U
69. SPL WERAGED BH ua A RO A A ie TOMUS LINEAR FEPEAT HB HA BT IME Ineut 1 LINEAR 2AHz 24kHz RESET 63 OCT 94 15 82 54 AA Sais a ata la dm a T c GE m A cm RES Te A a we A FILTER 37 E Ead Hz Leo Channel 1 of 1 usTIME d 52 1 A 65 8 44 o A A o l l PHOHS Loc TACH 6 6 SPEED B amp zu o LRL m m o E EROR ANNA O LOL ES i Saki Hz S z brec all data ROOMS ba TACH TACHSET F TRIG ILES Notice that the bTIME label on the left side of the screen has disappeared Autostore is now disabled wae ce 17 46 51 OFF b9TIME delta endstor nate Hotes SPL WERAGED or E e lee au Ja oY A eem flag ate K a Te ca ike el SS Sa a Lead Ed ee ee LINEAR FEPEAT HB HA Ineut 1 LINEAR 2AHz 24kHz RESET 63 OCT 94 15 82 54 AA eS Gat fe a ode Gh ae wie Ga ee AE Rea en EY et ed a a ae FILTER 37 E El Hz Leo Channel 1 of 1 vzTIME d 52 1 A 65 8 40 o ee PHOHS LOL TACH H a SPEED B E Saki Hz i z brec all data F00Mm5 ba THCH TACHSET F TEIG FILES Press EXIT The RT60 register that was completed earlier will be used for the receiving room reverberation time and thus will be included in 9 22 SCREEN SYSTEM 2900B TRAINING MANUAL the Sound Transmission Loss calculation Let s verify that it is the current or active RT60 6 To check this press ROOMS I ne oe 1152121 HOEMAL Lex NIH MAH SEL DISPLAY note DETECTA Hote SPL AVERAGED Bi S R ee ewe IR M ee rca LINEAR FEPEAT DG Inrut 1 LIHEHE 26Hz 29 HZ FESET S OCT 94 15 82 54 5
70. SpE 64 61 TACH 4 46 SPEED B d recall data REM ROOMS 9 29 2900B TRAINING MANUAL 12 Then press the EXIT hardkey to initiate the calculation The new spectrum that appears in the display is the average of EXIT the 3 source room spectra Notice that the word AVERAGED appears on the right side of the display next to SPL m 18 46 11 W Fall B AWE B MA B SUM KEEF mm n zu LA G IL M El oe TA Ha WIT LZ 4c uma Cus r m m al I Z Tr m E H E Al BT eo Re SR reese T g Mn gr tco m B 398 d 47 3 DIFF Ph 98 4 She 57 46 TACH 8 8 SPEED B a recall data REM E ze H Hz ROOMS DELETE 13 Press the STORE hardkey to save the data to memory Note amp that this new averaged spectrum is stored in the ROOMS file STORE as Normal record 8 23 FEB 11 13 17 W Fall B AVE BE HMH amp X BE SUM KEEP 106 a EECHLL Hormal B Hote SEHD SPL AVERAGED LINEAR SI ana Dual LINEAR zBHz 2BkHz RESET 23 FEB 93 14 FILTER 14 25 0 Hz L7 2 S DIFF Ph 98 4 Sns 57 46 TACH 8 8 SPEED B a recall data REM E ze El Hz ROOMS DELETE 14 Now let s average the 3 receiving room spectra together Press B AVG B 23 FEE 11 12 17 U Fall B MAX B SUM KEEP Ae K NR RRR NNT He He NR R 6 ee 0 X X Ere X G9 y CE A EECHLL Har mal i Hote SEND SPL EFAGELD LIMEAR SINGLE zB BEBA Dual LIHEHE ZzEHz ztikHz RESET z3 FEB 98 10 19 55 FILTER 14 25 6 Hz Led WE Chann
71. The last item of interest in the filter menu is FFTZOOM We will delve into this powerful function later Press EXIT to EXIT leave the filter menu Selecting the High and Low Pass Filters The default high and low pass filter setting for the RTA are typi cally 20Hz and 20kHz as can be verified by looking in the appro priate field on the right of the display E ic 23 39 49 Chanls SLM A STANDRED CROSS IMTEMSvY UNITS FILTER CLASS aj wo mom ws 9 mon 9 o 3 3 9 3 3 3 9 3 3 9 3 5 9 3 c9 3 4 3 c3 3 3 c9 3 3 3 c 3 EXF HEHT T DL nEut 1 LI zBHz zBk i RESET Bz JAN Ss i TH KK KRA a rp lx p c p dj arcc FILTEE 16 46 8 Hz Les el 1 gt Ore E Eee hehehe eene DIFF Ph 52 2 Sn 2 43 REM TACH B B SPEED B a 2B D HZ a OFF IMITIAL I o SIG SEH INPUT clock COLOR MLS FILES RESETS 1 In general vibration data of interest tends to be in the lower frequencies Let s modify the high and low pass filters to K reflect this desire by pressing INPUT K a2 igh 23139149 Chanls SLM A STANDED CROSS INTENSY UNITS FILTER CLASS 5 Em M MT T MM SPL B HaHa 3H A A O A A A RR E EXPOHENTIAL 148 Inrut 1 LINEAR 2B8Hz zBkHz RESET 2 JAN 93 2313814 DE 0172712010117 7017217111117 a RR a AA FILTER 16 4A A Hz Les Channel 1 of 1 HORMAL d 23 8 a 37 8 5d r EEN et mol TRL AC Bh a SR poe EE E wer aur de OR lee See cae Pa TRL UTILICE LM E DIFF Pbs be Ens 7 45 REM os TACH a d SPEED 4 4 E z DFF INITIAL C
72. U F 2900B TRAINING MANUAL 4 Press EXIT to enter this filename Notice that the filename and creation date and time appear in the MEMORY file win EXIT dos 15 OCT 22 20 09 create FECORDS disk t Format Memoria Used mi Disk Used Memoria Free 2259984 Disk Free DISK DATE TIME SIZE MEMORY delete rename delete rename mem 5 Press EXIT to return to the Autostore menu Notice that the filename appears at the lower left corner of the display This indicates that it is the active file where measurement records will be stored EXIT 15 OCT 22 26 56 OFF ESTIME delta endstor nate G B BREE z0 S K R RR A eg R a aD e ib dis dc vs GR ace o EXPONENTIAL 1 64 bTACH Ineut 1 LIHEHR 1Hz 18kHz RESET 15 OCT 94 22 17 16 a B WoW KR RN ow R X Ek OR WO RRR R NR NR R R RR NN OXON OX R NR OK XR N NR RRR N N Inn ARAAH H4HH Channel 1 of 1 HORMAL d 95 2 E 71 4 o TACH BH SPEED HL 24 dotted crar F TEIG FILES You are now ready to make by ACH autostore measurements Performing the byTACH Autostore Measurement Verify that the output of the tachometer is connected to the TACH INPUT jack of the Model 2900 Also check that the accel erometer is connected either via a 950B or AD045 adaptor to the Channel 1 input Make sure that your tachometer is turned on and is reading an accurate tach signal from the rotating test article that is below the trigger speed 500 RPM 13 13 2
73. U LINEAR 26Hz 20kHz 3 FEB 32 16 25 16 RUH 1 at PB A iv FILTER 24 254 Hz Leo Channel 1 of 2 HORMAL d 144 A A 1 3 TH A DIFF Fh 92 6 zns 38 61 REM TACH 9 09 SPEED B El E a R Hz Eod Hz doatted crar IHITIHL F SPL MSEC z under under under Under The message Enter Level XXX will appear on the right side of the display prompting you to enter the known excitation level via the numeric keypad For a LarsoneDavis Model CAL250 calibrator the level will be 114 0dB P 5 16 26 22 no euni Ried E oz ba ee Saver dog atid dien Eurer dievai TR dO pl Dod oon miedo dex e op eie Qr N o bo Oe hee rp o oo eei EXPOHEHTIBL 1 2 Dual o EDS zu Hz z kHz RUH a FEB 38 16 25 16 GIS CN THH FILTER 24 25H Hz Leo Channel 1 of 2 HORMAL d 166 68 A oo FR k ee DIFF Ph 92 56 5n 38 60 er TACH Ha SPEED a d e s dotted crar IHITIHL 2 4 2900B TRAINING MANUAL 6 Press the EXIT hardkey to return to the System Menu EXIT Verify the calibration by placing the unit in the RUN mode and turn the calibrator on The level displayed should agree to the level entered when calibrated a 5 16 25 55 SLOPE name SAME R UMI TS Hoise F mi cal U cal level SPL 31 3488 125 KR N R NR R R RRR NR Rh RRR NR RR R RR NR RR R R N NR RKR R RN RRR K RR N N EXF HEHT IHL zB Dual LIMEBR 258Hz zBakHz RUM 19 FEB 93 16 28 24 FILTER 24 258 Hz LS ala O L d d 114 6 146 A o n n nn nnn n Zn gn x 9ccee 4
74. Ue N tay Maw clear NE FEEL A ARRAH ESHH Auto Spectrum D 2 l 3 E Tar ah DO MENCIONAR Eua x iO EIE EN E I A O Base Fresuenc Ab BARRA REN TACH 8 8 SPEED a BE k t FE ar pl dotted crar INITIAL HUG T C WGT 1 28k 2b 26k zB 18k SHHE aRHHGE In the process of making impact measurements it is often necessary to establish an offset between the channel one input range and the channel two input range This is done because the channel two response signal is normally greater than the channel 1 force signal due to structural resonances Select CH2 to activate channel two of the analyzer Next press ARANGE P to activate the range offset BB H1 52 17 Bu zo U 299 U AUTO FA TEST E SPL 6 0060 2 RKR RKR RR O S o ME de ck UR cea NR D CD OD CS Ue LAS D DAL TS A ALCUN URL T A N EXPOHENTIAL 148 Dual IHEHR _1Hz 18kHz RESET Ff JAN 928 01 51 08 TE E NA RA A OR EG Aa ARRAS ESHH Huto Spectrum D d 21 3 a Tar ae T aR day Gain Boe ghee ees a NKE fae hag OE RI R NR cs i a A RM A oe ee a M 6 Base Frees uencuz HB AHHH RE TACH B SPEED B B aa 0004 00m 1 I246 2758 E A hdo INITIAL H S T C WGT 1 28k 2 zBk 1 16k 28 16k SAME aRAHGE 13 Then press the right arrow key once to establish a 10 dB off set between channel two and channel one 14 Toggle CH1 and CH2 to verify on the measurement display the 10 dB range difference Press EXIT to leave the INPUT menu 15 Press EXIT again to enter the MAIN menu
75. Y AXIS U SCHLE U FSET H SCALE H OFSET SV SINHFU SPL 1 2258 3H A A NA ARAS AAN as A EXPOHENTIAL 1 48 Dual LIHEBR 2BHz 26kHz STOP 23 FEB 98 2011312 T AA ao EEEE Ge A A A A AT eee E A oe Gas EEN FILTER 14 25 8 Hz Les r Channel 1 of 2 HORMAL d 49 2 A 81 7 ag Wem dee se gee a OE ELA Re CRT UK RO XC dee se ge 9 wm m s AJEeBBBEBEBEMEmoE So noo om oot Ro RE BIFF Pbs B3 2 Ens 2H AS FEM TACH 9 9 SPEED B d IDEE C LI ELIT E xn H Hz Bak Hz D KK hdo da crar DUUE UZ McSTOP McWAIT McREFT McSTART SameREF SeLEEF zsREEF User selectable zoom factor from 1 to 8 User selectable offset Use the horizontal arrow Keys to shift the window in multiples of 10 dB User selectable zoom factor from 1 to 8 User selectable offset Use the horizontal arrow Keys to shift the window Checking the analyzer battery SHIFT 3 4 To check the analyzer battery 1 Press the SYSTEM hardkey The following message will appear on the upper right side of the display indicating the supply voltage 16 FEB 21 43 47 Chanls SLM A STANDRD CROSS INTENSY UNITS FILTER CLASS ER 162 STE cis Sul dain Soe GUD bd fa Steg HE E CCP NO DEL ga Dube bbe A i oae a we Gatien Cas des des HE as a RN T 0 SUP Flu Mo lts 11 a i Hote TEST 1 SPL 1 4568 T a rz SO ay ey E Sat da A O A OEA A on on O SS qeu ug EXPOHENTIAL 1 8 Dual LIHMEHR 2BHz 26k Hz i RESET 16 FEB 33 20143133 1 581 De a ai EN gate Nr acta E VE case day ve ah abe fe A AA ee Tore FILTER
76. Z Zoom changing vertical and horizontal 3 4 Zwicker Zw Diff 1 8 Zw Free 1 8 Index 2 Model 2900B Training Manual 2 27 98 PostScript error undefinedresource findresource
77. a ED de ee R XD JST GAL Ge eR a a Be 8 FREQ B HnammHz H4HH Channel 1 of 1 HORMAL d 95 2 E 71 9 m LOC l I TACH 6 6 SPEED B amp QG HAHA Z O00mM 1 tana EE dotted crsr IHITIHL Press EXIT to enter this span As discussed for this exercise you would like to capture spectra during the autostore at 20 RPM increments Unfortu nately it is nearly impossible to capture data at exactly 20 RPM steps because of the difficulty to precisely control vari able speed machinery Because of this you need to establish a range for the autostore delta that you would accept a spectrum using the t Amin and t Amax parameters For t Amin you will use 20 RPM What you are telling the 2900 here is that the minimum increase in speed of the dc motor is 20 RPM before you will capture a spectrum t Amax estab lishes a maximum change in RPM that you would accept Normally one would choose a large number such as 1000 RPM to insure that something is captured Setting these delta values is particularly important when testing things like chain saws whereby it is extremely diffi cult for the operator to control the running speed 13 9 2900B TRAINING MANUAL 1 OW U A 13 10 Press t Amin C to enter the minimum tach delta entry field 15 ES zl 21 12 t scale t sean Ganin Xt amax l t inrut Cal SLOPE ANG Tach inrFut Jack B BEBA l ST SE TER E AA E R R A dd A ak abe T R R al Oe EXPOHEHTIAL 1 64 bTACH
78. ana lyzer If the desired reference spectrum has not been stored to the memory do so now by pressing the STORE hardkey then press the RECALL hardkey to bring the spectrum to the display o 2 18 27 Wi Fall E AWE E MAS E SUM KEEP EXPONENTIAL 1 8 Dual LIHEHE 28Hz 28k Hz STUF 23 FEB 98 201131239 FILTER 14 25 6 Hz L 3 Channel 1 eL Z HORMAL d x DIFF Fh 835 2 5n 26 05 TACH BH SPEED B 8 recall data REM xB Hz E DUUE UZ DELETE Press the SHIFT hardkey to activate the Shift Menu This menu will only be active for 6 seconds it will then return to the menu prior to pressing the Shift key 23 155 2114133 R AXIS Y AXIS U SCALE U OFSET H SCALE H OFSET SYSIMFO SPL 1 2256 3H r ie RE O RR E EXPOHENTIAL 148 Dual LIHEBRE zBHz z kHz STOP 23 FEB 98 26011312 FA r A RA A A FILTER 14 75 8 Hz Les Channel 1 of 2 HORMAL d 495 2 H 81 7 54 a TE BIFF Fhz B3 2 5n 2H AS REM E TACH 8 48 SPEED B d NS Bok Hz A Mk Hz dotted crar DUUE UZ C STOP McWAIT McEEFT McSTART SameREF 5SetEEF usREF 3 1 2900B TRAINING MANUAL 2 Press the SetREF O key to assign the displayed spectrum as the reference o 2114133 K AHIS Y AXIS U SCALE U OFSET H SCALE H OFSET SYS IMFO i SPL 1 2258 at r AA TR T NTH A AAA E cat fine T R R 0 A E A i fae VO EXPOHENTIAL E Dual LIMEHR 2BHz 26k Hz STOP ZA FEB 98 201131239 TH r RR RS A RR A AR Dae Tastee fe ee Asal mm FILTER 14 zh Q Hz LS
79. assigned to Key B Beeper Control 1 Press the ER F key 5 EB BEBA ro A RA A A TR E O Gucci iets Seg A Mie N a RR 1 EXF HEHT T DL 1 E Ineut 1 LIHEHE ZBHz 26kHz FESET 19 FEB 93 11 68 30 B Sai Sky Jay Mas vim O A GP ra NL NE CE RTL Sor ub ce a Jun a o e DIN CARN TR FUE FRE He HRREHS HSHH Channel 1 of 1 HORMAL d 33 3 E REM j TACH A SPEED B El Be HAHA Z o0m T 16060 Gee E A datted crar INITIAL T L IHE Su BEA 1246 2406 dani 9688 19768 2 Press one of the following keys to program the beeper func tion 19 FEB 17 23 11 HOWE ALL KEYS OLER ERROK au eM ME M e ac ET AES wet Gach Sa os a Sew Beers t KEYS QUEER ERROR SPL A BABA TE i fas A A RT ant a N saan ume a a WOE OA eh tee ss ge ee OO TE ERES EXPOHENTIAL 148 Input 1 LIHEBR 26Hz 24kHz RESET 19 FEB 38 17 083 pa A E ay dp RA N oT Sie ml TT St AR Gen ET E ite ais ay OBR a fen EEG AA BARAH HSHH Channel 1 of 1 NORMAL 35 9 E 6 6 AB Dus TIIIMITMTI REM TACH 9 9 SPEED Bg a an ada 00m 1 10600 6006 Z A DC output IMITIAL NONE A No beeper signal at all ALL B Beeper signal for a key press an overload condition and an error condition KEYS C Toggles On Off the beeper signal for a key press OVER D Toggles On Off the beeper signal on an overload condition 2 13 2900B TRAINING MANUAL ERROR E Toggles On Off the beeper signal on an error condition Operation of the Noise and Signal Generator Op
80. crar DUUE UZ T 7 7 y 7 T T 3 Press a letter I P to assign where the macro will be stored For this example press the letter K Alpha characters A P will appear across the top and bottom of the display To select the rest of the alpha characters press the Shift hardkey and Q Z will appear A flashing cursor will also appear in the upper right hand corner of the display after the message Enter macro name 4 Begin entering the name of the macro If you make a mistake entering the text you can move the cursor with the left and right arrow keys then press the SPACE hardkey to erase the last character 5 Begin defining the macro by pressing the following keys DETECTR H LIN S A AV TIME H Enter 5 seconds for the detector time EXIT hardkey twice System hardkey Filter G 400line K EXIT hardkey SPACE hardkey R S hardkey 9 2 2900B TRAINING MANUAL 6 Press the minus key This will terminate the definition of nn There are four special Macro keys that can be found by pressing the SHIFT hardkey They are labeled McStop I McWait J McRept K McStart L These special Macro keys are typically used for special applications 23 FEB 19 47 83 1 15 Ip p ss M cc xc c SPL B BREE aj dE LLL ML IS a LLL ERXF HEHT T HL 175 Dual LIHEHR 2BHz zBkHz RESET 23 FEB 398 19 33 12 rar xa RR KR em AAA FILTER 14 25 4 Hz Leo Channel 1 of 2 HORMAL d 23 6 H 8
81. d 34 64 Hz Az BLdBrEl JOB iTE i da In U 25 8 Hz QG Hz 10 BkHz H dotted crar HITEST 5 S FART S AFEA S EDIT CitF4 2 Cz Fd z F3 FZ 12 29 2900B TRAINING MANUAL 12 30 19 Next press S gt EDIT L Use the arrow keys to move to the desired Part field Enter the name of the part for the sound power calculation a3 gua 16 42 87 Power F2 P I F3 HFP F4 FHU note S3TEST 1 7 7 3 Y Y dB El B AH KRN EE AI RO qe A a gt aaa LIHEAR SIHGLE 2H Dual LINEAR _26Hz 16k Hz RESET 03 AUG 94 16 48 53 P ar q q FILTER 14 25 8 Hz 173 POWE 1 d 13 0mm d 19 34 JAG Balm Beg CIIM I a lc E AN A ee ae 33 zu Hz 3l T dBel JOB TEST Loc PART TOP 1909 K R T H R RT cad ea ay AT RAR NN E AREA PO T MT 5 25 8 Hz Su Hz Fe Hz Z A ndotted crsr AITEST SJOB S PART S gt AREA PIT CitF4 2 Cz Fd z F3 FZ Now the name of the last part that you created measured will appear at the top corner of the display next to the job name 13 JAN 91 32 58 Power F2 P I F3 MPP F4 FNU nate S gt TEST FRONT 19777777 i El 92919 SH Xo cff E Di dez EE a Cas ORE cet ae 8 EPA ARA ae Mud LIHEHE SIWG ARR 1 LINEAR 28Hz l kHz ET 13 JAN 98 9 207 18 FILTER 25 315 Hz L AM PD i d 13 0mm 18 44 aga B SH baie vifa R c ay a RR RR dada a ee ee Re a e Ad Hz Az 804dBrli DB TE REM PART FRONT at E Wo G ROCA KR R UX OUR O A A A RR RR OE RR R N AREA POIWT1 E a e crar 25 8 H 506 Hz 18 BkHz E A dott
82. ee e gh net EXPONENTIAL 18 Dual A WEIGHT RESET us MOR 95 01 18 55 TA Tr A AAA ASA EAS FILTER 14 75 48 Hz Leos Channel 1 of 2 HORMAL d 25 A 777 SA c r PHOHS WaT Loc TACH 8 8 SPEED 7 1 2900B TRAINING MANUAL 2 Within the files menu press create A to make a new data Q file A 18 MAR 16 63 33 FECORDS T disk t Format Hemor UseN Jan Disk Used Disk Ho Drive Installed Memoria Free PAZO Disk Free MENDES ISK TIME SIZE DATE TIME HAME CATE MEMORY delete rename mem delete rename 3 You are now being prompted to define a name 8 characters or less for the data file For this example type in VIB1 To do this press the softkey above or below the display To access alpha keys beyond P press the SHIFT hardkey once then the desired letter 4 Numeric entries are entered using the numeric hardkeys on EXIT the keyboard After you have typed in VIB1 press EXIT 12 MAR 16 64 34 A E C D E F a Hemor Used Feo Disk Used enora Free 22099328 Disk Free Enter new name MEMORY CATE TIME HAME CATE TIME MEMORY F Notice at the lower left corner of the display the VIB1 file name appears This indicates that measurement records stored in the future will be placed in the VIB1 measurement file BLUE 16 66 13 HOREMBHL Les HIH HAR SEL DISPLAY nate DETECTE SPL B BREE ae A I ds MESS EI ELE TE a DEI IND RD DEO CE do
83. forms of spectra Normal Leq Min Max SEL and MaxSpec CROSS D This key places the analyzer in a cross channel mode for perform ing Autospectrum Cross spectrum Transfer functions and Co herence measurements This implies a cross channel measurement between channel 1 and channel 2 2 1 2900B TRAINING MANUAL INTENSITY E optional This key places the analyzer in the intensity mode for performing intensity sound power and quality measurements This mode of operation is discussed in detail later in this manual Selection of Units and Calibration In the Units menu you can select either dBuv SPL or define your own units of calibration To select a units type or define a new unit of calibration 1 Press the UNITS F key from the System menu PB 16 88 17 Chanls SLM H STANDRE CROSS INTENSY UNITS FILTER CLASS SPL B ec a r A A RT RO RN EXPOHENTIAL 18 Dual LINEAR z26Hz 28kHz RESET 19 FEB 98 16 65 46 TH r ite ld R RE al W E M Ow De RR wo Wh D A R ee a a ae cade Gl 26 RA FILTER 14 25 4 Hz LS Ja nanne 1 o a r A DIFF Ph 52 8 n2 2 42 REM TACH HG SPEED ALG 25 6 Hz 630 Hz 2H BLC HZ dotted crar INITIAL 1 70 SIG GEH IHPLT clock COLOR MLS FILES FESETS 2 Press the name B key to assign a Units name to an unde fined Units key 19 FEB 16 11 25 SLOPE SAME R UNITS Moise F mU cal U cal level SPL 6 0000 at r E R RR R AN A EXPOHENTIAL 1 8 Dual LINEBR 2B8Hz 28kHz RESET 19 FEB 98 16 05 48 rer pL NO
84. imbalance etc You will not use the X AVG feature for this exercise Please refer to the 2900 User Manual for more details on this feature You have now established all of the parameters necessary to perform the byTACH Autostore measurement Before you begin the test let s create a measurement file where the data records will be stored Press EXIT to return to Autostore menu Creating a Measurement File 1 gt O 13 12 Press FILES O to enter the Files menu 15 SE RH Ii a OFF bsTIME delta endstor note G 6 0000 z0 O sar ar a ae e ea var aa aoa A E E By cal O E ca E e TER of ROR EXPOMENTIAL 1 64 BTHCH InFut 1 LIMNERE iHz 18kHz FESET 15 OCT 94 27 17 10 4B DNUS EE TENTE A A A Be SR E AR e R ae ae TR FEEL Q ARRAH H4HH Channel 1 of 1 HORMAL g 95 2 e 71 4 6h Nal say hs es falta e e deso T vas pa de dd do DA E A O MEME aay ne vel Via OE l l TACH 4 46 SPEED B d 96 0000 zU nM 1 tma Bd doNLed crar IHITIHL bsTACH THCHSET F TEIG FILES Next press create A 15 OCT zz 18 1B8 create FECORDS T disk T Format Menor 19 create e Disk Used Memoria Free ENDE Disk Free Pen DATE TIME DATE TIME SIZE bTACH LOC SIS MEMORY T delete rename men delete rename Type in a name for the measurement file such as DCMOTOR 15 OCT zz 18 47r H B E D E F G Hemor Used z796 Disk Used Hemor Free Sea Disk Free Enter new name HAME DATE TIME SIZE MANE DATE TIME SIZE bTHCH Loc SIS MEMORY 7 I J E L H H
85. kHz ZH FEB 16 04 32 R RT B Auto RE Auto Al note ETEB Hote i SPL AVERAGED 18 n rc on 0 50 A O o LIHEHFE FEFEAT D DG bTIME Lia LINEAR 26Hz 16kHz RESET 26 FEB 938 15 17 55 12 A I nns E 75 4 5 H k Hz S r FT66 DATA RT66 4 226 HHlUa Hi Nr L ER x 6 6464 Bia FEM DIG aR R E RE EE RR RN a H Hz EH Hz d HBEHz A dotted crsr ROOMS lthresh thresh Auto TH SUL LD COTTED edit You have finished the RT60 portion of this exercise At this point the data could be sent to a printer which would yield a graph like that on the display The printout would also include a table that lists the RT60 values for all of the 1 3 octave band frequen cies between 400 Hz and 5 kHz 19 Press STORE to archive the RT60 register 7H FEB 16 04 32 R RT H Auto RE Auto AL note STORE RT S Hote SPL HUEFHGED 159 o JII anil ND lt lt lt s lt lt lt LIHEHE FEFEAT B DG bT IME Dual LIHEHE 24Hz 16kHz RESET 26 FEB 98 15 17 55 12 o PP o E 75 4 a 5 Ell Hz S r ET amp amp 8 DATA r RT6H F276 AWG Hi LAME A n T 0 090 pia REN i z B Ek H A dotted crar lthresh hthresh Auto TH SOLID DOTTED edit Sound Transmission Loss Measurements Sound Transmission Loss measurements and Sound Transmis sion Class or STC measurements are commonly used to evalu ate the acoustical effectiveness of walls partitions doors etc for isolating noise between adjoining rooms This is typically accomplished by placin
86. name SAME E UHITS Hoise F ml cal U cal level Beer mh meme ehe nee nne er 6 9009 E HT IHL A hrut 1 LINEAR 1Hz 1BkHz RESET 18 MAR 94 17 11 21 re E NR RA FREQ DD ARRAHZ HS8HH Channel 1 of 1 NORMAL d 15 3 pa G o R E aa Rae UR de cap DEC Ue e S DEC 4E Se Re ee det we Ge a UN ee S ORC Ee E ea IT 79 B TACH BH SPEED ALA QG HAHA Z00NS 1 2506 0060 Z A dotted crar WIE dE el SPL IE under undet undet Under Under 7 8 2900B TRAINING MANUAL Calibration EXIT Calibration values of the accelerometer or any other transducer can be entered in several ways in the RTA The easiest way is to enter the sensitivity or calibration value directly from the cali bration paperwork that came with the transducer In the case of an accelerometer this may be a certain number of millivolts per g mV g 1 If the number was 10 mV g you would enter this by first pressing mV cal F G B mid J6 E EXPOHWEWT IAL A Ineut 1 LINERE 1Hz 14kHz RESET 18 MAR 94 17 11 71 T A ec a ae NN FREQ HA ARRAHZ HSHH Channel 1 of 1 HORMAL d 15 3 B 12 86 DE TACH H H SPEED ALA QG HAHA zD UM 1 2500 0060 Z A datted crar UIEi dE el SPL G under undet under Under Under 2 Atthe Enter mV unit prompt type in 1 000 E 01 using the numeric keys on the RTA keypad use the Shift key then key to enter a io 23 54 12 iB eem e ehh rer rn m or n n n n n n Enter mul unit 1 888 E 102
87. nnel 1 o AL ALL PLOT muni 113 BB d OFF OCMOTOR Press EXIT Another useful way to view byTACH autostored data is by using the vsRPM graphics display feature of the Model 2900 This feature allows one to view either frequencies or orders in an amplitude vs RPM format 1 2900B TRAINING MANUAL Press VSRPM D to enter the vsRPM Graphics menu 16 SET 14 46 36 SL F elevel TAGERES s SFHM VIDEO MARIS note WIDTH SOURCE IS TACH IHPLIT 117 7200 EXPONENT L HL 1 64 InrFut 1 LINEAR 1Hz 14kHz OCT 94 22121135 C FREGUEH R PEH LEWE G E y ia a I tl Gi Lm m m m un cqn JcJe00c07m s o3 am Hl TIC HIC Ren IT n L kek Kh Ke Kek Kk Kek ZT ma ru Er zu m ams end DCMOTOR STATUS HIDE TACHSET B RDER REDRAW PEH The data that is displayed in the vsRPM graphics displayed is the data that you just acquired during the vsRPM autostore measurement of the de motor run up If the hori zontal scaling is different that the 500 to 3000 RPM t span that you used to acquire the vsTACH data you ll need to modify the X SPAN To do this press X SPAN D to enter the x axis scaling entry field 16 SEL 14 46 36 SL F elevel TAGBARS SPAM VIDEO BOARS note WIDTH H 2 OCT 94 22 FREGI Ea y el IE IT n TZ A Em EmEEREEEEI 4 zi ma ru m Al m ams end DCMHOTOF STATUS HIDE TACHSET B RDER REDRAW PEH Type in 00500 03000 into the LOW HIGH e
88. notice the MAX spectrum on the left This is a spectrum showing the maximum value that occurred in each 1 3 octave bin during the time of the test The overall MAX value on the right of the display is the summation of all of the MAX bands 19 FEB 12 45 01 NORMAL Les MIN MAX SEL DISPLAY note DETECTR Gs SPL 11 1958 106 D RA O E e e TE A EA ee E E R RR EXPOHEHTIAL 1 Dual A WEIGHT STOP 19 FEE 9B 12 41 25 oon or s on n 5 5 5 hc 5 5 5 5c 5 o FILTER 14 25 8 Hz L4 Channel 1 of 2 MAXIMUM d 35 6 P 182 1 ZEE o e e n 6 I DIFF Phs MGT lt ne REM TACH 8 8 SPEED J B H Hz poh Hz B dotted crar POPCO ROOMS esRPM STAT Mx Sper F TRIG SETUP FILES AUTOSTR 4 19 2900B TRAINING MANUAL 4 20 5 Last to view the SEL during the runtime press SEL E You will notice the SEL spectrum normalized to 1 second on the left and the overall summed SEL value on the right of the display 19 FEB 12 45 58 NORMAL Lea MIH MB SEL DISPLAY note DETECTE SPL 11 1958 166 AAA AAA a x x EXF HEHT T DL Dual A WEI GHT STOF 19 FEB 98 12 41 25 AI P din a E oe A Eia do 5 Ez FILTER 14 25 Q Hz Leo Channel 1 of 2 SEL d B 104 3 E 0 0 0 o 0 t e ne em eem Ex DIFF Fhz7 uaT Sn REM TACH B B SPEED B a H Hz Eod Hz A k HZ a dotted crar FORFCO ROOMS usEFHM STHT Mx 5rec F TEIG SETUF FILES AUTOSTR Defining macros Macros The operation of the analyzer can be simplified by the use of the user defined ke
89. o deas a a AD EC UE o ies Vo Dd et des A E A A OO Ee OR dee RC QOL EXPONENTIAL 18 Ineut 1 LINEAR 2BHHz zZbBkHz FESET 15 OCT 94 19 35 44 ae ELE freue Dou e wo Me T cx 0 Tes D amo gm AA E ak Sal a SEL D GRE DAD GL OE EL Me Ten 9 Re qm ON TRO EDO me FREQ DD ARRAHZ H4HH Channel 1 of 1 HORMAL d 15 3 B 2 L C TACH 6 8 SPEED 4 4 BA HAHA zD UM 1 Sada ad dotted crar IHITIHL dE oU SPL Cs under undet under Under Under 17 Next let s enter a calibration value for the accelerometer For V this test you will use the manufacturers specification of the F accelerometer sensitivity of 10 mv G Press mV cal F to enter the mV cal entry field 15 OCT 19 37 16 SLOPE name SAME E LUHITS Hoise F mU cal U cal level OCT 19 37 16 SLOPE name SAME R UMITS Noise E B mid eh mo Fae et duc SES SED aa a BE eS Eh ae UR wr Rr NP dac OLI NY HEC EC EN CEP DET TER CLAU RC PRO TNT ac RU Se HEN TER AA as AE ae e EXPONENTIAL 18 Ineut 1 LIHEHE zBHHz zbBkHz RESET 15 OCT 94 19 36 76 ae Qoi ce Rew Be ela ED ES ED eee V uM Deb Jac Tw a EL OO deb ES RD NN SE RC Ue Jac Dur UE C DER JE ENGEL S CUNT REEL FREQ DD ARRAHZ H4HH Channel 1 of 1 HORMAL d 15 3 E 2 ED i TACH BH SPEED B a QG rim zD UM 1 tam aa dotted crar IHITIHL dE el SPL G under undet undet Under Under 13 5 2900B TRAINING MANUAL 18 Type in the accelerometer sensitivity value For this exercise type in 10 mV G as 1 00 E 01 15 cre 19 38 38
90. pe C LL i BIFF Pbs 65 7 Ens 5 794 REN ai TACH H B SPEED B B 5 8 Hz amp 3H Hz zB BEHz dotted crar POPCO 1991 1ne 2HHline 466 line 2001 1ne FFTZOOM WINDOW BASE Bd Press EXIT to return to the SYSTEM menu 4 15 2900B TRAINING MANUAL 5 Typically for Sound Pressure Level measurements one would use either A or C analog weighting filters when gath ering data For this example let s enable the A weighting fil ter Press INPUT K to enter the INPUT menu area AB 18 26 17 Chanls SLM A STANDERD CROSS IMTEMSVY UNITS FILTER CLASS E B piana ra EAR zBHz 2BkHz RE EB 98 18 18 38 aH K RR OK w X X Go X x x X X amp Ww w XE X 4 amp OW X N k wo w X E OE 4 x EX OX NR R R FILTER 14 25 Q Hz Leo Channel 1 of 1 HORMAL d 34 H 46 1 eh r D LIUM ET ILT T m BIFF Fh Bb r n Fa ad REM TACH H B SPEED B B Eod Hz A k Hz dotted crar I 0 clock COLOR MLS FILES RESET S L 6 Within the INPUT menu press A WGTT I to activate the A Y Weighting filter uc o s MOON T RA RH TEST FL B Bla 140 DA A ETSI cals en i Qua AZ Cat al A E SILA san RL RT R EXPOMENTIAL 18 Inrut 1 LINEAR ZB8Hz Z WkHz RESET 19 FEB 938 10 18 35 asi LC LL LLL c c des T 8 FILTER 14 75 8 Hz Leo i Channel 1 of 1 NORMAL d 34 2 H 46 1 GE r oo die NN R RE MEN cake R iy om RR Sony Cat ER RTE ie A R CR at XE ids can ge vir OM A AE DIFF Fhz Br Sn Fa Bq REM TACH BH SPEED B a A k Hz d
91. r par RM Rc P e ao a T MO MP DIFF Fh 65 r n Fa ad REM l TACH Ha SPEED Bg d S H Hz Bae Hz TH ore L doatted crar POPCO FOOMS usEPH STAT Mx Spec F TRIG SETUP FILES AUTOSTR 4 17 2900B TRAINING MANUAL 15 Press SUM E to enable the linear summation feature At the U right of the display you will see a sigma symbol followed by E an sign 19 ane 12 19 25 141 143 SUM SETUSER note Multi PL B BeBe 140 xg RR NR R TE O RR RR RR N a Ra N RR N NY RR N EXPOHENTIAL Ineut 1 LIHEAR 2BHz 26k Hz RESET 19 FEB 938 12 16 26 Bh E E cr ceci ca Oe Pa a Ae 4 75 4 AD ie Lhanne S T d 34 2 46 1 EA r eo R E AE o RO E RR AA A ERA A AA R o R BES DIFF Fh LR 5 3 REM I TACH p a SPEED B B Zoe z z z dotted cram POPCO DiS WaT WW SUM BWHORM 16 Press EXIT to return to the Main menu EXIT Sound Pressure Level measurement To make a Sound Pressure Level Measurement 1 Press the R S to initiate a measurement Notice on the dis RESET play you will see an A Weighted 1 3 octave band spectrum R S that is being integrated over a one second duration Notice also that the summation value at the right is showing numer ically the overall Sound Pressure Level summation of all of the 1 3 octave bands 19 DEE 12 42 28 MORMAL Lea MIH MB SEL DISPLAY note DETECTE TACH 8 8 SPEED B a a E L n BH Hz nm ROOMS us RPM STAT Ms Spec FS SETUP FILES AUTOSTR dotted crzrm 4 18 O W 2 2900B TRAINING MANUAL
92. small sound levels such as outdoor night measurements quiet products or quiet rooms demand the use of a sensitive microphone Higher sensitivity on a microphone is acheived by using a looser diaphragm In general larger diameter microphones are more sensitive than smaller microphones Basic Acoustics FREE FIELD MICROPHONE Measuring in a free field Testing to IEC 651 standards Europe amp Japan Noise source is clearly identifiable Microphone pointed at the noise source Free field compensates for disturbances in sound filed SA U Basic Acoustics 4 3 2900B TRAINING MANUAL 4 4 RANDOM INCIDENCE Used when measuring in a diffuse field Use when testing to ANSI 1 4 standards Used when location of noise source is unknown Responds uniformly to sounds arriving from all angles at the same time Characteristics very similar to a pressure microphone Basic Acoustics RANDOM INCIDENCE MICROPHONE If random incidence microphone is used in a free field microphone should be angled approximately 85 degrees to the sound source Otherwise the resultant measurement will be overestimated Basic Acoustics 2900B TRAINING MANUAL MICROPHONE RESPONSE Free field microphones compensate for self created disturbances in the sound field Random incidence microphones respond uniformly to sound regardless of the location of the sound source s dB Free field Random Incidence 1000 500
93. that the right side of the display reflects the averaging options that we ve selected Now we re ready to take real vibration measurements zl MAR 15 45 35 LIH S LIH R EXP EAPO H COUNT S COUNT E Al TIME LINEAR SINGLE 28 60660 in yA rci I LITE m 2 Ine Mk Hz RESET 71 MBR 94 16 45 69 1Bm ge de Sar ta mo See UR MA URP REO R ARR BE ae teh dee ER RKR D ak Re E E CE PRO tee Se XS TRU CRT DUELO UND ORC ISO ARR ae we gt BB HnammmHz HS8HH Channel 1 of 1 NORMAL d 93 1 65 5 36 fie LR StS a A 0720117702771 717212 EE TACH 6 6 SPEED B E Ge aaa 00m 1 2500 6006 Z A dotted crsr LULE 5 Press R S to begin the measurement process Use the up and down arrows to optimize the range setting as we did during calibration a JAN Be 12 41 LIH 5 LIH F EXP ESF U HM COUNT S COUHT R AL TIME I G 28 000A 14 core i pP T EE LEE Mes ERAI E qp PE LIHEHFE SIHSLE zu DG i Ineut 1 LIHEHE 1Hz 1BkHz i STOP HS JAN 93 99 115 22 FREQ 159 37 56Hz HSHH Chann 1 of 1 NORMA d 37 2 TACH 9 9 SPEED Bg d dotted crar After 20 seconds the measurement is complete At this point you could choose to save the data print it clear it or take it over again A very powerful feature of the RTA is the FFTZOOM feature FFTZOOM allows one to apply the full FFT resolution in the current case 800 lines to a small frequency range This is partic ularly useful if one is interested in acquiring detailed frequen
94. this exercise Please refer to the 2900 User Manual for more details on this feature As established earlier you will acquire data from the dc motor plate as it sweeps up runs up in RPM You first need to let the 2900 know that you want to trigger the autostore when the speed RPM reaches 500 RPM as it sweeps up In other words you want the autostore to trigger on the posi tive slope If you were doing a rundown measurement you would establish a trigger on the negative slope Press SLOPE G and toggle through the choices until STORE SLOPE is chosen 15 OCT 21 54 21 t scale t sPan t amin t amax t inPut X cal ETE Bg A AN RNA L A Haec He Ge Tach neue Jack B aid l ST LE dioc a Be tae N E N RR nd C et tale o a a ca TE R ES EG a a E R ES E EL C E gd EXPOWEWT IAL 1 64 bTACH Ineut 1 LINEAR 1Hz 14kHz FESET 15 OCT 94 28 11 27 44 A a A a ee FREQ AA HnammmHz H4HH Channe 1 1 of 1 HORMAL d 95 2 a 71 8 m POE e TACH H H SPEED a Bn maa 00m 1 DEBE an dotted crar IHITIHL s5scale s sran s amin s a4max EHDHE f RADAR m X AVG is used to average out the errors in the tachometer signal that might be caused by DC jittering DC jitter is caused by vibrations on the surface of the device that the tach signal is coming For example someone is using an opti cal pickup to capture a tach signal on a rotating shaft which 13 11 2900B TRAINING MANUAL EXIT is vibrating due to looseness
95. this note will be stored along with the data It is important to remember to update the note field each time a different measurement is taken Note that this note will be stored with all future measurements unless modified for each measurement From the Main Menu locate the DETECTR H key The selection of choices of averaging types in this menu will be different depending upon whether Octave filtering or FFT has been selected See Chapter 2 for details on filter selection 1 Press the DETECTR H key E BET 15 15 41 WORMAL Lea MIH HAR SEL DISPLAY note DETECTE Hate TEST 1 FL 1 1456 TH CUM a E e AE e Ea eral aby wat TENUERE RR NS A AA EXPOHENTIAL 16 Dual IHEBR 2BHz 26k Hz STOP mi OCT 94 14 35 88 54 fa Sas a N N 267 79T 3 A A A ai N FILTER 1 MI Hz Les Channel 1 of 2 HORMAL d 15 7 B 5 a AB L HI FH HS Bd 3 LOC TACH 9 9 SPEED B d 15 A A E A A NA A ntm e chk Hz Hz datted crar IHITIHL E nms uzkEFHM STHT Hx fhe F TEIG SETUP FILES AUTOSTR 2 Select the desired averaging method by pressing one of the following keys Averaging type Octave Filters Linear Single seconds Linear Repeat seconds Exponential seconds Constant Confidence with Exponential Averaging 2900B TRAINING MANUAL BT LIN E Constant Confidence with Linear Averaging AS DU 15 15 32 LIH 5 LIH F EXP BT EXP BT LIH Al TIME Hote TEST 1 1 7458 EXPOHNENTIAL 1 6 Dual LIHEHE 2AHz 26k Hz STOP 63 OCT 94
96. upper band edge 5kHz C 5kHz upper band edge 2 5kHz D 2 5kHz upper band edge NOTE When performing a baseband analysis if the selected full scale frequency is gt 10kHz using two channels the analysis will not be performed in real time 6 Press the FFTZOOM M key to select the desired Zoom fac tor 1 52 17 03 19 1lrloct l doct lona short reverse SPL 41 5688 ro KRSR NRW N R NR RR KNN A OO NR R Se EXF HEHT IHL zB 1 Ineut 1 LIHEHE ZBHz 26kHz STOF 19 FEB 98 17103 0603 O A LE he FRE He BARRAHAZ H444 Channel 1 of 1 HORMAL d 47 9 B 65 4 TACH BH SPEED B a 1 x U pres IMITIAL j FFTZ00M dotted crar WIHCDOW BHSE EBEd 2 9 2900B TRAINING MANUAL 7 Select the desired Zoom Factor 1 through 512 by pressing a key A K Your selection will appear below the frequency axis of the display 19 FEB 17 09 45 1 2 4 8 16 32 64 SPL 6 6000 ro E O OS E ON OR O EXPOHENTIAL E Ineut 1 LINEAR 28Hz 28kHz RESET 19 FEE 98 17 88 38 JB ecce I a El Ae HARAHZ HSHH Channel 1 of 1 HORMAL d 33 3 6 6 3B A E HRS Nos R NER ASA SEINE cie cur AR A RR RN SEP ES 28 REM TACH 8 8 SPEED 8 8 an A dotted crar INITIA BRSE Hz 8 Press the EXIT hardkey to return to the FILTER Menu EXIT 9 Press the EXIT hardkey to return to the SYSTEM Menu I O Communications Selecting a baud rate 1 Press the I O I key from the System menu Y B 16 88 17 SChanls SL
97. will be turned on Typically used in conjunction with the ON RUN C function LEVEL P Level is used to set the output level of the noise generator The noise generator output is located on the top of the instru ment identified by the label source output located on the back of the instrument This output is typically used to drive a loud speaker for room acoustics Option 11 Signal Generator The OPT 11 Signal Generator provides swept sine with tracking filter and feedback level control dual frequency swept sine and a pulse generator in addition to the pink and white noise provided by the OPT 10 Noise Generator Also there is an autolevel feature for use with the pink noise to assist in equalizing the noise level in a test room 2 15 2900B TRAINING MANUAL Press the SIG GEN J key from the System menu agar 16 83 17 Chanls SLM A STANDERD CROSS INTENSY UNITS FILTER CLASS SPL EB ma 99 L ESPOHENTIAL 14 8 Dual LIHMEHR 2BHz 26k Hz RESET 19 FEB 33 16 65 46 IIH FILTER i4 25 8 Hz Les Je ranna 1 B ue a He D DIFF Ph 52 28 Sn 2 4z REN o TACH Ha SPEED B d EET z doatted crar 516 GEH COLOR MLS FILES FESETS 23 0 H IHITIRL INPUT clock Select the desired spectral content by pressing one of the fol lowing keys ae FEE QS 41 34 OH OFF OHM RLUHM OFF RUH ATT gt ATT SPL B amaad 190 ERER O A EEE E RAE TEE e Exi uinum EXPOHENTIAL 148 Dual LINEAR 2B8Hz zBkHz RESET 26 FEB
98. zH Em Ineut 1 LIHEHE 1Hz 18kHz FESET 63 JAH 92 995 2295 d FREQ HE AAR Channel 1 of 1 HORMAL s 152 9 E 125 1 176 Be a a A ES O CUP LE ENS JUS DEN decre Uere iia BE iB TACH Ha SPEED B d pi S solid crzr IHITIHL dB vU SPL G under under under under Under Press the undef L to edit the label 2900B TRAINING MANUAL 7 Press SHIFT then CLEAR to clear the label Type FT S Then press EXIT to enter the new label B3 de QS 325 97 H E E D E H 5 F LIN e El Input 1 LIMEAR 1Hz iBkHz RESET a3 JON 928 06 34 26 1 4H de Gas rs a fora dir Wires cop da Ges as Pear a a e els ges E A Jal CRAS eZ FRE AG AAAH HSAA Channel 1 af 1 HORMAL s 152 9 E 172H5 A A Gabe Tah Sede Gielen caus Ga Shs ARS R PEM l l TACH 6 6 SPEED Bg d pi x solid crear IHITIHL I J E L IN H F 8 Notice the newly created label FT S at the bottom of the dis play az A Aes 325 4s SLOFE name SAME EUNITS Hoise F mU cal U cal level 1 IS 8h ie aes TE eae he lie 01 Saks Ea R ame tut aR ITI 201217271173 0711071171 071 LIHEHFE uer 2H Em HEUL 1 LIHMEHE 1Hz 1 kHz SE H i JAN 98 09 1 45 cu A Ses ae A a ca wie E A AS e Mae ATE Sen NO DA dae ins uh IR eta uu DES le NO ee CE FE 3 He HRRHS HSHH Channel 1 of 1 HORMAL s 152 9 E 125 1 1zt i ART aoe a E227 RA Res TACH Ha SPEED Bg d dE E t solid crzr IHITIHL dB vU under under under Under 9 Press FT S L to activate the label az an
99. 0 Basic Acoustics CONDENSER MICROPHONE grid cap diaphragm air vent 3 electrode insulator back plate conductor Basic coustics 4 5 2900B TRAINING MANUAL LS MICROPHONE TYPES Condenser microphones requires a polarization voltage Change in capacitance between diaphragm and charged backplate is proportional to change in sound pressure Prepolarized electret microphones requires no polarization voltage Uses a pre charged foil to detect change in capacitance which is proportional to a change in sound pressure s Piezoelectric microphones sound pressure causes a deflection in piezoelectric crystal This generates a charge proportional to sound pressure Dynamic microphones uses velocity imparted to diaphragm by sound pressure to move a coil through a magnetic field This induces a current proportional to sound pressure Basic Acoustics LS HOW A CONDENSER MICROPHONE WORKS Sound pressure deflects the diaphragm which causes a change in capacitance between the diaphragm and electrode backplate Change in capacitance is converted into an electrical signal by maintaining a constant charge on the electrode via a polarization voltage Advantages good acoustic sensitivity good frequency response low self generated noise low sensitivity to mechanical vibration Disadvantages fragile diaphragm easy to damage susceptibl
100. 0 TRAINING MANUAL Measurement Considerations sees eee eee eee 12 10 Measurement Techniques a IIo sea REPE Eget dius 12 11 Fixed Pomt or oca na ira 12 11 Setting up the Model 2900B for Acoustic Intensity Measurement iaa 12 12 Selecting an Exponential detector ooooocccccnccononnnonccnnnnnnnnos 12 14 IO RS RST 51T Tee RT dd 12 15 Programming remote control keys occcccconoonnncccnnnnnnnnnnnnno 12 17 Creating a measurement data HIG esse 12 19 Normalization of input channels eee eee 12 21 Naming a job part andara ia ad 12 22 Selecting a linear DeteetOf once ge isis 12 23 Performing a measurement ooooonnnnnncnnnnnnnonnnnnnnnnnnononinnnnnnnnnnnonnnnos 12 25 Chapter 13 Autostore byTACH vsRPM Display and Order Trac king 13 1 Index vi byTACH Autostore Measurements esse eee eee eee eee 13 1 Setting up the 2900 Measurement Parameters 13 2 Setting the byTACH Autostore parameters eeeeeeesesse 13 7 Creating a Measurement Pile aci 13 12 Performing the by TACH Autostore Measurement 13 13 Viewing the byTACH Autostored Data sss sese 13 15 REVES a dai Maat 13 16 Post Process Order Tracking siii ici 13 19 Reak me vsRPM Grapes naaa ia 13 20 Real time vsRPM Order TrackINg ooocccccccccnnonnoncnnnnnnnnnnnnnnos 13 24 Introduction to LD Real Time Analyzers RTAs Welcome to the Larsone Davis Analyzer training manual This manual is desi
101. 1 8 Dual LIHEHR 26Hz 26kHz STOP 25 FEB 98 23 22 44 Te ee WEE cunc c nu AR FILTER 14 25 4 Hz Les qa EM Ese A oe ka A HT TE A DIFF Ph 84 7 Sn 22 22 REM a TACH 4 4 SPEED A A E ay x dotted crar DOUE UZ Dis WGT WW SUM BWHORM V SUM J NO WGT I A J C K USER L A M C N USER O 2900B TRAINING MANUAL This key give you the vector sum which displays the square root of the sum of the squares between channel 1 and channel 2 spec trum T BR 23136141 1 1 173 SUM SETUSER note Multi Hate SPL Z Sob EXF HEHT T QL 149 Dual LINEAR Z2BH 2HkHz STOP 23 FEB 98 23 22 44 FILTER 14 25 6 Hz Lora a Channel amp of z ORAL DIFF Ph 84 7 Sn 22 22 TACH 0 5 SPEED ALA dobted crear BuWHORM REM 3 Press the Dig Wgt I key to access the weighting menu Hate SPL 2 2506 EXPONENTIAL 1 8 Dual LIHEAR 26Hz 26kHz STOP 23 FEB 98 23 22 44 FILTER 414 25 8 Hz L 3 S EX De a DAL DIFF Ph 84 7 Sn 22 22 TACH 8 8 SPEED 6 4 dotted crar EWH SER 23136141 141 143 sm SETUSER note Multi 4 Press one of the following Keys to select the desired display weighting Evi 19 35 84 Zu FREE Zw DIFF SFL 1 9258 Bl te eee eene EXPOHEHTIBL 1 3 Dual LIHEAF 26Hz 26kHz STOP 16 FEB 95 13 88 33 TH r Bethe es EPI Sa ee ee et ae we Oe ee FILTER 14 25 A Hz Le 3 l E Channel 1 Ps z Dor ME 56 O DIFF Ph 81 9 5n 18 32 REM E TACH 8 8 SPEED 4 4 This key returns the disp
102. 1 NORMAL d DIFF Phe WaT shi TACH BH SPEED B B dotted crar 116 38 r REM JB ROOMS 12 Within this menu you need to choose a detector time inte erating time that would either simulate a slow or fast detec tor rate If one wishes to simulate a fast detector rate then 1 8 D seconds should be selected For a slow detector rate 1 G second is the choice For this example we will use a slow detector rate Press 1 G 13 PRE 12 16 15 1 64 1 32 1 16 1 2 1 4 1 2 1 z FL EB ca 140 DE i Mab R RR RR aa RA RR KR RR AA RR oe EXPOHENTIAL E Ineut 1 LINEAR ZEHz zBkHz RESET 19 FEB 98 18 33 13 ai r his ara iis E E E E AE E RR E NR ET FILTER 14 75 4 Hz Leo Channel 1 of 1 HORMAL d 34 2 A 46 1 15 r Irc gZ RT RN N 28 RT tw ab C Ra aa A N N DIFF Fh GB r cn Ad a E TACH Ha SPEED Bg d e z z S z L dotted crar F FCU d a 16 Az ed 128 256 13 Press EXIT to return to the MAIN menu 14 During the measurement we will want to view the overall summation band for the Sound Pressure Measurement Press DISPLAY F to enter the Display menu 1 565 12 18 15 WORMAL Lea MIH MAK SEL DISPLAY note DETECTE PL EB ma 140 Xa Tic RR A RR NO ee S EXPOHENTIAL Ineut 1 LINEAR ZEBHz z BkHz SET 19 FEB 93 12 16 26 ai R ci A e im ado Roe fk a ELTE MA du VR UE cre R Rr AIL f R de Ma ns oe LE UE FERUNT o U EVEN 9 R N DR COSE cae FILTER 14 75 4 Hz Leo Channel 1 of 1 HORMAL d 34 2 H 46 1 BH
103. 2 28 A 24 2 1 29 ABR EBV MT WE sss A O pogo a Z 3 6 1 1 37 506 d mni 3 7 1 56 HHA LOC a HS 13 2 1 62 2992 Se TEIL PUEDE amp B amp 194 4 1 75 002 56h 2909 RPM 2162 crsr ad CCMOTOR STATUS HIDE TACHSET B ORDER REDRAW FEH CHANNEL FEEL You are currently viewing the following frequency bands in the vsRPM mode 12 5 Hz 25 0 Hz 37 5 Hz 50 0 Hz 62 5 Hz and 75 0 Hz To change these values so that you can view other frequencies first select a frequency that you wish to modify For example if you would prefer to view the 200 Hz frequency band instead of the 75 Hz band you can make this change by first pressing the numerical PEN key associated with the 75 Hz frequency In this case it would be PEN 06 Press the numerical hardkey 6 to activate PEN 06 16 e 14 55 11 SLOFE alevel TAGEARS s SFHH UIDEGO pH LS note WIDTH HR SOURCE IS TACH INPUT ES a G 117 7266 CRT PPP A de EXPOHENTIAL bTHCH R a iga InFut 1 LINEAR 1Hz 1 MkHz SANA STOP 15 OCT 94 22 21 38 4H uS oem NTL root Mh PA PEH LEUEL C FREQUENCY i 5 K ni 46 6 1 12 28 Z B2 24 2 1 5 ABR A AA OA 3 03 6 1 1 37 566 4 mni Zr 1 56 666 Loc a HS 13 2 1 62 288 Old od Pee PII TTE E amp B amp 19 4 1 T5 Aaa 56h 2909 RPM 2162 crsr Sd CEMOTOR STATUS HICE TACHSET B ORDER REDRAW FEH CHANNEL FEEL Then press FREQ P to enable the frequency modification mode 16 DE 13 43 32 SLOPE aleuel TAGBARS X 5PHH VIDEO ATARIS note WIDTH F
104. 25 8 Hz S73 WE Channel 1 s Z SEE DIFF Ph 89 6 Sn 38 83 TACH 9 9 SPEED B d doatted crar ELAY REM R Hz Bd Hz a E ROOMS SINE PIHK WHITE PULSE You may also need to adjust the output level of the ampli fier speaker in order to insure that all of the frequencies of interest are being excited equally The spectrum displayed on the RTA should be fairly flat within this frequency range The output level of the speaker amplifier should also be loud enough such that there is a significant difference between the background ambient level and the excited level for each frequency of interest 9 6 2900B TRAINING MANUAL EXIT RESET R S 6 Once the desired output level and input gain have been achieved press OFF B to turn off the noise generator 28 FEE 12 29 11 ON OFF ON RUM OFF RUH ATT ATT 98 DIFF Ph 89 B Sn 30 83 TACH 8 8 SPEED B a pak Hz A EKA dotted crar SIHE FIHK WHITE FULSE DELAY 7 Press EXIT to return to the System menu 8 Press R S to stop the measurement Establishing the Averaging Parameters for the RT60 Measurement EXIT The RTA utilizes the built in Autostore capability when making RT60 measurements Before enabling the autostore feature the desired detector needs to be established Typically one would use either exponential or linear repeat averaging for this type of test For this example you will use the linear repeat detector 1 Press EXIT once to en
105. 2900B TRAINING MANUAL repeat the dc motor run up test using the Real time graphics capability of the 2900 1 Press EXIT to return to the Autostore display menu 2 Press KEEP H to get back to the Autostore enable menu 16 OCT 16 49 36 ll Fall E AWE E HAs vsEFM KEEF 26 KEEP Hotes B 6268 EXPONENT L HL 1 64 Ineut 1 LINEAR 1Hz 1i kHz FESET 16 OCT 94 16 45 59 FREQ 25 4686H gt H4AA Channel 1 of 1 HORMAL d 59 6 Z5 Y TACH 366 2 SPEED 4 4 brec all data H Freu H Next nate Hotes B 6268 IS OS AN RR A AE AN EXPONENTIAL 1 64 Ineut 1 LINERE i1Hz 18kHz FESET 16 ge n 16 46 59 TACH 366 2 SPEED B B dotted crar F TEIG FILES UU ESTACH THCHSET Notice that the bTACH label is removed from the left side of the display 4 Press EXIT to return to the STAND1 display menu 1 Press vsRPM J to enter the Real time vsRPM graphics dis play 16 SRL 16 51 64 WORMAL Lex MIH MAH SEL DISPLAY nate DETECTA Hotes B 6268 N Rp theo ite Gar teh des Se ia RC AO o Be ee SE N N R Re ee ae A A E K TR ELE NAR d S 9 EXPOHENT I AL InrFut 1 L HE 1Hz2 16kHz RESET 16 OCT 94 16 48 59 w FREQ z5 HHdBmdHz H4AA Channel 1 of 1 HORMAL d 59 6 Br TACH 366 2 SPEED dotted c TEIG SETUP FILES AUTO The measurement parameters from the byTACH autostore are still active and will be used for the Real time vsRPM measure ment Thus there is no need to modify the parameters Let s do a live fr
106. 4 56 DRAW 1 DEAN 2 START END DELTA Hotes SPL B 1668 EXPONENT L HL 1 8 PREAMP LINEAR 26 29 HZ RES 16 OCT 94 63 03 25 FILTER 14 25 6 Hz Channel 1 of 2 HORMAL WATERFALL PLOT START baal EHD mna DELTA B i OFF START E Selects the first spectra in sequence that will be displayed END F Selects the last spectra in sequence that will be displayed DELTA G Selects the incremental record number between displayed spectra Upon pressing anyone of these keys the following message will appear W FALL sXXXX eXXXX dXXXX and instead of pressing each individual key listed above you may edit all the display parame ters at the same time by entering the numbers with the numeric keypad and the horizontal arrow keys 16 OCT 63 03 49 116 B T d EMPOMENTIAL FR 7B EHMP LIHEHR ZB 2HkHz RESET 16 OCT 94 63 03 25 m EE m o FILTER 14 25 8 Hz Les f 2 HORMAL OAS m INITIAL Press the EXIT hardkey the display sequence will begin immediately You may repeat the display sequence by press ing the DRAW 1 D key 16 007 A310733 os DRRU 1 DRRU 2 START END DELTA SPL B 14064 38 EXF HEHTIHL 148 bTIME Ea PREAMP LIHEHE 24A 2AkHz s i RESET 16 OCT 94 025025 25 p FILTER 14 25 6 Hz Les Channel 1 af 2 NORMAL WATERFALL PLOT TART 9991 Ho Bua E E S DELTA 996 1 3 G Hz SHE Hz 16 8kHz E A OFF INITIAL 2900B TRAINING
107. 5 In this case all of the sound intensity measurements for the job are used Press Power A to initiate the sound power Q i A summation note i BEE LINEAR SIHGLE B 1 LINEAR zBHz 1BkHz T 13 JAN 33 a 4 FILTER 24 208 Hz L 3 POWER 1 d 13 8mm 6d St des BABE E a 5tf A 73 2fTdBrFl 10570792 a Dyer 25 8 Hz Saa Hz 16 6kHz E A dotted crsr AITEST S gt JDE SPART SeARER S EDIT Cl F4 2 C24F4 2 F3 F2 16 On the display you will see the total sound power spectra of the job At the right of the display you can read the values of the total overall sound power Linear amp A Weighted of the job plus the sound power at each 1 3 octave band 13 ded GS 325 25 Power F2 P I F3 HPF F4 FHU nate Hote dE el 2B 9902 LINEAR SIMGLE zB 9962 Dual Beep eee IER i 258 Hz LA POWER 1 d 13 8m 64 9 des able A 9 o9td Bel 725 8 Hz SBB Hz B BkHz ER dotted crar AITEST S gt JOB SPART SAKEA S EDIT Cl F4 2 Cz F4 2 F3 F2 17 Press CURSOR and then the left or right arrow keys to move the cursor to view the sound power levels at the other 1 3 CURSOR EXIT octave bands Press EXIT 18 To generate sound power totals for an individual part of Mss yy Q the job press S gt JOB I A 13 JAN 0 00 51 Power F2 F I FS NPP F4 FNU note i Hote dE Ell 54 o AAA E O OS LIHEAR SIHGLE 2B AHHH i ua LINEAR ZBHz 1BkHz RESET 13 IHH 92 61 60 11 16 FILTER 24 2980 Hz L 3 PE over d 13 8 i d 19 44 des BEBE mE SH o PEA AA ae
108. 6 SPEED B d Edd B dotted crar IHITIHL 13 To check the calibration make sure the calibrator is still on RESET then press R S to run the RTA H S s eel 16 86 36 SLOPE name SAME k UHITS Hoise F ml cal U cal level 11 5600 Z Sr E 1Hz 1b6kHz a4 16668 2S 1 581 E de l 2366Hz HBAR 1 HORMAL 64E 6 ral Loc TACH 6 6 SPEED B amp E t 06 Bn dotted crar IHITIHL dE Ll SPL G FT75 under under undef undef 14 The level at the cursor position should read about 1 0 8rms SHIFT This represents the reference level In other words on a loga rithmic scale this would be O dB Return to logarithmic dB scale by pressing SHIFT and then Y AXIS B 14 BEF 16 Geide R HKIS U SCHLE W OFSET H SCALE H OFSET FFTZO0M 7S 5664 2 orz EXPONENTIAL A InrFut 1 LINEAR 1Hz 1 kHz LIH 14 APR 94 15 86 23 1 581 FREQ 81 2566Hz HSAA Channel 1 of 1 HORMAL lt d 1 86E 68H E 1 64E 68 rol LOC TACH BH SPEED Aa E 4 ab i dotted crar IHITIHL MC STOP McWwAIT McREPT Batters SameREF SetREF ws REF 7 12 2900B TRAINING MANUAL RESET R S Averaging Once you have returned the display to a logarithmic vertical scale notice that the calibration level is indeed 0 dB 14 den 16 69 15 SLM STAND 1 STAND 2 CROSS IMTEHS s UNITS FILTER 7 SHR rra A EXPONEHT IAL a Ineut 1 LIMEBRE 1H 10kHz STOP 14 APR 94 16 82 54 rm qe E FER 21 2566Hz Hea 1 HORMAL TACH B B SPEED B a Bi p bel or ak
109. 6 19 16 TH Bo a ERE HHE R REER E cx TT FILTER 14 75 8 Hz Leo ie el 1 OE ce as T GA L DIFF Ph2 5PL Sn2 _ REM TACH B B SPEED 35 rom rm n LH A soe eok BEH dotted crsrIMITIAL 1 0 SIG GEN INPUT clock COLOR ML Press the EXIT hardkey to return to the System Menu 2 3 2900B TRAINING MANUAL Calibration based on a Reference Signal Before calibrating the analyzer verify that the exponential detec tor has been selected To calibrate the system based on a refer ence signal 1 Press the UNITS F key from the System menu F 2 Select either the SPL J key or one of the user defined keys K P to which the calibration level will be assigned PES 16 18 57 SLOPE name SAME E UHITS Hoise F ml cal U cal level SPL B aiam at Ip p l2 2 P TU phage Bn ERXF HEHT HL 178 Dua LIHEBHRE ZBHz zBkHz RESET ao ae 16 15 05 i d i 8 58 I AAA Ah AA e Aa ae ERT TR OR A RRR R DIFF Fh 52 8 Sn 7 45 i TACH B B SPEED 9 9 z5 H8 IHITIHL Me SEC dao under Under under under E E Under 3 Apply a known excitation level say from a microphone cali brator to the transducer in this case a microphone 4 Press the R S hardkey to run the analyzer RESET R S 5 Move the cursor to the frequency of excitation by using the left or right arrow keys Press the level H key xr 16 25 39 SLOPE name SAME R UNITS Hoise F ml cal L cal leve U SPL 22 4668 O ut botte m tbe H EXPONENT IAL 1 8
110. 688 SFL PA hehehe ee eee eee eee EXPOHEHTIBL 1 3 Ineut 1 LIHEAR 2B8Hz ZzBkHz OF 19 B 398 _ 17 83 ST FE a SEXIES NN eo dus ndis fay Tal CE May do Via RO oec lo way a aw SL uiii ia wol bv flee tev CE EE Tl ZEB MEE aly da vs dr da EURO FREQ Ae AARAHZ H4HH Channel 1 of 1 HORMAL d 47 3 B 65 4 TACH Ha SPEED a d E datted crar 166line 290 1 1ne 468line S66line EET ZOOM X WINDOW JZBASE Bd BB IMITIAL 3 Press one of the following keys to select the time weighting window 13 FEB 17 65 39 RECT HAHHIHG FLAT ZEROPAD IMPACT EXP 2 ERF 4 EXP SPL E BEBA TE KKR R LR A RA EXPOHENTIAL 1 48 Ingut 1 LINEAR 26Hz 2BkHz FESET 19 FEB 938 17 84 13 pa Wt WR dw lec R M RC CADO a an OUO cay DD CM 2c Gowda aan WO a R R R N NT ee R eee cca O Gee D del Geb ewe ON FREQ Aa BHARAHz HSHH r Channel 1 of 1 NORMAL d 33 E 6 6 e BE TACH 9 09 SPEED B A QG a zUUM T Ipan 009p E A dotted crar IHITIHL For Rectangular Weighting on all channels Provides the finest frequency resolution but is often accompanied by excessive leak age of energy to the neighboring sidebands For Hanning Weighting on all channels Used with steady sig nals gives better frequency resolution For Flat Top Weighting on all channels Used with steady signals gives better amplitude accuracy in the passband For Zero Pad with without Bow Tie Correction on all channels For Impact Weighting on channel 1 Rectangular Weighti
111. 6h eu FILTER Er 5 Ell Hz Leo Channel 1 of 1 usTIME d 52 1 A 65 8 46 o ee A PHOHS aa TACH 8 46 SPEED B amp E Hz Q k Hz brec all data EDS usEFHM STHT Mx Spec F TEIG SETUP FILES AUTOSTR 7 Next press RT60 D aS OCT 17 52 57 WC HR RC Ftse src R u Ii Hote SPL WERAGED BH CDI CIE Er TX LIHEHE FEPEAT ALA TIneut 1 LINEAR Z2BHz 24kHz RESET 458 OCT 94 15 82 54 5h Bd do m0 9 E Sen Be a el eee cds ea Bed ee a 80 18 Ta dee E FILTER LET E Ell Hz Leo Channel 1 of 1 usTIME d 52 1 A 65 8 46 o A A PHOHS E D TACH BH SPEED B amp Q kk H dotted crsr S z EDS surface valume You should be viewing the RT60 register that you previously filled ZH FEB 15 84 32 R RT B Huto KE Auto Al nate ETEB Hote i SPL WERAGED 18 2r sc 2 c 50 sci b o A O oo LINEAR FEFEAT HLA bT IME Dual LINEAR 28Hz 1BkHz RESET 26 FEB 398 13 17 55 1z ir ne o llle rennen E 75 48 ES 5 Ell Hz ERE r FRT 64 DATA r RT66 4 226 HHla Hi HE o MEMINI G A Ba DG FEM DIG o A EE al deri as a Jae TRA a H Hz EH Hz d HBEHz A dotted cram ROOMS lthresh thresh Auto TH SOLID COTTED edit 8 Press the SYSTEM hardkey to get back to the system menu Next measure the sound pressure levels in 1 3 octave bands of the source and receiving rooms You can do this one of 2 ways You can measure them one at a time using the analyzer in the SIANDRD single channel mode or measure them simulta neously using STAN
112. 81line 9991 ine FTZOOM LU T NDO BASEL Ed Satisfies the ANSI 51 11 1986 requirements for Type 1 D classifi cation This is used for measurements which require a particular ly fast filter time response such as gunshots The slope of the short filter skirts is less than that of the long filter however the resolution of the short filter is not as fine as that of the long filter EE 16 38 16 1rloct loc L lona reverse 13 6688 114 RE A a dI cr MG A et ao 8 06 oor a O Gye hae ha KO s ERXF HEHT HL 1 4 E Dual LIHEHR 26Hz 2HkHz STOP 19 FEB 98 16 37 49 I6 r EREEREER AREE 2 0 PEEN ENEE EE EEEE oe at EE EE Ze FILTER 14 75 4 Hz Sri Channel 1 of Z HORMAL d 31 6 H wl rer v aa R K See ey a a ae a a ye RR RR we DIFF Ph 142 B n Ts He REM TACH 8 8 SPEED B B SH UN Oa XM P58 A ag cae we vay Sey ay Mey Teh Ge CAL vay AL ee ee A C HZ ae i3 IHITIHL 1641line 2801 ine 4481 ine sa l ine FFTZOOM lU L NDO BASEL Ed 2900B TRAINING MANUAL reverse H The reverse time short filter is used for measuring short RT It re duces residual time of the filter by a factor of 10 It allows mea surements of RT at 200 Hz down to about 20 ms MEE 16 38 16 1lrloct le Zoct lona short reverso SPL 13 6688 1 15 E Ex EXF HEHT T DL 1 Dual LIHEHRE 2H8Hz zBkHz STOP 19 FEB 938 1613195 38 a A o E E O e E A E Mom ame a FILTER 14 25 IS Hz Er E y Channel 1 p z POR ARE 79 HIHIH a DIFF Ph 142 E n TS HE RS TAC
113. 9 SB LI i Dual LIHE RESET 12 JAN 98 23 58 14 18 FILTER 24 258 Hz L 3 il wr INTENSITY i de 13 0mm 54 Wo Cw ay r Gk Qc GE Sl WO cl Gee Ow ke E i PP F lJ z 1 4tdB gal BAEZ JOB TEST REM PART FRONT rn AE A A A EM a dz FOIHTI1 iu EB Hz SHE Hz 164 BkHz Z A dotted crear AITEST 8 Press EXIT to return to the MAIN menu Performing a measurement Now to make a measurement point the front of the intensity probe towards the noise source 1 Press KEY A on the probe or the R S hard key to initiate the RESET measurement Either scan the probe about the measure R S ment surface in an orthogonal fashion or fix the probe at a single point orthogonal to the surface until the end of the averaging time is reached The first measurement is now complete 13 dal mE gd2 1z POWER IMTHST QUALITY SPL P WELOC DISPLAY note DETECTA I dr m 26 Eng n L E a ps wirt SIHGLE zB 2690 Dual LIHEHE 26Hz 16kHz OF 13 JAH 93 GQ us FILTER 24 z956 Hz Lx e INTENSITY 1 d 13 8mm d 58 6t YS 54 RO E A A TN E AAA E F lJz ns amp tdE al amp i tmme l JOB TEST FEM i FART FRONT ab ive Dh ep oh Cf Gat ut n RT ORC DC c Te HERB MIEL LLL ct A ee Ra cn O AREA POIWT1 25 Q Hz SHE Hz 16 8kHz A dotted crsr AITEST Job Fart area Pree tL se meter SETUP FILES AUTOSTR The 1 3 octave bands above the center line of the display denote positive acoustic intensity Bands below the center line indicate negative intensity
114. 900B TRAINING MANUAL RESET 13 14 R S 1 Press R S to initiate the measurement Notice that the FFT from the accelerometer is being displayed on the 2900 screen Also notice that the trigger is ARMED and waiting Note the current RPM reading from the tachometer is displayed on the lower right side of the display 15 OCT 22121145 OFF ESTIME delta endztar Am 6 a 6 2368 EXPOHEHTIAL 1 64 Inrut 1 LINEAR 1Hz 1 kHz RUH 15 OCT 94 22 21 38 A AG B6BBAHz H4AA Channel 1 of 1 HORMAL d 68 6 E 26 7 TACH 282 9 SPEED 4 4 db H dotted crar DCMHOTO ba4THCH TACHSET F TRIG FILES Next you will increase the speed of the DCmotor until the autostored is triggered at 500 RPM Notice that TRIGGERED appears at the top corner of the display indicated that the byTACH autostore has begun 16 OCT 13 56 18 OFF byTIME delta endstor Tote BE BY TACH TRIGGERED G B 3200 EXPOHEHTIAL 1 64 Inrut 1 LINERE 1Hz 1 kHz RUH 16 OCT 94 13 56 19 i AG BRBBHz H4AA Channel 1 of 1 HORMAL d 45 3 E 25 4 TACH 366 5 JSPEED 48 4 tdotted crsr ILES P S bsTACH TACHSET F TRIG As you continue to increase the speed of the DC motor spec tra will be stored in approximate 20 RPM increments until the speed reaches 3000 RPM At that point the autostore is complete and the data will be automatically stored Below is the final spectra acquired at 3000 RPM 16 S 14 37 35 W Fall E AWE E HAs
115. AL DIFF Ph 98 8 Sn 32 16 FEM TACH H 4 SPEED B d H Hz Eo Hz recall data ROOMS DELETE A Frer H Hext In order to view the actual values of the RT60 for the decay curve both the solid and dotted cursors are used 3 First press SOLID N to activate the solid line cursor ZD or 19 32 83 ET amp B REPLACE AVERAGE Huto RE Auto AL note N Hate SPL EFHGED Eu FEFEHT B 6564 al LIHEHE 26Hz 16kHz RESET z FEB 98 15 17 55 DATA 32 1 66kHz 5 3 Channel 1 of 2 uzTIME Ls 56 8 Ts p 6560 ET6B 0 HHA ct B doti Lo Ue RutoTH Max 5 4 S H REM ok px 55 5 ER a 16 S B assa 2 BEBE olid crs ROOMS lthresh hthresh A Prev B Hext DHTH SOLID DOTTED BOTH 4 Next press the right or left arrow hardkey until the solid cursor is somewhere along the leading edge of the linear portion of the decay curve ZH SEE 15132143 ETEB FEFLHCE AVERAGE Auto RE Auto HU note Hate SPL WERAGED KE FEPEAT B a La LIHEBHRE ZBHz l8kHz RESET 2 xd 38 15 17 95 i TH 1 66kHz 5 3 i Channel 1 of Z usTIME lt i Lz 57 9 Ts 1 8568 3B P NE RR M er P eme i REN ERES TI NESERMS RTEA 65 235 ct B 5544 i AA HutaoTH Hax 25 0 S l REM 1 A E A IRE Ley E 45 Se lt 5 B dam zm solid crzr ROOMS lthresh hthresh A Preu H Hext DATA SOLID DOTTED BOTH 9 16 5 2900B TRAINING MANUAL Then press DOTTED O to activate the dotted line cursor zH DEP 19 32 43 RT amp B REPLACE AVERAGE Auto RE Auto HU no
116. AR 26Hz 26kHz RESET 07 JON 98 BirddrBr 7a A RR RR A RR ae select mo R ca FREQ He HRORRHS HSARA Auto Sreectrum d 15 3 B 12 6 B R XR rE XR RN a E KR RR RR KN NR LRR R RR N RR NN N NR RR K R Base Fresuenc y Ae HHHH EH TACH H B SPEED HL aa EH dotted crar IHITIHL If you wish to expand the frequency scale further first move the dotted cursor to the extreme left side of the display To do this press CURSOR then press the left arrow key until the dotted cursor is at the left side of the display as far as it can move 6 Next press SHIFT and the H SCALE E E Ed 13 43 85 AXIS YARIS U SCHLE U FSEY H SCHLB H OFSET FFTZ00M SPL B BEBE ET TRE EXF HEHT T DL 1 E ua LIMEHR 258Hz zB kHz RESET 12 OCT 34 13 42 63 FEEL Bs 7a CQ PLE Tcp O E ATR RL RRR Cad Ca at HRREHS HSARA Auto SrEectrum d 15 3 a z H ab AR E ETE 2 s A is NN Sif Sa R X R Base Frae uencuaz Ae S LOC TACH BH SPEED B B G8 GREE Z nM 1 2500 6000 Z A dotted crsr IHITIHL Nc STOP McWAIT McREPT Battery H RMSET HORMALZ SetREF WSREF 7 The 1 A 2 B 4 C and 8 D keys will expand the display by the associated numerical multiplier Press 2 B to expand the display by a factor of 2 B JAN 615 de 29 1 C 2 4 S G A SELECT Horizontal Scale 11 18 EXIT E SPL B HHHH 2 PERTERRITI O K Ses o RR RR K eve es A Ge ced E EC bl 1 B8 al LINEAR 26Hz 26k Hz RESET Br JAN 98 61145125 TE KX R RR O AA EO ke ee K
117. ART E to enter these values c 15 OCT 22 959 2Z DRAW 1 DEHW 2 START EHD DELTA 4 5668 IBL E LIHEAF iHz 1BkHz 3 OCT 94 22 21 38 HE maaaHz H4AA 1 i of 1 HORMAL L PLOT Eam E115 BEE 13 15 2900B TRAINING MANUAL EXIT EXIT vsRPM Graphics 13 16 3 These number should be entered as W FALL s0001 e0113 d0003 15 OCT 22935255 SIS TTT FALL 20001 62000 0004 o EXPONENT LAL bTACH I InrFut 1 L STOP 15 OCT 94 22 21 38 SEC Bn Care Tes A Ea ute NAAA NA al Poe Der E de E A RN D AE e a n o eL e FREQ AA HnammmHz H4HH i Channel of 1 HORMAL WATERF LL LOT n IS I I I2 an DCMOT O Press EXIT to enter the waterfall display values and initiate the plot Below is the DRAW 1 waterfall display Notice that it plots the individual spectra on top of one another Notice how the fre quencies have shifted as the speed increased 6 15 al 22 97 19 DRAW 1 DRAW 2 START END CELTA 4 25604 2H NR E a CES ae es Wee a eR je EXPONENTIAL 1 64 bTHCH Inrut 1 LIHEHEF iHz 1HBkHz STOP 15 OCT 94 225215 HENRI 1 A ee rBmRREnRERHn UR FEEG nid ARARAH H4HH Channel 1 of 1 HORMAL WATERFALL PLOT ger a NM START Gaal EHD 8113 COE i CELTA 062 2 He BEBA OFF OCMOTOR To view the waterfall map in a skewed quasi 3D format choose DRAW 2 D EHD DELTA wate Gi 4 5600 SEEN EXPONENTIAL z M Input 1 LINEAR 1Hz 18kHz B STOP aq 22 21 38 15 cT E
118. B A288 1Hz 18kHz d 1514213 FREQUENCY 7 MATA GO ZT am AIA raD a cl K rl m rau e ASAS AIN A A cD Den Cau n T ed Kk Kek Kek Kd Kk 3 LD SAP Cy Io n 3006 DCMOTOR STATUS HIDE TACHSET B ORDER REDRAW PEH 2900B TRAINING MANUAL 7 Next press the right arrow key until the PEN 06 frequency has changed to 200 Hz 16 EL 15 44 21 SLOPE elevel TAGERES As S5FHH VIDEO BOARS note WIDTH G 4 8268 EXPOMENTIAL Bed Ineut 1 LINEAR 1Hz 1 kHz FESET 16 OCT 94 15 42 36 FEH LEVEL C FREQUENCY i 56 7 1 12 504 z Hz 59 6 1 25 lb 3 BHi 49 5 1 Sr Jee 4 H4 258 8 1 SB El B5 27 3 1 62 26 BE 225 7 1 264 000 gi 666 FM T06 freauencu DCHOTOR STATUS HIDE TACHSET B ORDEF FEDFAL FEH CHRHHHEL FEEL 8 Press REDRAW M 16 aT 15 44 21 SLOPE eleyvel TAGBARS H SPAN WIDEO RAR IS note WIDTH M G 4 8268 EXPOMENTIAL eS i 1 LIHEBR 1Hz 146kHz FESE 16 OCT 94 15 42 36 FEH LEVEL C FREQUENCY 1 Bl 56 7 1 12 504 z Hz 59 6 1 25 468 X BHi 49 5 1 Sr Jee 4 H4 258 8 1 5B Ell B 5 27 3 1 62 26 md BHE 2325 7 1 zBB 000 gi ALE ENH 56 freauencu DCHOTOR STATUS HICE THCHSET B ORDER X REGRANN FEH CHAMHEL FEEL The 6 frequency traces will be redrawn on the display PEN 06 now contains the 200 Hz frequency band PENS 01 through 06 can be modified in this fashion to display any fre quencies that you wish 16 el 15 45 H SLOPE amp 4level TAGERES SPAN VIDEO A81S
119. B glnBlnMne BIFF Ph 141 Sn ri 96 REM TACH 8 0 SPEED 4 4 qu z z dotted crer IMITIAL T LIHK 300 ED 1200 Z Gabo 45460 2606 19200 7 Press KEY B E to program KEY B on the probe to remotely U store data E 12 18 2900B TRAINING MANUAL 8 amp STORE 9 EXIT 2 3168 146 A ANNA aS Se EXPOHENTIAL e Dua LIMEHR 26Hz 16kHz STO 12 JAH 33 2H145 0 Bh RC anaes E ay ole E CARA ats Tat E As Sid O A FILTER 24 75 Leo Channel 1 of Z HORMAL d 114 5 A m BH E PR oe we ea ox X oon o X X Xx o X XX E BIFF Ph 141 6 n 72 He iim TACH 9 9 SPEED B d z z 3 z datted crar IHITIHL T LIHK 60 GDG 1266 zd 4368 9668 192668 Then press followed by the STORE hard key Pressing KEY B on the probe will now store the current displayed measurement to the active data file in the 2900B memory 12 Bh 21 66 34 S268RC DC out 10 Port KEY A KEY B Beerer ES1 IHT 2 5168 SPL 190 TTT EXPO I L 148 Dual LINEAR 26Hz 16kHz STOP 12 JAN 98 28 48 81 oh Y AT K cme N 09 SSE a A 171 R R DEMO FILTER 24 254 Hz Les Channel 1 af 2 HORMAL d 114 8 AH E E e a ale sat RAM N 55 e e E lay a o A E R NNN E GI F hz PEM ig TACH 8 8 SPEED B d datted crar z d 7468 4508 9688 19756 Z x IHITIRL T LIHE 368 ea 1206 Press EXIT twice to return to the SYSTEM menu Creating a measurement data file Next we need to create a measurement data file This is the file where our Acoustic Intensity measurements will
120. CH 8 0 SPEED 4 4 Bess ee ee a OS ee DMG eS Sd SRO REE Ee a os p I 24 4 Hz 636 Hz zH BkHz dotted crar INITIAL I J K L H H P Enter the new desired Unit name M SEC by using the alpha characters appearing on the display Typical names for Units are g m sec ft sec or psi de eg ane MEN Pensa ae E E 2 3 an r TD A AA A A a R N KR EXPOHEHT IAL ie Midas Dual LINEAR zBHz zBkHz RESET 19 FEB 923 16 13 19 TH I C P aad ML 1 sl iC FILTER 14 75 4 Hz Leo Channel 1 of 2 HORMAL d H 34 9 SH ee DE E ER ERL AL REER ARE E O E DIFF Fh S78 n 7 45 REM TACH 8 0 SPEED 4 6 SED a dt RA de dob dod A i ah AA l g 25 5 Hz 636 Hz 2H Bk HZ dotted crar IHITIRL I J K L H H P Press the EXIT hardkey The new name M SEC will appear on the softkey previously selected lo deniers SLOPE name o SAME R UHITS Hoise F ml cal U cal level SPL B ABE aj Wu LK LE C E E EXF HEHT T DL 1 9 Dual LINEAR ZBHz ZBkHz RESET 19 FEB 923 16 18 05 79 IIT FILTER 14 25 Q Hz Leo Channel 1 of 2 HORMAL d 23 8 H x SH I LI LLLI LL A ac BIFF Fhz be 5 n 7 45 ee Se O O O O O O O O TRCH B d SPEED B d ps B BkHz dotted cran INITIAL dE el undef undef undef undef undef Press the newly named unit key M SEC The new name will appear on the upper right side of the display 9 16 20 20 SChanls SLI HH STRHDRD CROSS IHTENS UNITS FILTER CLASS mesec G 0988 ECE Beet NT T BL 1 3 Dual LINEAR _26Hz 2Bk Hz RESET 19 FEB 9223 1
121. D to set the status of the band indi cated by the active cursor In this manner noise can be generated for any combination of 1 3 octave bands con tiguous or not When using the analyzer to measure the spectrum of the noise generated the user should bear in mind the effect of filter selectivity due to filter skirts not being perfectly ver tical on the measured spectrum For example with noise generated in a single band the measurement will produce a spectrum indicating noise in the two adjacent sidebands at levels approximately 17 dB lower This phenomenon is associated with the measurement process only and does not represent the much more accurate bandlimited noise actually being produced To return to the Wideband Pink Noise Menu press WIDE A then press Exit to signal generator window 2900B TRAINING MANUAL White K K 2 22 The Wideband White Noise Menu shown below is accessed from the Signal Generator Menu by pressing WHITE K or TER 16 66 56 PSEUDO LEWEL lt ATT 2HTT l SPL 278 8700 o EXPOHENTIAL 148 Dual LIHEBRE zBHz z kHz STOP 26 FEB 98 18 65 ca A LITE AA E E NA FILTER 14 2B B Hz Les Channel 1 af 2 HORMAL 66 A 99 5 A a a cea pak Be a E E O c BIFF Fhz11z H 5n 147 98 FEM TACH 6 64 SPEED B d doatted crar INITIAL White noise has equal energy per constant bandwidth e g narrowband FFT analysis To view the change go back to the System menu press FILTER and choose 800 line
122. D DOTTED BOTH 15 If necessary move the solid and dotted cursors such that they are both on the linear part of the decay curve Remember to activate the cursor first by pressing either SOLID N or DOT TED O ZH EEE 15 58 53 RT 6 REPLACE AVERAGE Auto RE Auto Al note Hote SF EFHGED pru FEFEHT Ha B d La L R 26Hz 16kHz RESET 2B FEB 38 15 17 55 16 Notice that the RT60 for the 2 0 kHz band is 0 218 seconds S Press REPLACE C to put this value into the RT60 register C zh dz 15 58 53 ETEB CREFLACE average Auto RE Auto HU note Hote SPL WERAGED LINEAR FEPEAT B d Dual LIHEHE 26Hz 16kHz FESET 26 FEB 93 155175 DATA 233 Channel 1 of 2 a G ETEH 42153 ct ETT S ST 25 8 5 8 ox x x o px FEM ar DP REED Gate T REL Tali i Sr r 56 0 B dam zZ HERE new data ROOMS lthresh hthresh A Preu H Hext DATA SOLID DOTTED BOTH 17 Continue this process moving the cursors to the linear areas of the decay curves and pressing REPLACE C for each of the frequencies until you get to the 5 kHz band Once you have finished press RT60 B zH FEB 15 58 93 REPLHCE AVERAGE Auto RE Auto Al note RUERBGED ama EAT HEBR _26Hz 16k Hz FEB 98 15 17 55 2 09992 new data ROOMS lthresh hthresh A Prey A Hext DATA SOLID DOTTED BOTH 9 20 2900B TRAINING MANUAL 18 Below is the completed RT60 register For this example you are only concerned with the frequencies from 400 Hz to 5
123. DISPLAY note Crec G r 2588 w EXSPONENTIAL 1 3 Ineut 1 LIMEBRE 1H 10kHz STOP 21 MAR 94 09 46 24 FREQ s1 2 lt 5b66Hz HAA Channel i of 1 HORMAL lt d Go f 6 2 TACH B B SPEED B a dotted crar SETUF FILES HUT STFE gt N ro un un E p Z un E er O 5 5 2 D zi 5 En 3 pas D 5 lt O 5 pe 5 ga G 7 2900 EXPOHNEHTIAL 1 5 Ineut 1 LIHEBR 1Hz l1B8kHz STOP 21 MBR 94 mo 45 24 2566Hz HSAA zl Ds oie are LIH R EXP EPU N COUNT 5 COUNT E Al TIME Rej Channel 1 of 1 HOBMAL d 48 6 a BZ e gis THCH HBH 8 SPEED 4 6 Bel k dotted crzr UIEi 3 Next choose AV TIME H to select the measurement averag X ing time H 21 Es deep LIH 5 LIH FR ESF EXPO H COUHT S COUHT R G LIHEHE 5IHGLE B 725 Ineut 1 LIHEHEF 1Hz 14kHz RESET 21 MAR 94 18 17 13 FREQ 51 2566Hz HAA Channel 1 of 1 HORMAL g 123 1 E 95 TACH 6 8 SPEED 4 4 dotted crsr 4 For this example select a 20 second averaging time detector EXIT time by typing 000020 0000 using the alpha keys on the RTA keyboard Then press EXIT to enter the number zl MAR 16 15 36 Bal DETECTOR TIMEN B Bp LIHEHR SIHGLE B 2566 Ineut 1 LIHEBR 1Hz 1B8kHz RESET 21 MAR 94 18 17 19 FREQ 51 2566Hz E uH Channel 1 of 1 HORM d 123 1 z 85 8 TACH 6 8 SPEED 4 4 dotted crsr 7 14 2900B TRAINING MANUAL RESET R S Zoom Processing SCREEN SYSTEM Notice
124. DRD dual channel mode of the 2900B For simplicity lets measure one channel at a time 9 23 2900B TRAINING MANUAL 9 24 9 Put the analyzer in single channel mode by using the STAN DRD i a and Chanls A key L EB BEBA aj O A RA EXPOHENTIAL 148 ual LIHEBRE zBHz z kHz SET 19 FEB 38 16 65 48 TA E E FILTER 14 25 B Hz Les Channel 1 of 2 HORMAL d 3735 4 A 34 49 54 r DA RA de de A AA A A A ae e din 9o we Se AAA DIFF Fhz nz a 5n T 45 a TACH 4 8 SPEED B B z5 H8 Hz 6360 Hz zH BHEHz datted crar INITIAL I O SIG GEN INPUT clock COLOF MLS FILES RESETS 10 Set the averaging type and time by first pressing the EXIT hardkey and then select DETECTR H 23 FEB 18 63 44 NORMAL Lea HIH HARS SEL DISPLAY note DETECTE GBB 10 03 44 NORMAL Les MIN MAR SEL SPL A etm 168 iets ta SE ae RS dee A AR A dR ae sh A ERR KT a A R EXPOHENTIAL 1 E Dual LINEAR ZzBHz zBa kHz RESET z3 FEB 98 95562 d SH E O A NR RR FILTER 14 zh Q Hz Leo VE Channel 1 v Z AE 6B P BIFF Phz 65 9 Sn 6 85 REM l TACH 9 09 SPEED AA 25 8 Hz Bae Hz TE oe L datted crar ROOMS ROOMS us EPI STAT Mx Spec F a TEIG SETUP FILES AUTOSTR 11 For this part of the test you will use linear single averaging Choose LIN S A mE 14 64 15 uu LIH F EXP BT ESP ET LIH Al TIME 1 SPL EB Bab 146 r A E E aa a R T dal R dau he EXF HEHT T DL 1 78 Dual LIHEHE z26Hz z kHz R SET Z3 FEB 98 BH9 56 54 Sn a A H vee CU LC OCT A 6 R San
125. E CUR R er naa 0 R FEE Bi HnammmHz H4HH Channel 1 of 1 HORMAL d 15 3 a 3 6 zi JI xxt M M l I Ld ova Ae dotted crzr IHITIRL As mentioned you will measure our FFT spectra out to 5 kHz frequency Let s establish this baseband by pressing BASE Bd C Ei S c ace o m oe SENSE SPL B HHHH GE A EXPOHWEWT IAL 1 A Ineut 1 LINEAR 2B8Hz 2BkHz RESET 15 OCT 94 17 83 18 ae AE US OR A E ves ELE e 8 AA O cu GE EISE E SAU A R N FREQ An HnammmHz H4HH Channel 1 of 1 NORMAL d 15 3 a 2 0 ze Se LOC THCH 6 6 SPEED 4 6 2 EMT 13 3 2900B TRAINING MANUAL 9 Select 5kHz C as the upper band edge frequency 16 OCT 11 32 29 ZBkH 18kH SC H Z 2KH SPL B BEBE SL Ae ok AAA A GE GR ecd Del E RE A SucRICELAR ARS UR URS XE SE R UE A Ode i ELTE URL TE EXF HEHT T DL 18 Inrut 1 LINEAR ZBHHz ZbBkHz RESET 16 OCT 94 11 29 53 4 a dal E T N N scar Ya La Vel el qe ae a ow Jw dr A a A a en ae e dm FREQ Ae BRARAH H4HH Channel 1 of 1 HORMAL d 15 3 2 Z ME Loc Foros mom ops 3 9 9 9o 3 9 9 9 o 9 9 n 9o 3 3 9 n l l TACH 8 8 PEED 8 8 Ge dotted crzr DCMOTOR 10 Notice that the frequency scale has changed to reflect this EXIT baseband selection Press EXIT to get back to the System menu 15 QT 19 26 31 loct A sss lona short E SPL B aaa eh ID IC Tr T EXF HEHT T DL 1 5 Inrut 1 LINEAR ZzBHHz ZbBkHz RESET 15 OCT 94 19 23 61 4 eer toe ae be sete sae
126. E FEFEAT BH ASHK bTIME Dual LIHEHR 26Hz 14kHz RESET 26 FEB 98 13 31 27 ae r EEEa RRR WBN Argon ETATE CECI FILTER 14 zh Q Hz Er 3 Channel 1 of 2 HORMAL d E 3 H SH A R RRR R R RN NN RR R R R RN RR R DIFF P Te 1 n d l I TACH H a SPEED B a x E datted crar ROOMS SIHE FIHK WHITE FULSE DELAY Since you want the pink noise generator to automatically shut off after 1 second into the Autostore you will use the delay feature of the noise generator 2900B TRAINING MANUAL EXIT 3 Press DELAY O a S 13 42 25 OH OFF OM RUM 0FE RUH lt ATT ATT SPL 99929 TH r KE REE A O RT R ME ARE IM MEE CHRIS REA R ER TEE ARA La a Cua RRR O EZ SEG 5 LIHEHFE FEFEHT BH Em bTIME Dual LINEAR 26Hz 16kHz RESET 26 FEB 98 13 31 27 SH r E ea E A RA RN A AN A KN a FILTER 14 75 8 Hz Sri Channel 1 of Z HORMAL d B 23 4 AB r KE dt wide R aE RR RVR RR RR E e Rd GRA Ns Tay ele A RE IT R a Ey de a ints e ART TA DIFF Fh Za 1 n dd REM TACH 9 89 SPEED B d z x mated crsr ROOMS SIHE FIHE WHITE PULSE Use the left and right arrow hard keys to establish the 1 0 second delay ZH S 13 45 68 DN OFF OH RUM UKE EUM amp HTT HTT SPL BAHA TH r A ait ees R RRR 9 O A A A A A A fa me Walesa 79 LIHEHFE FEFEAT D She bT IE Dual LIMEHR 26Hz 16kHz RESET 246 FEB 98 13 31 27 SH r RR RT A AN O E E A E SAES FILTER 14 75 4 Hz Sr Channel 1 of 2 HORMAL d s B 23 4 Ab r AA e A do ES X
127. E HAME CATE TIME SIZE MEMORY rename men delete rename The following message Delete highlighted file will appear on the right side of the display mina Com Hemor Free 193074 Disk Free MEMORY DATE TIME 1 22 EXIT 2900B TRAINING MANUAL Press either the YES A or NO C to answer the message Pressing YES will delete the file pressing NO will return you to the files menu without affecting the file Press the EXIT key to leave the FILES menu Recalling a previously stored record 1 Press the FILES O key found in either the Main Menu or the System Menu Select the FILE where the desired stored data record to be recalled can be found by using the C or 4 K arrow keys Press the RECORDS B key HS OCT 16 18 24 create FECORDS t disk t Format Memor Used ZEE Disk Used 761856 Hemor Free 223472 Disk Free 695296 YEL S ISK DATE HAME CATE TIME SIZE mr E m CA LOC DISK 7 delete rename mem delete rename A listing of the stored data records will appear on the right side of the display The record listing will show the TYPE of record stored i e Normal Intensity by Time SLM etc and a note if any that was attached when the data was stored AS OCT 16 86 24 create t T nate EEEF Hemor Used 2565624 Disk Used Hemor Free 22472 Disk Free FTF RECORDS qu MEMORY TIME DATE SIZE TYPE ig INITIAL nmn 2 34 i amp 6 51
128. E Hanes ead uot Ro BA gt Auto Store in rrosress SPL B S488 B AX Gis WAST oa T wie iA adh PTT E EE E CET MERECE EEIESE EXPOHWEWT IAL 1 A i Dual LIHEBR 2B8Hz 2zBkHz Gd OCT 94 75 525 ee E su Hai A ICM FILTER 1 BB Hz Lez Channel 1 of 2 HORMGL i d 3 S A 42 48 za PA o E PHONES 61 2 TACH 9 89 SPEED ALG 26 Hz Shek Hz Hz dotted crar INITIAL ROOMS uzREPHM STHT Mx S ac F TEIG SETUP FILES AUTOSTR s When the analyzer has reached the endstore time that was previously entered the message STORE By Time X will appear indicating the data has been stored to the memory of the analyzer The X indicates the record number of this type that has been stored in the pre selected file Any subse quent presses of the R S key will re initialize the Autostore function ad OCT 879559235 NORMAL Lex MIH mA DI SEL D aate DETECTE a iat sa Were c Brae cine A A TIE SM ae NR amt STORE Bu Time 3 SPL 16 688 ro E a a mR te sae See ed a ies a ena kv see CS ee M EXPOHWEWT IAL 1 ETIME Dual LINEAR zHHz zBHkHz i STOF 64 OCT 94 87 53 23 54 O A E A a ae ee E E eS FILTER 4 1 ME Hz Le 3 Channel 1 of 2 HORMAL lt i d A Zar KMS o AA o a o PHONS n3 5 LOC TACH H H SPEED B a 14 La aai S 24 Hz 2H H Hz Hl kHz dotted crar INITIAL ROOMS uzREPM STHT Mx S5rec F TREIG SETUP FILES AUTOSTR Recalling an Autostore To recall an Autostore measurement you must have the Autostore fe
129. E SPECT amp s FEF COHER TIME DISPLAY note DETECTE Hn LEF COUNT MANUAL ACCEPT Dual LIMEHR 1Hz 16kHz STOP HY JAN 93 22164135 FREE a 1256Hz ESHA Transfer Function Hi D 2 d 165 56 Base Fresuency AA em 162T td zH Chz Ha 27 TACH Ha SPEED a d He HHHH DOM 1 1246 8750 E H ofset DG IHITIHL ALTERN BuHORM FEE T TEIG SETUP FILES AUTOSTR 44 Press P lt gt R K to switch from rectangular coordinates to polar coordinates of the transfer function ui deus 22 14 25 H S5PECT C SPECT x FEFE COHERE TIME DISPLAY note DETECTR FEAL BG LEF COUNT MANUAL ACCEPT Dual LIHEHR 1Hz 14kHz STOP BY JAN 98 22 84 38 E kaa PREG B3 1258Hz ESHH Transfer Function H1 D 2 d 5 656 E Hi Base Frea uencu AA HHHH 58 10 td 28 CSS BB REM TREUZ 8 8 SPEEDS 8 4 Ab oppa Z00M 1 1246 8750 Z A U ofset BB INITIAL ALTERN BlNORM peor T TRIG SETUP FILES AUTOSTR 45 You are viewing the real portion of the transfer function To view the imaginary part press ALTERN I Br deu 22114154 H SPECT C SPECT amp FEFE COHER TIME DISPLAY note DETECTE Hn LEF B COUNT MANUAL ACCEPT Dual LIMEHR 1Hz 16kHz STOP HY JAN 93 22164135 FREQ B3 1256Hz ESAA Transfer Function H1 D 2 d 1 881 E IMAGINARY Base Freauencu A em 1647 td zB Che Ba ee TACH 6 8 SPEED B a G ABBA n M 1 1z46 2r58 E H ofset Be IMITIAL ALTER BuWIMORM Pe ok T TEIG SETU
130. E TIME SIZE MEMORY 7 delete rename mem delete rename Press EXIT again to get back to the System menu The filename ROOMS now appears in the lower left corner of the display indicating that it is the active measurement file From this point on all measurement records that are stored will reside in the ROOMS file oo 12 36 55 Chanls SLM A STANDRD CROSS INTENS Y UNITS FILTER CLASS SPL B etm 145 r A A E R TEST EXF HEHT T DL 1 78 Dual LINEAR ZBHz zBkHz RESET Z9 FEB 995 12 36 21 asi r X9 Aun idm a A E E E fe E E obs RACE GANE aae a E abt T UR fen A FILTER 14 75 8 Hz Leo ELE ede 1 Ec De aE r o DIFF Ph 65 9 n2 6 85 REM git TACH A SPEED Ae H Hz Bod Hz D EE HZ dotted_cre sr ROOM S I O 5SIG GEN INPUT clock COLOR MLS FILES RESETS 2900B TRAINING MANUAL Setting up the Microphones and Noise Source Connect a microphone microphone preamplifier and appropri ate length of microphone cable to the channel one input of the RTA Place the microphone using a tripod at the desired loca tion for your first measurement There are many techniques that can be used to excite a room The more common methods include popping a balloon firing a starting pistol or driving an amplifier speaker with broadband random noise Balloons and starting pistols are inexpensive and portable but lack low frequency components also not very repeatable The best method is to use a random noise generator and an a
131. EAM ALTERH BUMORM Por SETUP FILES AUTOSTR 39 SS 18 84 45 H SPECT C SPECT FER COHER TIME DISPLAY note DETECTE Hote 2 EF I Ad Gale seu bi O0 dui E 203 3 ORCI a koh OREN E eog epos aca COUNT SINGLE 4 DIRECT LINEAR 1 3 2kHz RESET Hl 18 B bar 2411 F 125Hz E An Base rese as TACH 4 46 SPEED dot ted TRIG SETUP FILES AUT on ALTA HLTERH BWwHORM PRSE 31 99 DOS 025 19 A SPECT C SPECT x FEE COHER TIME DISPLAY note DETECTE Hote ik GS Ad COUHT SIHGLE 4 DIRECT LINEAR 1 3 2kHz RESET Hi JAN 96 66 24 11 FRE BB ABBBHzZ ESA Auto SrFectrum D z d 36 5 n Base Freasuencu 2900B TRAINING MANUAL Impact Hammers Frequency Range Impact Hammer Tips Soft rubber tip Plastic tip Steel tip The usable frequency range is determined by the tip and the mass of the hammer Soft tips such as rubber provide a long impulse and yields a lower frequency range centered at low frequencies Hard tips such as steel or hard plastic provide a short impulse and a short frequency range at higher frequencies Heavier hammers will lower the frequency but increases the amplitude of the force spectrum The useful frequencyrange of an impact hammer is from DC to where the spectrum rolls off 10 to 20 dB ii SR 11545 12 D KERCT C zPLCT FTR a TIME LILA nnb2 DK TRE TR aa FLIBGER TIP colar LUTHER T LI Gi 2t DE Eds ient TACH EPEED H B JL TI HDD toth creors ALTER
132. ED ALA noizse DG 9 ROOMS WHITE DELAY LEWEL 9 5 2900B TRAINING MANUAL 3 Turn the noise generator on by pressing ON A Q een TEE dee sie aed TE A e SPL 6 6000 146 x E pl O O en A llc E EXF HEHT T DL 1 79 Dual LINEAR ZBHz 1BkHz RESET ZM FEB 93 12 86 45 SH gE RR RR RR N RRR R RRR RRR RR RRR E R ATR R R RRR D ERRER FILTER 14 z5 IS Hz Leo ME Channel 1 VE Z c T 68 ETC CETTE as es ee ede eh aes Ge cases aa DIFF B 65 9 nz E 6 85 REM TACH 8 0 SPEED 4 4 OE ein acoso een ed bt dita en vised da l l soh E R UkHz dotted crer ROOMS SIHE PIHE WHITE PULSE DELAY The noise generator will deliver a pink noise signal to the speaker amplifier system 4 Press R S Adjust the channel one input gain of the RTA RESET such that the signal is optimized without creating an over R S load condition The best way to do this is to press the down arrow hard key until and overload occurs 28 BB 12 28 11 OH OFF O H RLUH OFF RLH amp HTT HTT SPL 3 1668 EXPOHENTIAL 1 3 Dual LIMEHR 26Hz 16kHz TOP zH FEB 98 12127126 H Hz 543 E Channel 1 oie Z HORMAL lt 8 DIFF Ph 89 1 Sn 38 28 FEM TACH 9 9 SPEED Bg d R Hz Bak Hz A kHz doatted crar ROOMS SIHE FIHK WHITE DELAY 5 Range up by pressing the up arrow hard key until the over load indicator disappears zH o0 12 29 11 OM OFF OH FUM OFF RUM ATT ATT gt gt SPL 4 7358 EXPOHENTIAL 1 8 Dual LIHMEHR 26Hz 16kHz STOP Za as 12125134 FILTER 14
133. EED B amp E E reca ata 11 dat IHITIHL DELETE H Freus H Hext recall Press the horizontal arrow keys to move through the autostored measurement Each spectrum displayed with each key press is a time slice that correlates to the autostore delta rate set at the time of the measurement The last spec trum displayed will be the last autostore performed when the End Time was reached Press the vsTIME C key to view the stored spectrum vs time 44 OCT 23 58 44 W Fall E AVE lus TIME KEEP LI P e e nnn RECALL By Time 1 i Hate TEST 1 i SPL HB 1888 O e e e e e n EXPOHEHTIAL 148 BTIME Dual LINEAR 2B8Hz ZBkHz STOP Bd OCT 94 maine 28 E eee X ILL 1 CE Lu FILTER H 1 15 Hz Leo i Channel 1 of 2 HORMAL d A 46 4 2B EM PTT T ULTIO TTL PHOHS T a I I l TACH 8 8 SPEED 4 4 z S s recall data IHITIHL DELETE H Freu H Hext recall EXIT 2900B TRAINING MANUAL 5 Press the DATA M key to assign the right and left arrow keys as frequency selectors which will permit you to scroll through the frequency bands 12 FEB 17 26 05 ETE REPLACE AVERAGE Auto FRE Auto Al note Hote UP T HD B 1668 EXPOMENTIAL 1 5 Dual LINEAR _26Hz 26k Hz RESET 12 FEB 98 16 45 DATA 32 Ld S RTGg 7 311 ct 2 ARBRE HutaTH Max 25 8 aH e Dk Ley 72 8 Pi 5B 3 B 1056 3 40 dotted crar DUUE UZ lthresh hthresh A Prev H Hext Chara SOLID DOTTED BOTH REM 6 Press the horizontal arrow keys to display
134. EED B amp wok H SH Hz D SC HZ dotted crsr IHITIHL DEFAULT HOISE Under under undet undef Under Under 2 Re assign any desired analyzer setups to the softkeys J P 3 Press the EXIT key to return from the Setup menu Data measured are stored to non volatile RAM into files that have been created by the user With the optional disk drive DVX003 these files can be subsequently transferred from inter nal memory to a floppy drive and also from a floppy disk back into the internal memory 2900B TRAINING MANUAL Creating a new file 1 Press the FILES O key to access the Files menu of the ana lyzer This key can be found from either the Main Menu or the System Menu 501 ea nate AS ST 15 58 31 WORMAL L MIH MAH SEL DISPLAY t DETECTE I i FL 14 5506 TH SR Remo wc Ro VR Um ORE Cds URS UNS gd Gee Ek a R RE RR Re VAT A a A Re a a Sa a 9 EXPONENTIAL 1 75 Lal LINEAR 2AHz 26k Hz i STOP 63 OCT 94 15 35 14 54 H ee EE a a a a a a we E xx FILTER 4 1 E oh Hz L4 Channel 1 of NORMAL i d 18 9 E 66 7 3B L A pM M V M MM V VN NN n PHONS EZ 3 LOC al TACH H H SPEED B d M Hz b BK Hz ret bed crar INITIAL ROOMS usREPM STHT Mx S5rPec F TREIG SETUF FILES AUTOSTR The display will be separated into two sections the section on the left shows the created memory files the section on the right displays the files that are stored on a floppy disk if the optional floppy drive is attached If no
135. EL surface volame ETH SPL 6 2956 ai ie Wai Gah O TC ROS DNA dS qu ran NECS NM ere TE A A QU QA DITE aT QE CE aed VES MET E A PUDE E EXF HEHT T DL 1 78 Dual LIHEHE 28Hz 28k Hz STOP zl FEB 95 B 13 48 5L ne oe wi ite ae RE Gu RPR Gee N at RT ae N Ae a es lei N a ed AEP AD Ue Hee Ge Se om Ge a a a 8 FILTER 15 31 5 Hz L 1 l S Channel 1 of 2 HORAL E fe ee RT ee HOISE LRT TER TD R 39 5 FEM TACH H H SPEED B d 0 H DG H HZ dotted crar ROOMS SET A SOURCE RECEIVE BACE GD CLR PG 5 Press EXIT to return to the Main menu Noise Rating Curves NR B The Noise Rating NR curves are used in the same manner as the Noise Criteria curves but are used to measure noise in con formance with international standards NR is obtained the same way as Noise Criterion and is found in the Rooms menu e gis 975 23591 HC HF EL surface volame ETH SPL 6 5356 Bh A uBR ae Sah ae ake ee UR ate a EXF HEHT T DL 1 E Dual LIHEHE ZzbBHz zEkHz c ap 21 FEB 98 Hr 19 48 5h ON DC EP E RR A A A EN FILTER 15 al 5 Hz L 1 uc dl 1 of 2 yee nae rra TEE a c HOISE LRT TER TDK R 39 5 TA H BH SPEED B a 0 H DG H HZ dotted crar ROOMS SET A SOURCE RECEIVE BERHCK GD CLR PG Room Criterion RC C 9 36 The Room Criterion procedure is can be found in ANSI S 12 2 1995 In addition to producing a single number rating of the steady background noise the quality of the spectra is described in terms of on
136. ES AUTOSTR features provides information on frequency content of sound many standards based on 1 3 and 1 1 octave bands easy to see trends or patterns limitations cannot isolate specific frequencies pure tone Basic Acoustics 2900B TRAINING MANUAL FFT ANALYSIS AS TES 1493 75004z HSAA annel 1 of 2 NORMAL 66 2 Z 68 9 TACH 8 8 SPEED 4 6 TP PEA PA 1 SE eel ROOMS vsRPM STAT Mx Srec F TRIG SETUP FILES AUTOSTR e features provides information on specific frequencies excellent tool for troubleshooting Basic Acoustics Using the Model 2800B 2900B as a Sound Level Meter in Standard Analysis Mode One may wish to use the 2800B 2900B RTA to measure Sound Pressure Levels in the Standard analysis mode Although this method does not meet ANSI 51 4 1983 or IEC 651 or IEC 804 standards for Sound Level Meter instrumentation the results will be sufficiently accurate If you are required to comply with Sound Level Meter standards the SLM analysis mode of the 2800B 2900B must be used Setting up the 2800B 2900B For this example we will use the Standard Single Channel anal ysis mode of the Model 2800B 2900B It should be understood that using the Standard Dual Channel analysis mode of the 2900B will provide two channel measurements of Sound Pres sure Levels Before we begin setting the parameters in the RTA SCREEN SYSTEM EXIT 2900B TRAINING MANUAL connect the microphone preamplifier micro
137. ESET 26 FEB 98 18 47 46 L FILTER 14 25 8 Hz L Z Channel 1 of 2 HORMAL 60 ECT e E RRR da RN RRR RTE RRR RR RR RIRE Ga de R R FE Ph 65 zm n B As REM l TACH H B SPEED B B dt 2021170011727 9271011 2721017101112 a L EFTIR meee INITIAL SINGLE DUAL QUAD fo Single data display window Two data display windows Four data display windows This will display a reproduction of the display on the analyzer 2 29 2900B TRAINING MANUAL 4 Press the OFF A key when finished using the external mon Q 1tor A MU I A IFF J AO loners hh tapas SPL A em 140 r WX A A R 7 A E 19 a A A a 0 RR EXPOHENTIAL 1 Dual LINEAR ZzBHz 1BkHz RESET 7A FEB 98 14 47 46 SH wu cx RE A RR RM anser at uh p ee ae det aes Jen ee FILTER 14 zh Q Hz Leo dE Channel 1 Cee Z ST eB DP prp EM DIFF Ph 55 9 Sn i 6 85 l I THERE 000 SPEED 9 9 25 z z B z dotted crar IHITIHL SINGLE DUAL BUAC LCD 5 Press the EXIT hardkey to return to the SYSTEM Menu EXIT Resets You can reset data and setups stored in the internal memory of the analyzer To reset data or setups 1 Press the RESETS P key 1 1165 16 83 17 Chanls SLM A STANDERD CROSS IMTEMSVY UNITS FILTER CLASS 15 E RR RTE A A A RR RR A Be ee O R RN cae ae ee eae N SPL EB BEBA 3H r K R TR 5 R RTE TR R A R R RTL NT NE R a a de A EXPOHENTIAL 148 Dual LIHMEBR 2BHz 26kHz RESET 19 FEB 98 16 65 45 TA r ae e R R e A a o A e i ie a can
138. ETUF FILES AUTOSTR 2 Press one of the following keys A C to select the desired analog weighting e 22d ad A WiGT CGT 26 26k note SPL 22 6168 38 Kr E E G p MEER TRT RTT AE RC C r O RA LT TTTE Inrut 1 SAT STOP az JAN 93 2312219 YA E ZBIK HZ G d 34 6 Max 62 8 SLM DATA li SLOW FAST IMPULSE LEQ srar sETUP FILES AUTOSTR B 8 5 2900B TRAINING MANUAL 3 Press of the following keys I L to select the desired detec tor Any of these detectors may be selected prior during or after a measurement is made The data for these detectors are measured simultaneously 2 JAN 23 24 04 R MGT ERT 20 28k note E SPL 22 8188 aie aD II aa aa set da af Bete UE Inrut 1 STAT STOP 2 JAN 98 23122199 NAS 20Hz 20kHz FAST EUREN D Hin 34 6 Flax Sa 68 4 ranae 115 STAT SETUP FILES AUTOSTE 4 Press the RUN hardkey to begin the measurement 8 6 CHAPTER Room Acoustics Among the many built in capabilities of the Larsone Davis Real Time Analyzers a very important and useful tool is the Room Acoustics feature Acousticians that are involved in determining decay times of rooms theatres etc or in analyzing the absorp tive qualities of walls doors barriers or partitions will find the Room Acoustics capabilities of the RTA s to be very complete These types of measurements require only a single channel ana lyzer such as the Model 2800B Using a dual channel analyzer like the 2900B
139. F Ph 124 2 zns 343 69 FEM TACH Ha SPEED B d dotted crar INITIAL Pink noise has equal energy per percentage bandwidth e g octave or 1 3 octave As with the sine generator the level is set using the softkey LEVEL E and entering a value between O and 9999 using the numeric keypad 2900B TRAINING MANUAL The keys lt ATTEN G and gt ATTEN H will produce attenuation or reduction in attenuation in 20 dB incre ments also as described for the sine generator When 1 3 octave digital filters have been selected the generator can also produce 1 3 octave bandlimited pink noise From the Broadband Pink Noise Menu the Band limited Pink Noise Menu shown below is accessed by pressing 1 3 A 20 TET 18 82 11 WIDE OH OFF LEWEL amp HTT ATT SPL T2 42548 EXPONENTIAL 1 8 Dual LIHEHE 2BHz 24k Hz STOP z FEB 98 16 61 43 FILTER 24 zoH Hz Lx Channel 1 of 2 HORMAL d DIFF Fh 185 9 5n 54 56 TACH BH SPEED B a dotted crar BOTH SOLID DOTTED As with the wideband pink noise the key LEVEL E is used to set the relative output level of the signal and the keys lt ATTEN G and gt ATTEN H are used to add and remove attenuation at all frequencies in increments of 20 dB The keys ALL I and NONE J are used to turn On or Off the noise in all 1 3 octave bands simultaneously The On Off status of the noise in individual bands can also be set on a band by band basis using the keys ON C and OFF
140. F FILES AUTOSTR 11 27 2900B TRAINING MANUAL 11 28 46 Press COHER D to display the coherence function The coherence function is a measure of signal to noise ratio and is an indicator of the quality of the measurement A good coherent measurement has a value at or near one all the way across the frequencies of interest except at anti reso nances S Je 22 15 46 ALSPECT C SPECT amp s FEF TIME DISPLAY note DETECTE F bd eee ae ee ee eee ma EM COUNT MARLIAL ACCEPT ual LIHEHE 1Hz 1BkHz STOP ar JAN 93 22164135 N E Sra E H E E E ET N NN RO e O A FEEL AZ 1258Hz ESHH Coherence D z d A 9565E A A Base Fre aLern y A lt ARR 164F td Ch2 Bad FEM TACH B d EED B d Eig E dE H Z A bU ofset DG IHITIHL HLTEEH EBlJHCOEP Fe gt R T TEIG SETUF FILES AUTOSTR Acoustic Intensity Why use Acoustic Intensity PY e Determine the Sound Power of a noise source e Locate and rank sources of the sound Sound Pressure versus Sound Power e A sound source radiates Sound Power The result is sound pressure e The perceived Sound Pressure is dependent on the distance from the sound source plus the measurement environment 12 1 2900B TRAINING MANUAL Sound Power Analogy e A heat source heat
141. FEB 00 50 46 Last M 118 O dmi MAXIMUM 9001 Baez at r K RR RN RRR K RR NR RR RRR NR R K R RR NR RR RR N NR RKR R RN RR KK RR N N EXF HEHT IHL 1 78 bTIME Dual LIHEHRE 2H8Hz zBkHz STOP 24 FEB 98 26 10 14 TH PE ecg nde AS EA A NR tt ffe are as FILTER 14 75 8 Hz Leo M Channel 1 of 2 HORMAL 3r H 35 5 DIFF Phs 13 5n 18 35 TACH B B SPEED B a recall data DOOFUS lt Press the numeric keys and horizontal arrow keys to enter the range of record numbers of the autostored records to be applied in the Block Maximum function 10 Press the EXIT hardkey 1 35 2900B TRAINING MANUAL 1 36 EXIT In the third line down on the right hand side of the display the word MAXIMA will appear indicating that this autostored record is a maximum record ark B1 33136 W Fall E AWE E MA B SUM vzTIME KEEP Hate SFL MASIMA EXPOMENTIAL Dual LINEAR Z8Hz Z kHz STOP 24 FEE ee z4 m 1 Hz EK HE Channel 1 aie z Pa Hs DIFF Ph 72 9 Sn 3 82 TACH Ha SPEED B d hrec all data s z z DUUE US DELETE H Preu A Hest 11 Press the EXIT hardkey if you are finished viewing the recalled data to return from the Recall Menu aa gct Ba Gaig W Fall B AWE wsTIME KEEF i Hate TEST 1 l SPL AVERAGED an he lide qeu Rex a A ee NOX ar let mo ES X Ce NCC HE CACTUS US S QN Ll er EXPONENTIAL bT LINE i Dual LIHEAR 2BHz zB Hz i RESET 64 OCT 94 88 53 55 TA ra Be cet ee a we ae a a AAA a a AAA
142. FEQ 1 2566Hz HAA Channel 1 of 1 HORMAL g 2 7 E 2 4 TACH B 8 SPEED B a dotted crar BOTH SOLID DOTTED 2900B TRAINING MANUAL 8 At this point we should take advantage of the RTA s hori U zontal expansion feature This will expand the display so E that the calibration signal can be viewed in more detail Press SHIFT and then H SCALE E to activate this feature 14 E 19 56 98 AXIS YARIS U SCHLE U FSET H OF SET FFTZ00M E 19 2909 EXPONENTIAL 1 Ineut 1 LINERE 1Hz i kHz STOP 14 APR 94 15 54 16 i 8686Hz HSAA Channel 1 of 1 HORMAL d 33 2 B LOL A wor 3 Tow o9 dn TRCH 8 a SPEED 8 a iE DG dotted cear IHI McSTOP McWAIT McREPT Eat SameREF SetREF vsREF 9 Within the H SCALE menu you have a number of choices S for the scale multiplier Choose 4 C to select the 4 times mul C tiplier 14 APR 16 01 34 i 2 g SH SELECT Horizontal Scale Hote 2 4568 G EXPONENTIAL 1 8 Ineut 1 LINEAR iHz 1HkHz STOP 14 APR 94 15 59 26 H 81 2586Hz HSpp Channel 1 of 1 HORMAL d 73 4 B Y3 5 TACH 6 8 SPEED 4 4 dotted crsr The display is now expanded by a factor of 4 Since we plan to enter the calibrator level 1 0 g in linear units we need to change the vertical scale to linear from the default loga rithmic scale 10 Press SHIFT and immediately select Y AXIS B SHIFT 14 APR 18 82 55 X AXIS Eras some U OFSET H SCALE H FSET FFTZDUM G 2 4506 1 5
143. FRE Auto Al note 2 BEBE id cr ROOMS lthresh hthresh A Prev B Hext DHTH SOLID DOTTED BOTH 9 13 2900B TRAINING MANUAL EXIT RESET R S CLEAR RECALL 9 14 7 To see the sound decays of the other frequency bands press DATA M 2B S 15 15 18 RT66 REPLACE AVERAGE Auto RE Auto Al note i Hotes SPL B See LIMEAR REPEAT B H564 eri a Lz 63 3 s FTE JHB ct B 6560 AutoTH Max a A gt E o EY Ley 9 8580 2 Berens solid crar ROOMS lthresh hthresh A Prey A Hest CDATA SOLID DOTTED BOTH Then press the right or left arrow hardkeys to step through the different frequency bands 28 da 15 17 82 RT6H REPLACE AVERAGE Huto RE Auto Al mote Hote SPL B See LIHEAR REPEAT B 588 Dual LINEAR 26H2 18kHz2 RESET 28 Fees Be Br CATA 32 523 Channel 1 vETIME Ls 3 Ts 9 9209 ETEO 9 990 ct 8 8588 AA ATH Max 25 8 5 Lea 36 1 1 2 BDG new data ROOMS lthresh hthresh H Prev H Hext CATA SOLID DOTTED BOTH Press EXIT to return to the amplitude vs frequency Press EXIT again to return to the SYSTEM menu Note that the measurement display is cleared It is almost always desirable to make a number of Autostore RT60 measurements within a room and average them together to come up with a single averaged measurement This helps reduce errors caused by background noise room modes dead spots etc Move the microphone to a different positions and repeat the measurement
144. Guns EECEIUE BEHCK GD CLR PG 22 Recall the receive room spectrum by pressing the RECALL hard key and locating memory 9 Now push the KEEP H key to keep the spectrum and return to the Main menu CLEAR RECALL c 23 FEB 14 84 21 W Fall B AWE B MA E SUM KEEF 1 y Te eee ee ee ee ee ee RECALL Normal Hate RECIEUE HUE SPL AVERAGED o LINEAR SINGLE 29 9 al LINEAR 26Hz 26kHz RESET z3 FEB 98 10122135 FILTER 14 25 8 Hz Led WE Channel 1 S Z POR MAL DIFF Ph 84 8 Sn 22 35 TACH Ha SPEED B d hrec all data REM H Hz ROOMS DELETE 9 32 E EXIT c 2900B TRAINING MANUAL 23 Return to the Rooms menu by pressing ROOMS Y and enter this receive room spectrum by pressing SET L and RECEIVE N 23 FEB 14 88 81 HC HF EL surface volame ETE 140 gt O A RAS RA FOOM CATA SET Hote RECIEVE AVE SPL A Bh r ANN a sen Sah Se VE SIHGLE REM TACH B B SPEED RAGED BEBE zB LIMEBR 258Hz zBakHz 10 22 38 RESET 23 FEB 98 SERERE stt EE 6 i cA D uA Sod ulli es FILTER 14 25 6 Hz Les Channel 1 of 2 NORMAL i d 45 2 H 67 8 A e o y IIA DIFF Ph 84 8 5n 22 35 B a tthed crear H Hz Eod Hz hdo ROOMS SOURCE RECEIVE BACE GD CLE PG 24 As part of the Transmission Loss and STC calculation the surface area of the partition in square meters and volume of the receiving room in cubic meters need to be factored in as part of the calculation Press surface D
145. H BH SPEED a a ae 138 H Hz E Hz Hz INITIAL 1001 1ne Sealine 4661 ine saa ine FFTZOOM WIHDOL BASE Ed 3 Press the EXIT hardkey to return to the System Menu EXIT For FFT Analysis perform the following There are three parameters which must be defined to perform an FFT analysis the number of lines the window type and the full scale frequency 1 Press one of the following keys to select the FFT analysis mode and the number of lines Note H4AA designation when 400 lines is selected 100line I 100 line FFT 200line J 200 line FFT 400line K 400 line FFT 800line L 800 line FFT single channel only 13 or 1r 85 129 leloct 9 lesoct lona short reverse SPL 41 5668 TH ditio ELA Eo ane ORC ea USE N Yat ia N T sae CRI RE R ha RT DL OUR Ges SET AE CO e oe tac qos Meese Seca Xo en Aten ca N dx EXPOHENTIAL 148 Input 1 LIHEBE 28Hz 26kH z i 15 PER Brol EINIR ss s ss s 3Go 0 B BoG G3 G G9 G GG G o33 83 83 73 37 BN BN G3 C3 3 3 83 BN B 3 83 BN 3 3 M 3 3 3 3 3 S Channel 1 of 1 HORM d 47 9 B 65 4 FEM TACH 6 6 SPEED B d AG HE nn 55 5 5095 51 lt T5 dotted crar IHITIHL 1661line gt 88line 40 line S6GlineJFFTZOOM WINDOW EASE Ed 2 1 2900B TRAINING MANUAL RECT A HANNING B FLAT C ZEROPAD D IMPACT E EXP 2 F EXP 4 G EXP 6 H 2 8 2 Press the Window N key to select the desired time weight ing window 19 32 17 03 19 1rloct 1 Zoct lona short reverse 41 5
146. H EqIHORM PR ALIAS B SETUP FILES AUTOSTR il SIF jirdizdd O EARCT C SPECT FELE LCLHEL TING LICA O noba DOLTAETE cee FLASTIC TIP TU HERR 3 De TEn E isi uento TALH 6 9 EPEED PM ME ed Lois and AE ae EM ALTERH EAHDFPf4 Pa gt k s SETUP FILES AUTO b ILFEL CK nnb2 OLTLCTE acia STEEL TIF En TU HEBR af d Dee REEL T uec TACH EPEED H B zB HADE toth rraerz ALT EF H EAIHDR A Pa gt k s SE TP FILES AUTOSTR 2900B TRAINING MANUAL Impact Hammers Double Hits Double hits occur when the hammer strikes the test item twice Double hits render the measurement useless Double hits are difficult to avoid at measurement points on the test item that exhibit a lot of motion at resonance Impact testing is easy but does require practice and tech nique Pulling the hammer back or letting it recoil naturally after impact helps 11 SEP 11 54 54 H SFECT C SPECT amp FEE COHER TIME DISPLAY note DETECTE seil E aT LEF Bi d DG E NO T E TE TTT A Loe oe ay at esa uae a COUNT STHGLE 4 DIRECT LIMEAR 1 3 2kHz RESET 11 SEP 92 11 14 38 BS Sa 1 cce ee ee ee TIME ee ABBAS ESAA lleiohted Tim D i g 5 57r E 39 REAL u 87 gt 3 X 03 03 0830 3 83 03s 9 03 03 834 3 89 35 89 8 95 89 B8 3 83 3 83 3 3 3 93 8 98 8 B8 8 98 8 93 85 83 3 3 3 3 3 3 3 Base Freauencu LOC _ TACH 8 8 SPEED 4 6 Dp 0000 200M 1 r3 68r9 E A dotted crsr ALTERH BWHORM Pook ALIAS T TRIG SETUP FILES A
147. Hrida l7 OFF bra T IME delta endstor note KL S748117 OFF buTINE delta endstor SPL B ABBA 2B LP UITITTTUUTIE EXPONENTIAL 18 TIME Dual LINEAR 20Hdz 2Bk Hz RESET 4 OCT 94 75465 12 CEN Nu ay ae Re ee ee ee ee ee pes A A FILTER H 1 15 Hz Les a ae lof 2 ao r A E E E E E PHONES 54 3 i l L TACH BH SPEED BH F z s dotted crsr bBSTACH TACHSET F TRIG FILES INITIAL The message END TIME XXXXXX XXXX along with a flashing cursor will appear on the upper right side of the dis play The END TIME indicates how long the measurement will run Upon reaching the selected END TIME the ana lyzer will stop the measurement Ad OCT 87258 2a 1168 gg F 1 8 BTIME Dual LIHEHE ZkHHz 2zBkHz RESET H4 OCT 94 av 43 1z A Ft ed wow ve x US apt d e t Prev Te ee S e Y UU UE CR car a Teo det ko Ven ae ovdi Dp del Ver ju FILTER H 1 2A Hz Leos MERI 1 of 2 a r A PHONS 54 3 E l L TACH 8 8 SPEED B B dotted crsr INITIAL 6 Using the numeric keys of the analyzer enter the desired EXIT value in seconds for how long you want the analyzer to store data Then press the EXIT key 7 Press the EXIT key to return from the AUTOSTOR menu EXIT 2900B TRAINING MANUAL 8 Press the R S key to begin the Autostore The message RESET Autostore in progress will appear on the upper right of R S the display 44 OCT 875525 BZ HORMAL Lex MIH MA 5 SRL pb k S5 pes zuo ovr UE QI PLEXUS Uh Sata GSE d
148. Hz Les TF PONER 1 d 13 8mm d Ffe 7t 264 DELE Z Ke rg 56t A Ye 6tdEPU JOB_ TEST PART FRONT AREA 797997777 S QG Hz 5 doatted crar HITEST S2J0B S FART 5 HREEH CitF4 2 CzxFd z F3 FZ 22 Press Power A to perform the sound power summation note E En FEROHT plu dE BEBE LINEAR STHGLE ZD Bi Dual LIMEHR 258Hz 18kHz RESET 13 IHH 93 mag 42 41 FILTER 25 315 Hz Les TF F 1 d 13 8mm d 09 CT Did ARE E amp r39 5t A rS 6ftdEFW 25 8 Hz 566 Hz 104 BkHz E A dotted crar HITEST SJOB S FART S AFEA S EDIT CitF4 2 Czx Fd z F3 FZ On the display you will see the total sound power spectra of the specified job part and area 13 aa 41 48 19 Power F2 P I F3 WPP F4 FHU note Hotes dE Pl 26 Baia LIMEAR SIMGLE 26 515 Dual LIMEHR 26Hz 18kHz RESET 13 IHH 93 mag 42 41 FILTER 25 315 Hz SE ka BS 1 d 13 6m 3 54 ali Bade g 1t A 67 9tdErll TEST FART FRONT AREA PO L NT 1 25 8 Hz 566 Hz 16 6kHz E H dotted crar HITEST SJOB S FART S AFEA S EDIT CitF4 2 Cz Fd z F3 FZ 12 31 2900B TRAINING MANUAL 12 32 Autostore Du TACH vsRPM Display and Order Tracking The Model 2900 has the capability to acquire data as a function of RPM speed utilizing the built in tachometer input feature This is very useful when measuring vibration or noise from a device that has a variable operating speed such as a turbine transmission etc For this exercise you will explore the vsRPM featur
149. I HH STRHDRD CROSS IHTENS UNITS FILTER CLASS SPL B ABER 38 r Pe EXF HEHT T DL 1 78 Dual LINEAR ZBHz ZBkHz RESET 19 FEB 923 16 65 46 79 IT FILTER 14 25 Q Hz Leo O 1 es a dis N D DIFF Ph 52 28 Sn 2 4z REM TACH 8 0 SPEED 4 4 Li AA AGL a eee ere Gayl CEEERR E TUS Ae os He 20 kHz dotted crer IMITIAL I O SIG GEN INPUT clock COLOR MLS FILES RESETS 2 Select the desired baud rate by pressing one of the keys J P The message RS232 XXXX BAUD SELECTED will appear on the upper right of the display The XXXX indicates which baud rate you have selected Eo ee ee L 6 0000 ro VV ERF HEHT T HL 1 8 Input 1 LINEAR ZbHz ZbBkHz RESET 19 FEB 323 17 88 38 JB moro on nomo 3 NON RON o n a m og m 3 3 2 2 3 rs n n 3o 03 O3 o3 n og mom m os sm on on ll EE HARAHZ HSHH Channel 1 of 1 HORMAL d 33 9 6 6 SE moror on p m oa 3 93 3 2 2 3 s n 4 9 3 3 3 2 3 3 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 5 REM ot II TRCH 4 8 PEED 4 8 INITIAL 1299 4990 S600 19206 3 Press the EXIT hardkey to return to the System menu The EXIT analyzer is ready for communication to a peripheral device 2 10 2900B TRAINING MANUAL 3200RC Remote Control The Model 3200RC Remote Control Module communicates with the Model 2900B through the RS232 interface 1 Connect the 3200RC to the serial port of the analyzer 2 Press the 3200RC A key to enable the remote control mm wo Tl m m mm
150. IAL 1 i Cual LIHEHR 2bHz 24kHz STOP AS OCT 94 15130142 3B SF NurlEERO m o oo e n n n n ln n nS FILTER H 1 SH Hz Le 3 l Channel 1 of 2 NORMAL i g B 66 2 3B 21b lc MS A PHOHS BZ 3 TACH 8 8 SPEED 4 4 Li EIC H After pressing one of the softkeys J P enter the desired setup name Press the Shift CLEAR hardkeys to delete any entered text For this example enter the name NOISE by pressing the alpha characters appearing on the display S S 16 12 28 H E LC D E F G H Enter zetur name eae 906 T MT NR A a Soa RI E EXPONENTIAL 1 a i Dual LIHEHR 2AHz 26k Hz RESET ad OCT 94 16 85 24 B BOE a a xr Tas ea Vel d qe A a JE N Qe p EDU JANE del xn we Woe N wd d ar de US Vel qe e s e du FILTER H 1 15 Hz Le 3 Channel 1 of 2 HORMAL A 34 7 d IW A fava Uu A cay csi ccc uio PHOHS be 5 l TACH 6 6 SPEED ALG E bU offset B o P H H EXIT 2900B TRAINING MANUAL Press the EXIT key after entering the new name The new name you entered will appear on the softkey that you previ ously selected See figure below B3 cre 15 43 59 name R SETIUF STORE B00T note i SPL 14 5568 TH wb E ee tae See te fe Rn Sel a es Swe ea og RA oe er See ae DR R Br ce CAR EXPOHWEWT IAL 1 A ual LIHEHR 2AHz 26k Hz STOP 63 OCT 94 15 38 42 FILTER 1 56 Hz L 3 Channel 1 of 2 NORMAL d B 66 2 PHONS 62 3 TACH 6 8 SPEED 4 4 a C3 E un Gl Gi m SS ar ES na a H A Hz a z d
151. IN is the minimum rms level that occured during the measurement period LMAX is the maximum rms level that occured during the measurement period level dB Basic Acoustics L BASIC SLM MEASUREMENTS LEQ amp SEL Leq is the equivalent continuous sound pressure level the average SPL SEL is the sound exposure level It is the acoustic energy of the entire sound event compressed into 1 second 1 second Basic Acoustics 2900B TRAINING MANUAL LS SPL AND LEQ MEASUREMENTS Sound Pressure measurements done with a sound level meter set detector rate to fast max hold feature is handy for capturing events Leg requires an integrating sound level meter Leq is a single continuous dBA level that would produce the same acoustic energy as the actual noise history often measured in interval hourly Basic Acoustics LS STATISTICAL DESCRIPTORS Ln is the sound level in dBA that was exceeded n ofthe measurement duration done with an environmental noise analyzer used to characterize non ambient events level dB Lg LMAX Eon AS Loo Re Lino LMIN fee time Basic Acoustics 2900B TRAINING MANUAL Ho FULL OCTAVE AND ONE THIRD OCTAVE BANDS Basic Acoustics L OCTAVE BAND ANALYSIS SEL DISPLAY note DETECTR 6 8700 co o gt o DEE a e 9 8 Tal eo srs ears 28 0000 4 qu Z H dotted_crsr STAT Mx Spec F TRIG SETUP FIL
152. Infut 1 LINEAR 1Hz 16kHz RESET 15 OCT 94 2Bh 11 27 44 dq PER IE R O E A May IM a TR N c c EE M FREQ Ae HARAH H4HH Channel 1 of 1 HORMAL d 95 2 E ED SR R R RE Oat Ge RN KAR i Meme RRR gat R R NTR RR ATR NR RE R RRR TE a TACH 6 4 SPEED 4 4 aa BEE 00m 1 5000 0606 dotted crear IHITIHL sjscale s srFan s amin s amax FADAR f RADAR m Type in 20 RPM as 00020 0 to establish this minimum delta value 15 EN 2115114 e IMIMUM Baza d 5 BERE 2H REOR E Cake Gael tare o o NN A o a ee Se a a le Seek E Eu EXPONENTIAL 1 64 bTACH Infut 1 LINEAR 1Hz 16kHz RESET 15 OCT 94 2511527 44 RRA AN RA E E M FREQ A ARRAH AAN Channel 1 of 1 HORMAL d 95 2 ED UO UO e PVRS A Eo ce RR KR R YN R RKR N RR RR a ae R RR e E E DP l TACH 6 8 SPEED 4 4 BB dotted crear INITIAL Next press t Amax D to enter the maximum tach delta entry field 15 ES zl 321 12 t scale t sean t amin cenas e ineut AC al SLOPE ANG Tach inrut Jack G EB HHHH z0 TENA a A ESFU HEHT L HL 1 64 bTACH Ineut 1 LINEAR 1Hz 16kHz RESET 15 OCT 94 28 11 27 a B gR RRR LRR rU se R RE RRR Ga a EN a Se ce FREQ Ini ARAAH ae Channel 1 of 1 HORMAL d 95 2 6 RR R KK a a 2711111171021 LOC i TACH SPEED 4 4 Ba dotted crar IHITIHL s scale s srPan s amin s amax EHDHE f FRHDHE m Type in 1000 RPM as 01000 0 to establish this maximum delta value 15 OCT 21 32 37 BE alas IMUM 41606 4 B did
153. L d 43 2 1 5 TACH 85 8 SPEED 4 4 S i dotted crsr UIEi dE ell SPL G under undet undef Under Under Press the up or down arrow on the keypad to optimize the range One way to do this is to range down one increment at a time until an overload is reached Then range up one or two increments 21 Le 63 19 43 SLOPE name SAME E UNITS Hoise F mU cal U cal level zm G 51 3600 5H B A PA A Bose fe A A AAA EXPONENTIAL 18 i Input 1 LIHEAR_ 1Hz 18kHz RUH 21 MAR 94 09 15 54 me A E IDP AIHH FREG 66 anaadz Hahn 3 5 Channel 1 of 1 HORMAL g 4 9 E TACH 6 8 SPEED 4 4 E dotted crsr LITE dE el under undet Under Under Notice the prominent signal at the calibration frequency 81 25 Hz After the signal has stabilized press R S to stop the measurement z1 bod ON 165 Se SLOPE name SAME R LUHITS Hoise F mU cal U cal level 3 9288 ERF HEHTIHL 14 8 Ineut 1 LIHEHEF 1Hz 1i kHz RUH 21 MAR 94 09 16 27 E AN ae FREQ Bm ARRAHZ HS8HH Channel 1 of 1 HORMAL d 43 7 E 1 9 TACH 6 8 SPEED 4 4 i s dotted crear UIEi dE el SPL G under undet undef Under Under Move the active cursor to the calibrator frequency 81 25 Hz by pressing the horizontal arrow keys You can accelerate the movement of the cursor by holding SHIFT and pressing the desired arrow key at the same time zl MAR 09 21 02 SIS E 27 5200 EXPONENTIAL 1 3 Ineut 1 LINERE 1Hz 16kHz ELIH 21 MAF 94 09 20 32
154. L 1 E Dual LIHEHE ZzkHz zEkHz RESET 11 FEB 93 sra areal TH D uM ih eh Gea watts Sak dd DA wal nde Ga Teme Mawes ged RE A ela Jee E EE FILTER 1 z5 L E Channel 1 of Z HORMAL d 23 56 H 34 9 aB r ENTM IE SAR ae NTR de LC R R R I R IE RT L ini tan gy A A AN DIFF Ph nz E Sn Ta 43 CE ogi TACH BH SPEED Bg d A bl Hz dotted_ crar DIF clock COLOR MLS FILES RESETS 5 Press the appropriate keys OV A 28V B 200v C to select the correct Bias voltage for your microphone For Larsone Davis condenser microphones select 200v EE Bpz g4 45 Bu 25 U zag L AUTO FH Ineuts TEST SPL EB Ela at r T RR A A EXPOHENTIAL 1 E Dual LINEAR ZBHHz ZzB kHz RESET 11 FEB 98 Hi1 57 51 79 E E RA AE DA A TE EE Se ac 2201141002731 7 FILTEF i4 Pj Q Hz L 3 Channel 1 of Z HORMAL d 23 B 3 54 r IN AR E TR E R RR O O TA DIFF Fh nz S Sn z 43 REN ae TACH HLH SPEED a El 25 Z A z datted crar DIF HUG T C HET 1 2Bk zH 2Bk 1 16k 26 16k SAME aRAHGE 6 Press the EXIT hardkey twice to return to the Main menu RESET R S AUTO RANGE CURSOR EXIT 2900B TRAINING MANUAL Press the R S key to RUN or STOP the unit You can verify the status of the unit by looking on the right side of the dis play B en 14 23 49 WORMAL Lex MIH MAH SEL DISPLAY nate DETECTA i SPL 15 1188 TH k ae E A RN lea 1 A LIHEHR 2AHz 26k Hz 63 OCT 94 14 23 34 54 oe ea ae eee eee A ra vou ERMIB a a ed ER 4 1 NE Hz L
155. L B BREE 140 A AD e a A AE KK ES te EXF HEHT T DL 1 78 Dual LIHEHRE 2H8Hz zB kHz RESET 26 FEB 93 95 265 51 ai dO I M A O ui ci FILTER 14 75 8 Hz Leo Channel 1 of 2 NORMAL d 34 4 H 3 By ER KERE a ol 0 DO e DIFF Ph 65 A Sn 6 85 REM gi l L TACH 0 6 SPEED B B zn z S z dotted crar INITIAL AIS TART alEHD LIH Z Lone Huto L FILTER 2 18 O 2 I X 2900B TRAINING MANUAL Dual Tone The signal generator has the capability to activate a second tone that will sweep simultaneously with the original tone To look at the signal generator output on the screen you will have to put a cable between the Sig Out on the back of the 2900B to one of the 2900B inputs l Press the 2 tone N key to activate the dual tone m 03 01 65 Fstart Feng E Se R ez Lee Les lt ATT gt ATT FL EB AGHA 190 A UE EORUM Je ky R CAUGND A E ees A A A AA EXPOHENTIAL 148 ual LIHEBRE zBHz z kHz ESET zB FEB 98 8 36 55 24 S E A EUM rc RN FILTER 14 275 48 Hz Les Channel 1 of 2 NORMAL d 34 4 A 46 3 AH r We A E 7 dr RTE A A Se Seu ver VEU UNI E a A BP cee mer rt RAS d aah 9 CIFF DPs AS a 5n 6 85 BEN ag l TACH H H SPEED B d zB Hz 6360 Hz zH BEHz L dotted crar IHITIHL aS TART alEHD SHEEP LIH 2 tone auto L FILTER J Press the L1 G key to adjust the level of the first tone E 03 45 56 Fstart Feng E Se R ez Lee Les aF SPL 116 1655 EXPONENTIAL 1 3 Dual LIHEHE ZzbHz zEkHz ETOP 7H FEB 98 995 d95 16 FI
156. L E GbR TH CaL LL LC I EE cela ae LINEAR FEPEAT A BSA bT IE Dual LIHMEBR 26H 16kHz RESET 26 FEB 98 13 51 27 zB r ac a Ga R RR a OR OR A bad aR ELE a a ae K FILTER 14 25 8 Hz m4 Channel 1 of 2 HORMAL 5 7 B 25 4 AB Cr BIFF Pbs Za 1 Ens 44 SED TACH 9 9 SPEED B d z z z datted crar ROOMS b THCH TACHSET F TEIG FILES 14 Type in a delta value of 05 seconds as shown below 26 FEB 13 39 32 20 DELTA TIME Gba 22612 7B ppc A ME LIHEAR REPEAT B BSBB Dual LINEAR zHHz lUkHz bTIME La RESET 26 FEB 92 13 31 27 JO r te Comets Sat R Gi me A AN ETE PE FILTER 14 75 4 Hz Sri Channel 1 of Z HORMAL d x B 23 4 3B S A iocis CR URNA A EZ Eger SELORL RN SEL NEL SEE SES Ric RR CEDE BIFF Fh 2 1 n dd REM g l I TACH Ha SPEED Bg d dotted crar ROOMS 15 Press EXIT to enter this Autostore delta time Now that the Autostore measurement parameters are estab lished let s review what will happen during the measurement You will drive the room with pink noise until it is excited at all of the frequencies of interest You will then begin the Autostore measurement by pressing R S on the RTA At this point the RTA will start capturing spectra at a rate of 20 per second every 05 seconds After 1 second the noise genera tor will be shut off due to the way the noise generator is config 2900B TRAINING MANUAL ured but the RTA will continue to capture spectra as the room abso
157. LTER 14 25 6 Hz L 3 Channel 1 SL z HORMAL d H DIFF Ph 121 2 Sn 278 82 TACH BH SPEED B a s z z S dotted crar IHITIHL aS TART alEHD SHEEP LIH tone Auto L FILTER The Sum Of The Relative Amplitudes Of The Two Tones Are Set Equal To One So The Relative Amplitude Of The Second Tone Will Be Given By The Relationship L2 1 L1 Setting L1 To 0 5 Will Result In Both Tones Having Equal Amplitudes Once Setup Both Tones Can Be Swept In The Same Manner As A Single Tone K Press the AF H to select the separation in cycles between the two tone 2e FEB 09 48 56 Fstart Fend R se R es Lse Les Li SPL 116 7858 EXPONENTIAL E Dual LINEAR 2 Hz 2akHz STOP 7H FEB 98 995 d95 16 FILTER 14 25 8 Hz L 3 ue Channel 1 UE z d ue DIFF Ph 121 2 Sn 278 82 TACH H H SPEED Bg d S z z a dotted crar IHITIHL aS TART alEHD SHEEP LIH tone Huto L FILTER 2 19 2900B TRAINING MANUAL PINK J 2 20 L Press 1 tone N to return to the single tone mode ea 69 48 56 Fstart Fend R se k es Lse Les L1 aF SPL 116 7656 148 A SD NR RR RR RN RR A R R NR A SE a ae Ge ae R Pi ead E ua 1 LIHEAR 2BHz zBkHz STOP zH FEB 98 89 45 16 125 orm m or n n Bg e B Bn BgW nel lBnmkB eee FILTER 14 25 4 Hz Les y Channel 1 of 2 NORMAL d x H DIFF Fh 121 2 Sns 218 52 REM TACH 6 8 SPEED B a ai EROR AR NS ud ERE ATREA M T a x Z z otted crar IMITIAL as TART alEHD SHEEP LIH l toneJ Huto
158. Leo Channel 1 B z HORMAL R Hz Bak Hz dotted crar DUUE UZ ROOMS usREFM STHT Mx Boge F TEIG SETUF FILES AUTOSTR If you desire that both Channel 1 and Channel 2 have a refer 7o ence spectrum assigned at the same time press the N SameREF N key This will assign a spectrum as a reference 3 2 2900B TRAINING MANUAL to ch 1 and ch 2 As new data is analyzed you may switch between ch 1 and ch 2 and view the comparison of the new spectrum to the respective reference spectrum m 26 14 33 s ASIS Y AIS U SCHLE U DFSET H SCHLE H OFSET SYSINFO 1 SPL 1 2258 I6 r K RR RN R RR RR RN RRR RR RN RR RRR R NR RRR R RN RR RRR ANA ir 1 78 al LIHEHRE 26Hz 29k HZ STOP 23 FEB 98 28 13 29 rar RR IIT FILTER 14 z5 IS Hz L 3 s Channel 1 ar z oo r S p E E ee ee a ee ae CLIFF Ph 83 2 Sns 20 05 REM E TACH BH SPEED B B pooru McsTOP HeWHIT McREPT McSTART Ganerer ket Ree GREE 4 Press the SHIFT hardkey then the vsREF P key to return to SHIFT a normal display format PES 28114133 ASIS YARIS U SCHLE U FSET H SCALE H OFSET SYS IMFO SPL 1 2258 I6 r IIT EXF HEHT T DL 1 E 1 LINEAR ZBHz Z2BkHz 439 2 E DIFF Fh 83 2 5n 26 05 TACH BH SPEED B a dotf ed crar SameREF SetREF i Dua STOP 23 FEB 9S 28 13 23 r a dar Ta ad Wel e TEETE EE CEREC chee 0 9 D R 6 FILTER 14 z5 IS Hz Leo i denne 1 ose HORMAL x E E Fs DOOFUS Hc STOP Me WALT hc REPT McSTART Changing from a logarit
159. MANUAL EXIT There are two formats available for the presentation of the waterfall plots In the two dimensional format produced by pressing DRAW 1 D as described in this step the spectra are simply overlaid one at a time without any offsets in the vertical and horizontal directions In the three dimensional format produced by pressing the DRAW 2 D key an offset in both the vertical and horizontal directions is added to each successive spectrum curve pro viding perspective to the view B 1858 HE ZH Z2HkHz T 94 095 2 55 2 z5 H Hz L 3 f z HORMAL AP 70 1 L H Hz INITIAL 590 Hz 16 BkHz A OFF Press the EXIT hardkey to return to the RECALL Menu If you are finished viewing the recalled data press the EXIT hardkey again to return from the RECALL Menu Block Averaging of Autostored Spectra CLEAR RECALL Sequentially stored autostored or non autostored records can be averaged together using the Block Averaging Function summed together using the Block Summation function or the Block Maxi mum function can be applied giving the highest level occurring at the same frequency across all the Nth spectro in the separate autostore records 1 Press the RECALL hardkey to enter the Recall Menu Press the B AVE B key to select the desired records to be averaged 24 EB 1 54 68 WU Fall B AWE E MAS B SUM wsTIME KEEP Channel 1 af 2 HORMAL d A 47 9 DIFF Pns r4 1 5n 18 63 TACH 8 8 SPEED
160. ME DATE TIME SIZE HAME DATE TIME SIZE MEMORY 7 delete mem delete rename The following message Enter new name will appear on the right side of the display HS OCT 16 81 17 A E C D E F G H Hemor Used 26045 Disk Used Memoria Free E Disk Free Enter new name ag HHT MEMORY 5 DATE TIME CATE TIME Enter the new file name ROOM by using the alpha charac ters on the display a4 OCT 186 21 1 Memoria Used TSTS Disk Used Memoria Free ane Disk Free Enter new name ROOM DHTE TIME CATE TIME 1 21 2900B TRAINING MANUAL 5 Press the EXIT key The new file ROOM has replaced the old file name PLANT EXIT B4 OCT 15 23 26 create RECORDS T disk T format Memoria Used ErHrz Disk Used Memory Free 193024 Disk Free ENORI 5 BISE DATE TIME HAME DATE TIME SIZE LOC MEMORY 7 delete rename menm delete rename Deleting a file 1 Press the FILES O key found in either the Main Menu or the System Menu 2 Select the file name ROOM or a desired file to be deleted with the T C or Y K arrow keys Bi OCT 16 23 26 create FECORDS c disk t Format Memoria Used ErHrz sk Used Memory Free 193024 Disk Free HEMORY 5 BISk HAME DATE TIME SIZE HAME DATE TIME SIZE MEMORY delete rename delete rename 3 Press the delete I key Y pd OCT 16 25 42 create RECORDS t disk t Format Memoria Used rz Disk Used Memory Free 193024 Disk Free HEMORY 5 DISK HAME CATE TIME SIZ
161. O RRA Jay oes FILTER 14 75 Hz Leo ELE n 1 ES Dae A DIFF Ph 52 8 Sn 2 42 REM TACH 8 8 SPEED 6 8 5 4 Hz Boa Hz 2H BLC HZ dotted crsr INITIAL dE u SPL Under undef undet Under undef Under The message Push setup to name will appear prompting you to press on the undefined softkeys K P that are 11 1 labeled undef 114 K R ic me oD IS AE Sle ee R a ae SS Yat RT a RR RR R a a NNN RD T KK R O ie R FISH UNITS TU HAME SPL EB BEBA at r ae Side EE Aa qe VE CAS sin DS E RN E cus EENE Moe Nes NA oh say E a E IE A m EXPONMENTIGL 18 Dual LIHEHE ZzEHz z kHz RESET 19 FEB 93 16 13 19 rar A A A D DOE DS COM FILTER 14 75 8 Hz SS o ann 1 hs HORAL r S DIFF Ph 52 2 Sn 2 4z FEM TACH H H SPEED Bg d se RE SE ST A a a a a oa a a RR x IHITIHL under under under under under Under 2 2 2900B TRAINING MANUAL 4 5 EXIT 6 T EXIT Press one of the undefined softkeys to be named The mes sage Enter units name with a flashing cursor will appear on the display Push SHIFT CLEAR to clear old name 19 FEB 16 15 14 H E C D 1 15 A c D LM II MU IIl c Peete at orom oh on m om oho a5 O3 3 3 2 og n m m 9 9 O3 3 O3 o3 nom s sg m 9 9 3 3 c 3 m m ns n m n or on EXPONENTIAL 78 Foo hoa m on p 3 93 S o3 2 AT a m 9 3 2 3 3 2 3 2 3 2 3 1 3 2 3 3 3 n n 0 5 ESL TUS 14 i d A 3 SH EEE a A EE a ee ee Org DIFF Fhz az Sn 7 435 REM TA
162. OE A Ue EON ROCKS UNO C OX N N NR e X A NN NN ces s N FILTER 16 4A A Hz Les r Channel 1 of 1 HORMAL d 23 H E _ 37 8 54 O A E Roe eee ee DIFF Pbs ba p a Ens 7 45 REM TACH a d SPEED a iB Wie Gata tay RA dic AA O A qo ger a A Ge ae as da 5 8 Hz Ban Hz z6 DL HZ OFF IHITIRL 1 0 5I6 GEN IHPUT clock COLOR MLS FILES RESETS Within the filter menu notice that the keys on the top of the measurement display correspond to the full octave and 1 3 octave analysis features The keys on the bottom of the dis play relate to the FFT capabilities of the RTA Keys 100line I thru 800line L are used to select the resolution of the FFT 100 line 200 line 400 line or 800 line Select 800line L to choose 800 line resolution ire z 2 41 29 1lrloct 143o0ct lona short reverse SPL B BREE a A A A ende uf cG uf gen Enge scene ce E ERXF HEHT HL 178 Ingut 1 LINEAR 2bHz 24kHz RESET Bz JAN 9S 23 38 41 79 X Ge E OUO amp O X RR RR RR R K RR RR RR RR RR RR K RR RR RR KR RRR R K R K K RRR R FILTER 16 46 0 Hz Leo Channel 1 of 1 HORMAL d 23 6 L 8 SH ul LL c p c I I C M BIFF Fh S78 Sn 7 45 REN ag TACH H B SPEED B B BH Soi Hz Hl EIEN OFF IHITIHL 1991 1ne 299 1 1ne 466lire S468line FFTZOOM WINDOW BRHSE Bd 7 3 2900B TRAINING MANUAL 4 The next item to establish is the frequency range or analysis baseband This is the maximum frequency of interest for the test item Press BASE Bd O to access the
163. OLOR MLS FILES RESETS 2 Press the 1 10k M high low pass filter option This estab T lishes the high pass filter at 1Hz actual roll off starts at about M 0 8 Hz and the low pass filter at 10 kHz PU use Pane es T ee eee aaa ess SEAL SPL B BEBA aj ILLE LM LL i e e EXF HEHT HL 1 78 Dual LIHEAP 20Hz 25 La RESET 11 FEB 88 01 57 51 TH r A AAN RRA A E R FILTEF id 75 IS Hz Leo y channel 1 of 2 NORMAL E Eee hehehe ehe ene DIFF Ph 52 2 Sn 2 42 REM TACH B B SPEED B a dotted crar ziB 15k SAME aRAHGE 7 6 2900B TRAINING MANUAL EXIT Selecting Units 3 Notice that this selection is now reflected on the right por tion of the measurement display Press EXIT to leave the input menu min 23946 Se pu Za U eB U AUTO FA TEST SPL al lar iat Tas agro Sas ca dd yao ke T EE a gue DA E Se a vhs ele EMI utn EXPOMENTIAL E Ineut 1 LIHEHE 1Hz 16kHz FESET z JAH 3 Ziqri ro A R OR MR RN er ee 2x E R H6 254 A Channel 1 of 1 HORMAL d B d B E B REE R R GPCRS cy EL cue Sainte MESES A NR cane RR he REM TACH 4 46 SPEED Bg d TA Bel HAHA Z O0m 1 Sona 0000 Z A dotted crar IHITIHL A WGT CUST 1 2Bk 29 20 1 16k 29 10 SAME e amp FEHHIGE Now let s establish the measurement units and calibration for the transducer that will be used to measure the vibration The most common transducer used for measuring vibration is an accelerometer For this example we will set our acceleration
164. ON OFF S Time dB SFHH E STAT HIDE CLEAR REDRAW S 6 Press the ON OFF A key to turn on the Statistics mode a SPL EB ria NS SMS KT K S C vr R UR deb D due CAD RT De TNT cd c odes Er S ES rU e UR SEC C NT e A ae C Qe E SEO DOE TE t a i EXPOHE TIAL 1 8 Ineut 1 LINEAR Z26Hz 2BkHz FESET 19 FEB 92 8 11 17 E i pL Say oa A es Bn Wee aba sac saab RUM NR FEH n Ln 14 z5 H Hz 1 221 Ms zBnL uds HS z 19 60 Lmin zB H O E E E CES E O T AE Wee coe N ue ATR 7 NE E a zu z LEG TH a 4 58 29 0 MEAN B d PEL MT TTD 12 H Hz Eod Hz x z H Ln cursor POPCO STO TBL RCL TBL MFG TBL H CHHHHEL 7 Press the N N key to select the desired Ln to be calculated O N 19 CEP QS 225 d9 ON OFF S Time dB SPAN F STAT HIDE CLEAR REDEAL SPL EB BEBA 190 a Slat Saad N cae RR RP R ha E ke N cee iy Rn a O a a ao A EXPOHENTIAL 148 Input 1 LINEAR 28Hz 26kHz STAT RESET 19 FEB 98 BH2 11 17 24 NIN Pc NR A DE FEH n Lr 14 25 0 Hz 1 166 Bn ut zB i 60 Lmin zB ll AH Go aa a E AR ANA A A A a ea et Re Jay a DS OR 2H 26 0 LED ZH gH 29 0 MEAN H E FEM B rH o a dt E g ds A EL oa EDUC XS E a UR UR e OL UBL Teta Le cee RR a Ree TR 5 25 0 ZUHDEF Ae HA x z z 3 A H value POPCEO STO TBL RCL TBL MEG TEL CHHHHEL A Select the trace number 1 6 via the numeric keypad whose parameter value is to be changed a gt gt will appear next to the selected trace number B Press the horizontal keys until the desired Ln value appears The analyzer
165. ONS 64 4 TACH 8 8 SPEED 48 8 Trigger A Enter the desired level using the numeric keypad and press the EXIT hardkey 3 Press the R S key to ARM the analyzer B3 OCT 15 31 62 380 pS 29 sab Hz 426 H 5 EB mia TH BS cos RA A MEE M EXPONENTIAL 18 LIHEHE 2HHz 28k Hz 63 OCT 94 15 38 43 54 O A A A o RY 9 FILTER H 1 E ag Hz Leo TRIG Channel 1 of 2 HORMAL lt d 17 6 B 56 9 ad Pe I a A S PHONS 66 5 al TACH 6 6 SPEED B d H z dotted crar z IMITIAL SLOPE SLOFE MANUAL RE ARM OFF level When triggered the display will change from armed to run and timer will start running The measurement will commence once the triggering criteria have been satisfied 4 Press the RE ARM N key if you wish to have the analyzer reset itself following a triggered autostored sequence This will re arm the trigger ready to autostore following a subse quent event You can toggle this feature on and off by press ing this key repeatedly B3 OCT 15 32 16 B 29 SAH Hz 626 9 5 B mid EXPOHNENTIAL 14 8 Dual LIHEHRE ZElHz zBHkHz STOP B3 OCT 94 15 31 46 FILTER 1 56 Hz Les Channel 1 of 2 HORMAL d Ee 58 4 FH HS 65 9 TACH 8 8 SPEED 4 4 z dotted crar MANUALCRE ARM OFF level EXIT 2900B TRAINING MANUAL 5 Press the EXIT key to return to the Main Menu Note that pressing OFF O in the F TRIG menu also exits you to the Main menu 6 To de activate the trigger f
166. PART QA deae gum eene L AREA 25 8 Hz JHE Hz 1B8 BkHz A ranae a HITEST Job Fart area PretrsP meter SETUP FILES AUTOSTE Normalization of input channels EXIT At this point it is recommended that you phase and amplitude match the input channels 1 and 2 by performing a channel nor malization You can use the optional built in noise generator of your Model 2900B or an external noise generator to do this Please refer to your user manual to perform a channel normal ization This is recommended but not required Within the Intensity display screen one can establish the various acoustic intensity measurement correction parameters These include the ambient barometric pressure temperature and spacer length 1 Press pr t sp L to edit and enter the values for static pres sure in millibars temperature degrees Celsius and the spacer length in millimeters 12 de 21 11 37 POWER INTHSTY QUALITY SPL F UELOC DISPLAY note DETECTE erm B BEBE SH x RRR K RRR RRR K ROO N I EXF HEHT IHL 18 i Dual LIMEHR 25Hz l8kHz i RESET 12 JAW 392 21 18 44 iB FILTER 24 z956 Hz Lora 1 A INTENSITY L d 13 6mm BA TT l EEE bebe jk E EEE N E eo es POW 19 441dBE 61 09002 REM PART AA e AREA 25 8 Hz JHE Hz 1B8 BkHz A ranae a HITEST jab Fart area Pr L Sp meter SETUP FILES HUTO STE 13 8 A Hz 16kHz 21 18 44 Bi3mbar 25 8 C 2 Be Dre N B 25 8 Hz 246 Hz 164 BkHz E H ranae au HITEST 2
167. PL ls 168 K RR ES a aR I Sa UE CGU a A TES LU pe ae eee DL a AL Te R des R So HR Re ex iT e ae RRR UR COUNT MANUAL ACCEPT Dual LINEAR iHz 1BkHz RESET ar JOH 98 01 55 34 BB tet way Ties Da Cen a O AA RR AR TNT HR PEUT di lt Qe A ARARAH a 1 FHULO Fec trun L b 3 11 3 B 17 eh K SpA E r e SOR aor E a DOC TN CE EN da JOE SEIS UE WT i Se AC SEE E ORO i Qu See fuf GE Ro cas oh mb TOF A a Baze Fre usnmnc y QG S AHHH REM TACH 8 8 SPEED 8 8 aa aaa 00m 1 246 5700 E A dotted_crsr INITIAL 1 0 SIG GEN INPUT clock COLOR MLS FILES RESETS 22 From within the UNITS menu press name B so that you can create the label for the response channel accelerometer s vA We will use g s a7 JON 01 56 30 SLOPE SAME R UMITS Hoise F mi cal U cal level SPL aa 106 2242 rc ko AA E eM a see E A A ee o ETA EA COUHT FIBIHLBIL HCCEFT Gual LINEAR iHz 1BkHz RESET 07 JAH 98 01 55 34 esa oec cu ak dale wa dat TN A REO dicc E LESE FREQ Aa ARRAS ESHH Hutao Spectrum D 2 11 3 17 7 GE R N ee Ele ae Se a Sh er eR ey es Ee See ae ee T7 Base Fr euenc y A AHHH REM TACH 8 8 SPEED 8 8 aa aad 00m _ 1 246 8750 E A dotted crar IHITIHL dB el SPL E ETS undef undef under undef 23 Press one of the undef undefined UNITS keys such as W undef K and type in G a7 JON 82 83 00 A E C D E F G H Enter units name G S 100 RA RR K AAA RTE RN E tee R A R ode se A N R RR RA COUNT MARLIAL ACCEPT Dual ERR iHz 18kHz RESET B
168. PUT clock COLOR MLS FILES RESET S Press level H eris 22d 10 SLOPE name SAME E UHITS Hoise F mi cal U cal SPL 3 95588 a Cw 7 yd ooa a a Aut cep e cus cay ES E EXPOHENTIAL 1 8 Dual LIMEHR 26Hz 16kHz STOP 12 JAH 398 26 23 61 TH E wt N RT LM rN E SRS E 001071 DTI O FILTER 24 254 Hz Leo Channel 1 of 2 HORMAL d 161 1 A SH pssst E oie Gay a Say EE Ee rita Genel ht AA o Gea ene E DIFF Fh 91 6 n 30 or Balle TACH Ha SPEED a d dat ted ace x z IHITIHL under under under unde Type in the output level of your calibrator 114 0 dB for the CA250 12 JAH 26 25 36 116 Enter Leue l SPL emi a A e ae EO eB i awe ar Sa SE ee Utes ame ah So 7 072102 EXF HEHT T DL 1 79 Dual LIHEHE 26Hz 16kHz STOF 12 JAH 98 26 23 61 FILTER 24 zoH Hz Lx Channel 1 of Z H d 161 1 DIFF Ph 91 6 5n B B SPEED B a dotted crar TH Se n aon non non SH Se om m m non n on on on REM TACH Ab dia vee URS belts eee INITIAL Press EXIT Channel one is now calibrated To verify calibration make sure that your calibrator is still on and press R S to begin another measurement The level that you read at the cursor location should be the output level that you defined 114 0 dB for the CA250 If not repeat the calibration Press R S to stop the measurement 2900B TRAINING MANUAL 8 Now calibrate the Channel two microphone First remove the channel one microphone from the calibrator and insert CH2 EXIT
169. R O ee a E CHR a N H R 8 R RTE a DORT O A me GE the Se te ca DIFF Fh Za 1 n lt dd REM ec TACH 9 9 SPEED Bg d s z z E dela2s 1 65 ROOMS SIHE FIHK WHITE FULSE DECAT 5 Press EXIT to return to the SYSTEM menu Making the RT60 Measurement RESET R S CLEAR RECALL 9 12 You are now ready to make the RT60 measurement Verify that the speaker and microphone are placed in the desired positions 1 Then press R S to begin the RT60 measurement After the measurement is complete press the RECALL hard key The first spectrum at 0 05 seconds into the measure ment that was captured during the autostore process will be displayed ZH PEE 15 87 19 W Fall B RUE B MAK B SUM wsTIME KEEP Hate SPL B 6500 r LIHEHRE FEPEAT B mi bTIME Dual LIHEAR 26H EH STOP zH FEB 98 13 86 67 54 FILTER 276 446 Hz 5 3 Channel 1 of 2 HORMAL d 65 7 aa KS DIFF Ph 83 3 5n 38 65 DES TACH Ha SPEED a d R Hz Bak Hz s hrec all data ROOMS DELETE H Freu H Hext CURSOR 3 2900B TRAINING MANUAL Press the right arrow hard key until you get to 1 sec Beyond this point you will see the spectrum start to attenuate ZD S 15 89 49 N Eal l E RUE E MAM B SUM zTIME EEEF Hotes SPL 1 9096 TH RR N NNE Wy Sal See RR tc ikke de RT e TTD as oe ua Ge N E d o inal TER CAD ae le GRIS ox LIHEAR FEFEAT 5 gt ASH bT IME r Dual LINEAR ZBHz lWHkHz STOP 7H FEB 98 15 06 07 SH o ee FILTER 26 40 Hz Sri id 1 E a d
170. ROCO UK Wal QC H IRIS SW M o VEO e C I one ECC sc ai ERXF HEHT HL 18 Input 1 LINEAR 2BHz 2AkHz RESET 19 FEB 98 Arix31 19 rer CoN ry do ET N N A Hee Sannin cus e Sah Masaya PEE FILTER 14 75 4 Hz Leo Channel 1 of 1 HORMAL d 24 2 A 36 1 aB r koe dero D EODD Cede cm E Ie E ie dec CROSS A UE ce XC COS Ce T Oe dence c XIUNDON UM BIFF Fh Bd d cn ETE SEL l TACH HLH SPEED B El 25 0 Hz Bae Hz 206 QL HZ datted crar F UPC ROOMS usEPHM STAT Hz Spec F TEIG SE TUE FILES AUTOSTR 2 Press the S Time B key to enter the desired time interval that the data will be taken from the measurement buffer to the Statistics Table 19 FEB 75 95 09 DON lt OFF S Time dB SPAW E STAT HIDE CLEAR REDEAL FEE 07 39 89 ON OFF S Time dB SPAN R STAT SPL A HAHH ad A E EASE oa a EXPOHENTIAL 1 5 Ineut 1 LINEAR Z26Hz 26kHz RESET 19 FEB 38 Bri31 15 TA GTP 26 9 ab Wa N ee Gee cae Ses ate oan T EY en te at R R ee eae 07 an T ee ak cae See Sa a ae 2 25 FILTER 14 25 4 Hz L4 Channel 1 of 1 HORMAL 24 2 36 1 54 Ice E ee ee REN DIFF Fhz 54 5n tare SEHE TACH H H SPEED Bg S H Hz 636 Hz Hz EH Ln cursor POPECE STO TBL RCL TBL MEG TEL H CHHHHEL x 3 Enter the desired interval time in seconds via the numeric EXIT keypad Press the EXIT hardkey 19 FEB Hr 43 438 116 at a z 2H rial r Z L OR MA d 24 2 A 36 1 SH RL Shee imeem SHE C Ge abt awe ate eas R Pane Sa Taek s
171. RR N RR K NR RN RR R LIHEHFE STHGLE 2H EE Dual LIHEHR 2HBHz zBkHz E 388 10 10 64 SH TI ARN OA e e O CTI e X TTC MUST FILTER 14 zh Q Hz Leo de Channel 1 Ut Z Ee e r A Aa id a ed a ae Sects e io DIFF Ph 55 9 Sn 6 85 REM l TACH H B SPEED a a S B Hz Bae Hz 7H BEA dotted crar ROOMS SIHE FIHK WHITE FULSE DELAY The noise generator will deliver a pink noise signal to the speaker amplifier system 18 Press R S Adjust the channel one input gain of the RTA RESET such that the signal is optimized without creating an over R S load condition The best way to do this is to press the down arrow hard key until an overload occurs 23 907 18 14 19 OH OFF OH RUM OFF RUH ATT ATT SPL s LIMEAR SINGLE zB 2690 Dual LIHEHE 28Hz 28k Hz STOP 235 FEB 98 14 13 42 FILTER 14 25 8 Hz Lea Channel 1 af 2 HORMAL Lr A DIFF Ph 2188 1 n 64 77 TACH BH SPEED B a S A Hz Bok Hz dotted crar EDS SIHE FIHE WHITE P LSE DELAY REM 19 Then range up by pressing the up arrow hard key until the overload indicator disappears 23 ba 16 15 16 OH OFF OH RUM OFF RUH lt ATT HTT 1 SPL zt m ag r NA A ANA LIHEHE SIHGLE zu Em Dual LIHEHE 28Hz 24k Hz ETOP ZA FEB 98 16 14 45 r Ln NN AS O E RE OO FILTER 14 z5 IS Hz L 3 ws Channel 1 of 2 oe r D apre NN AR NA NA DIFF Ph 144 1 ene Bd Gl REN E TACH H H SPEED Bg d H Hz Eod Hz z doatted crar ROOMS SIHE FIHEK WHITE PULSE DELAY You may
172. Rr K 267 R M R RR cata es N N FESS EA AE EE Ulus d J i HAm JOB TEST PEM ag l AREA A z ATTE i z range 25 8 H S 14 GkHz E A Sa HITEST Job area Prrtersp meter SETUP FILES AUTOSTR The part would be a subcomponent of the job Again press the various alpha soft keys to create the part name that you wish Then choose EXIT to enter the part name 12 H 38 B BEBE E 7 L Dual LIHEHRE 2BHz l8kHz i RESET 12 JAN 32 21 15 49 iB FILTER 24 z258 Hz L73 l A we THTENSITY 1 d 13 8mm d 139 4 32 54 O R ami See GO SBE 9 GES eee De eae ey te Coke Cup leet Nes F d 2161 BAe pee i JOB TEST FEM i FART AA e AREA 25 8 Hz Sud Hz 18 6kHz E A ESV au HITEST I J K L i H U F 2900B TRAINING MANUAL EXIT EXIT 5 Press area K to enter the name creation field for the area name 12 ded 23 18 14 POWER INTHSTY QUALITY SPL F UELOC DISPLAY note DETECTA B BEBE 1 5 i Dual LIMEHRE 258Hz l8kHz I RESET 12 JAN 33 us on m m nm zz aL m r r4 n rr 18 FILTER 204 256 Hz L73 A we INTENSITY 1 d 13 Bmm i 44 54 K lah Re la aA A Gee glee da AAA ere eae aie T F lJz dE 201 baa JOB TEST REM PART FRONT Alerces I AREA 25 8 Hz JHE Hz 1B8 BkHz A pande a RITEST job rari area pretres meter2 SETUP FILES AUTOSTR 6 The area would be a subcomponent of the part Once again press the various alpha soft keys to create the area name Then choose EXIT to enter the area name I Es PLA L 1 5
173. SMS beam with stinger FFT analyzer Shaker Excitation Functions e Swept sine Highest accuracy excellent signal to noise ratio often used when testing very non linear structures test times are very long e Random Noise Good general purpose excitation best linearized approxi mation for non linear system test times are very short not good for testing systems with backlash such as a gear drive e Chirp Similar to swept sine but faster good signal to noise ratio good for testing noisy systems 11 12 2900B TRAINING MANUAL Attaching Accelerometers e Metal Stud Very secure usable frequency range DC to 20 KHz e Cement Wax Easy to attach amp remove Usable frequency range DC to 15 20 KHz e Magnet Easiest to attach amp remove usable frequency range D C to 5 Khz Test Setup Establishing a Measurement Grid e How many measurements e Need to take enough measurements to be able to resolve the highest order mode of interest e Too many measurements is a waste of time too few measure ments yields little information about the dynamics of the structure Test Setup Determining the Reference Point e When using a shaker the location of the load cell is the ref erence point fixed excitation e When using an impact hammer you can do one of two things 11 13 2900B TRAINING MANUAL impactata single point and move the accelerometer fixed excitation
174. TOSTR 2 Select EXP C to activate the exponential detector C TI 24 15 11 LIN S LIH F BT ExP BT LIH Al TIME SPL EB BEBA SGE i ee a i whe a ee haa prese ata e dede ee ee EXPONENTIAL 8 Dual LIMEHR 26Hz 16kHz RESET 12 JAW 393 13 ch ee ques dad Boe pg edd ara doe sod i dece Se PA EXER FILTER 24 250 Hz Lez MEI n 1 es KOR ae ol TTT DIFF Ph 62 8 zns 7 88 el ae l TACH Ha SPEED B d dotted crar INITIAL 12 14 EXIT SCREEN SYSTEM 2900B TRAINING MANUAL 3 Then press AV TIME H averaging time dd 24 15 11 LIH S LIH R EXP BT ExP ET LIH SPL EB cia TED 233 d Exil d Soc d dox aes edo bola dede doe deb EXPONENTIAL 178 Dual LIMEHR 26Hz 16kHz RESET 12 JAH 3S 19 58 59 EL htedin wana des O FILTER 24 250 Hz Lez a 1 of 2 HORMAL EB eee ee e ee ee ee ah DIFF Ph 62 8 zns 7 88 E I TACH 9 9 SPEED B d z dotted crar IHITIHL 4 Next select 1 8 D sec rd 24 16 63 1 64 1 432 116 144 1 2 1 z SPL EB ma 140 ppt ppp PME EC ERXF HEHT T DL e Dual LIMEHR 26Hz 16kHz RESET 12 JAW 3923 19 58 59 asi K db de ds R vel LIES e OS DE e dL AP UE cS MO des CN VELO UN OC dL CUR cS Ee e s H MT TR C a Sei S R N FILTER 24 254 Hz Leo Channel 1 of Z HORMAL d 35 9 A a 5b A DET SRL CRAS VS RUSSIE axem C at cbe rg TS A A SEE DEP ENT QE BIFF Fh 62 Q cn T He SR I l TACH 9 9 SPEED Bg d s s z dotted crar IHITIHL 4 a 16 Az ed 128 256 12 Press EXIT to return to the MAIN menu then press the SYS
175. TS FILTER CLASS SPL B BeBe A EXPOHEHTIBL 1 8 Dual LIHEHRE 26Hz 26kHz RESET 19 FEB 938 16 65 45 FA eee eee eene FILTER 14 25 8 Hz L Z dd 1 of 2 NORMAL 58 IN X R R ce Ree Ph nz S Sn F 43 REM TACH H B SPEED B B Rac m we a OC a a LLL xn n eee pone IMITIAL I d SIG GEH clock COLOR MLS FILES RESETS 2 23 2900B TRAINING MANUAL 2 Select one of the following analog filters ze ER 18 14 36 Bu 28 U zB L AUTO RA TEST SPL B amaad 290 r KR RRR RR K RR RR RRR NR N RR KR R R NR RR R RN RRR E EXPOHENTIAL 148 Inrut 1 LINEAR 2B8Hz zBkHz RESET 26 FEB 98 1B 13 33 DE rrr FILTER 14 25 A Hz Les Channel 1 of 1 HORMAL 24 4 Ee 359 2 aB r A A Hae ts er E ER URDU dE SIC sae Cou nde a a I aa NRT A Hs CE cde ha a SO e A BIFF Pbs Bd d cn Yara REM TACH a d SPEED 4 6 dotted crar INITIAL SAME eRARIGE A WGT I A Weighting C WGT J C weighting 1 20kHz K Flat response from 1 20kHz 20 20kHz L Flat response from 20 20kHz 1 10kHz M Flat response from 1 10KHz 20 10kHz N Flat response from 20 10kHz The analog filters selected are identified on the right side of the display icy 10 14 36 Bu zo U zi U AUTO FEA TEST 1 SPL EB Be EE ds vici QUEUE QE R TEN IU ur ET TE RETIA CP cue ul OI EP VRBIS O Quy Sua Kok SENSN EON UD QE DR TERN UA FUR ERXF HEHT T DL Input 1 LIHEH RESET 26 FEE H H ree fe aoe ee ae he Gas R Sa a NR R R R SL ie a GR a a Re a a D
176. TYPE 1 e EC 804 TYPE 1 In this chapter we discuss the setup and operation of the sound level meter functions available on the 2800B 2900B in the fol lowing order e Sound level meter with frequency analysis e Wide dynamic range sound level meter no frequency analy sis Sound Level Meter with Frequency Analysis 1 To place the analyzer into the SLM mode press the SYSTEM hardkey then press the SLM A B key 8 1 2900B TRAINING MANUAL 8 2 The display will be configured as shown below s er 14 54 35 MORMAL Lea MIH MAM SEL DISPLAY note DETECTR SPL zB 3968 WE iplc a EE 1 5 aa EXPOHEHTIAL 18 Inrut 1 LINEAR 28Hz 26kHz STOP 11 OCT 94 14 54 69 X aoe vr N aa nos ae e S E pum FILTER Ha G ZD Hz LA Channel 1 af 1 HORMAL d 37 4 a 58 7 SW EE Z Min 5 5 Max A 3 z SLM DATA edat ted IHITIHL SLOW FAST IMPULSE LEG lle iaht SETUP FILES ALT cree OTR The A H keys control the RTA functions of the analyzer and associated setup parameters shown below In the SLM operating mode these keys function the same as in the RTA operating mode described in the Main Menu section of this manual Refer to this section if you are unfamiliar with the operations of these keys dot t Weight SETUP FILES The I M keys control the SLM functions of the analyzer and associated setup parameters i ire 14 54 35 HORMBHL EL DISPLAY note DETECTR 28 3988 a L HEHR 2BHz7 26k Hz STOP OCT 94
177. To view the Leq during the runtime press Leq B You will notice the Leq spectrum on the left and the overall summed Leq value on the right of the display 13 FEE 12 43 05 WORMAL Ley HIH MBA SEL DISPLAY note DETECTA LEG SPL 11 1958 LJ gt EXPONENTIAL Dual H WEIGHT ETOP 19 FEB 98 12 41 25 Bare 6c A FILTER 14 25 6 Hz Leo ve Channel 1 UE Z LEQ E RE DIFF PR hGT sm REM oa TACH Ha SPEED Bg d H Hz 55d Hz A dotted crar FOFCO ROOMS usEPH STAT Hx Been E TEIG SETUP FILES AUTOSTR To view the MIN during the runtime press MIN C You will notice the MIN spectrum on the left This is a spectrum showing the minimum value that occurred in each 1 3 octave bin during the time of the test The overall MIN value on the right of the display is the summation of these MIN bands 19 FEE 12 44 15 WORMAL Lea d IH HAR SEL DISPLAY nate DETECTE L 11 1958 140 LES d Canes Sheer aa BATE DE mT al ial NU Gen MESSA TNNT EA GET uty abt sia E UE ATE Tan Kit Bp AE CA ral Set RETE ORO Ap Gun Gh eee oe EXPOHEHT AL 1 al A IGHT OF 13 B 38 12 41 25 ai Was wood Wo do OO RS NU ee we OC ORO CAE ie Gon co Os CR ONE ee acd CCS CUN al af OD GEE ON ane R e OU A FILTER 14 75 8 Hz Leo Channel 1 of 2 MINIMUMS d 36 7 B 34 4 cc DIFF Ph 26T 5nz REN a TACH HLH SPEED a El z z A z H datted crar F UPC ROOMS usEPM STAT Mx Spec F TEIG SETUF FILES AUTOSTR To view the MAX during the runtime press MAX D You will
178. Training Manual Larson Davis Table of Contents Chapterl Introduction to LD Real Time Analyzers RTAS 1 1 AIN ZE TT ENTRO gee 1 2 AA A aml Macedo aides 1 4 Selecting a display Parameter icin dd 1 4 Display wele Nne aussi di 1 5 Annotation of a Measurement sse eee eee eee 1 9 Seleccion OL Det E ESA TUE 1 10 Special Meastirements incio 1 12 EAS RT ia 1 12 Storage and Recall of instrument setups esse eee eee eee eee 1 15 Ele Operations aislada 1 18 AUOST DM ida 1 27 Recalling an Autostore eresiaren 1 29 Waterfall display of Autostored Records 1 31 Block Averaging of Autostored Spectra eee eee 1 33 Chaptpr2 yStem Melisa aaa ER HIDE 2 1 Operation Modest dt dados 2 1 Selection of Units and Calibration sese sese eee ee 2 2 Calibration based on a Reference Signal eee 2 4 Calibration based on a Transducer Sensitivity Value 2 5 Selection of Filter Type Octave Fractional Octave and FFT 2 5 VO RST Te Sida 2 10 Control of the DC output port sss sse eee eee 2 11 I POT COMO AAA A baie a de 2 12 Key A and Key B controls ee eite deo dee iet deus 2 12 IDC CDE CCOBU OL o diro detiene uat eolica adi 2 13 Operation of the Noise and Signal Generator Opt 10 amp Opt 11 2 14 2900 TRAINING MANUAL Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Option L 8 NOISE General nt a 2 14 Option 11 Sienal Generator ul 2 15 SINE T cccc
179. UTOSTR 11 28s 11 45 13 A SPECT C SPECT amp s FEF COHER TIME DISPLAY note DETECTE Hotel DOUBLE HIT LEF eB ELEME EQ COUNT STHGLE 4 DIRECT LINEAR 1 3 2kHz RESET 11 SEP 22 11 14 23 EM ies A FREQ AA ARARHS ESHH Huta S5rectrum D 1 47 1 n B1 Viu bee E R A a E al a OR N fa te carvan G nd Sut qu N ER TR Base Freauenc y TACH 8 8 SPEED 4 6 UU 5 solid crar MIS HLTEREH EBLlIHOFHM PE T TRIG SETUP FILES AUTOSTR Impact Hammers Off Axis Hits e Off axis his will result in reduced energy in the intended direction This causes errors in the measurement This may excite modes resonances that would not normally be excited The actual force that the test item experiences is less than the measured force that the load cell see The amplitude of the frequency response function will be too high 2900B TRAINING MANUAL Impact Hammers Averaging e Averaging a number of measurements together will improve the quality of the measurement e 4 to 20 averages should be sufficient e Ifthe measurement does not improve by increasing the num ber of averages something is wrong Exponential Windowing e Exponential windowing prevents spectral leakage e Leakage causes measurement errors particularly in lightly damped structures e The response signal is multiplied times the decaying expo nential curve window to insure that there is no amplitude at the end of the measurement e The exponential wi
180. a Garrat es a Sate eats aca a pce Nasa bates santa Suse oe PIFF Fhz 2d FI x REM E ACH H H SPEED B d H Hz datted crar DUUE UZ Dia WET BWwHORM If you are making a measurement that requires a special weight ing curve you may create your own by pressing this key and en tering the desired weighting values For a detailed explanation of User curves see Chapter 10 of the operations manual a 23130141 1 41 1 3 SUM SETUSER nate Multi Hote SPL Z 5588 38 d 64 podere oath dios deka RATE qi AET e dus er 80 Magan ais at RC T des san 20 TR 57 L RZ a TR eh NRT avr R ME NTR cas d EXPOHENTIAL 1 8 Dual LINEAR zBHz zkbBkHz STOP 23 FEB 98 23 22 44 Tar uH RE a RE es ee is eS eh ee he Sh ie ite eS FILTER 14 25 4 Hz Les Channel amp of 2 HORMAL d a 4 7 Sa be ha ee ca ee ed rele 8 es cas oot DIFF Ph 24 7 lt ms 22 22 REPE E TACH 0 0 SPEED A dl Hd Hz datted crear DUUE UZ M SUM BEWHORH This key permits the analyzer to simultaneously display multiple channels The maximum number of channels displayed will be determined by the number of input channels configured in your analyzer i e if you analyzer is configured with four channels you may select up to four channels to be displayed simultaneous ly To return to single channel display you press the Multi H key again EX 23 33 74 1 51 1 3 SUM SETUSER nate Hate SPL 2 2506 98 E ATE 6 REO MOI ERAS EMEN RE TT ETE TIE C I RE R IC IE EXPOHENTIAL
181. aa acc FILTER 14 75 8 Hz Leo Auto SrEectrum d 24 3 B 39 1 AS A A o vict hut REM a l TACH BH SPEED B B 5 8 Hz Bou Hz zB BEHz L dotted crar DOOFLS User SETUPS EDIT eject init 8 Press the EXIT hardkey to return from the Print Menu EXIT 6 3 2900B TRAINING MANUAL 6 4 Vibration Measurements The following is a procedure for setting up the Models 2800B and 2900B Real Time Analyzer s RTA s for basic vibration measurements In this exercise we will use the FFT narrow band analysis feature of the analyzer We will setup the RTA for a single channel measurement with the understanding that dual channel vibration measurement using the Model 2900B is a simple extension Cross channel measurements such as cross spectra transfer functions coherence functions etc will not be addressed in this section Note that the menu structures of the 2800B and 2900B are slightly different For this training exercise the procedure and screens relate to the Model 2900B The 2800B layout is similar enough that this should not provide much difficulty to the user Creating a Measurement File 1 Before starting any test itis always a good idea to establish a new measurement file Data records that are measured will be stored in this measurement file After turning on the power to your RTA press FILES O B3 MAR 1 19 50 NORMAL Les MIN MAX SEL DISPLAY note DETECTR l SPL EEEE an s Huh A A tg ace etinm A og atas
182. abeled sendx The next three could be labeled receivedx Record number 7 could be labeled backgnd ZB FEB 13 18 85 crea Memory Used Disk Used Le 24456 Memory Free 695868 Disk Free Hate MEMO S gt RECORDS 7 rename lete x You should now have 3 source room measurements 3 receiving room measurements with noise and one background noise mea surement in the receiving room Now use the block averaging capabilities of the RTA to compute an averaged source room measurement and an averaged receiving room measurement 9 To average them together first press the RECALL hardkey The last receiving room measurement that you acquired will be on the display You can display the 5 other measurements by pressing the left arrow key hardkey 10 Now let s average the source room measurements together Normal 1 thorough 3 Press B AVG B Hote SPL zt m LIMEHR SINGLE zB m Dual LIHEHE 28Hz 24k Hz 3 FEB 98 18 14 48 E Hz Les ve Channel 1 of 2 ee DIFF Ph 21i B 1 SpE 64 61 TACH H H SPEED a d recall data E 18 42 26 W Fall E MA E SUM KEEP REM E ze El Hz ROOMS DELETE 11 In the field on the top right side of the display type in 0001 0003 This tells the 2900B that you want to average the 3 source room spectra 23 FEB 16 43 47 Last H 168 KR RR NR RR R R RR RRR RR E 1 HUERHGE Hogi mus LINEAR SIMGLE Dual IH A Les ve Channel 1 of 2 NORMAL DIFF Ph 1048 1
183. ae ey FILTER 77 SAR Hz Les i Channel 1 of 2 HORMAL i d A 46 5 54 a da E E E N E SG E E E E E laa AAA PHONS 13 a LOC l TACH H H SPEED B a i A S recall data Pre Hex reca INITIAL DELETE H F A Hest 11 To turn off the Autostore function press the OFF A key in the AUTOSTOR menu The byTIME message on the left side of the display will go away 5 a mita endzaetor nara 84 OCT 47 48 17 V OFF byTIME delt dst t I i SPL B ABBA 2B Bode Se zoo x ox mu ee x o9 O3 xe Y de m doce m CELOS ee ee Yom md Veces ES D Ba a un e EXPONENTIAL 1 A BTIME Gual LINEAR 26H 26k Hz i RESET 64 OCT 94 07546 12 B xe Donne Ia stro ee et enr sae X RP Gey ESL S81 inte PV cm uh ve eet ur ms ur Gap Sept EN B one LEV Ep CEN ied dis ine Ua Snr Aa ae xD Ve FILTER H 1 ME Hz L i Channel i of 2 HORMAL i d A 34 7 28 som xoxo wo kom x xo OEORON R O3 Re ER O EORON WO X x O PHONS Sd 3 LOC gi TACH 4 8 SPEED 4 4 E E z E z dotted crsr INITIAL ESTACH TACHSET F TRIG ILES The routine just explained is for a manual start of the Autostore function The analyzer has the capability to begin the Autostore function automatically by setting a frequency trigger explained earlier in this manual After setting the frequency trigger and activating the Autostore feature press the R S hardkey to place the analyzer in the ARM mode Upon satisfaction of the trigger criteria the analyzer will begin the Autostore a
184. ae sine AE ee imi II I L TRCH 4 8 SPEED 4 8 DOOFL 7 usen SETUPS EDIT R eject CE is 6 optional Press the LOGO B key to create a user defined V logo that will be printed as a heading on top of each printout F from the analyzer The default logo is Larsone Davis e 23148155 screen table all uideo TYFE List SPL B piana at EE E ON ditor pie ae Sen cms os ics qoom clar E dide e imd dirus A np A ck ERXF HEHT HL 1 8 Dual LIHEHR 2bHz 2HkHz RESET 16 FEB 98 23 47 33 TH EREE fra i cee ste E ee escis sc pein ee ETT T FILTER 14 zh Hz Lera Auto SrEectrum d 24 3 B 39 1 o SED l TACH H B SPEED HL 25 56 Hz Bou Hz 20 BEAZ datted crsr DUUE US User SETUPS EDIT eject init 7 Press one of the following keys to print a desired data record screen A Prints the display presently on the LCD screen of the analyzer table B Prints the data presently on the display in a tabular form all C Prints both the data presently on the LCD screen and a data table representing the data being displayed List H Prints the data table to the screen instead of a printer 6 2 2900B TRAINING MANUAL video E Printsa black and white printout of the display shown on the op tional Model DVX001 Color Video Adaptor 16 FEB 23 48 55 screen table all video 7 Logo 8 TWPE List dies Gow ele ED 1 SPL B BREE at T IQ D I LL X a E EXF HEHT T DL 1 79 Dual LIHEHRE 2 amp 8Hz zBkHz RESET 16 FEB 98 23 47 33 TH Re LI A A a
185. aj r KET RR N N O E E aw EN N tis wo d ae CES ONU Get RA AA N E EXPOHENTIAL 18 bTIME Dual LINEAR 26Hz 26k Hz i STOP zd FEB 93 26 16 13 re E A O NA EA hme OS tah ee sup AN AO FILTER 14 75 Hz a N SHE 1 E HURNAL A DIFF Ph 65 6 S5n 5 66 TACH HG SPEED ALG hrec all data Zoe DOOFUS 1 34 EXIT EXIT 2900B TRAINING MANUAL Press the numeric keys and horizontal arrow keys to enter the range of record numbers of the autostored records to be summed together Press the EXIT hard key In the third line down on the right hand side of the display the word SUMMED will appear indicating that this autostored record is a summed record E Ba d65 57 lh Fall E AWE E MA B SUM 1sTIME KEEP Hate SFL SUMMED EXPOMENTIAL Dual LIHEHFE zHuHz 2 kHz STOP zd FEB 98 26 16 10 FILTER 14 25 6 Hz L Z Channel 1 of Z HORMAL d 37 9 H Ez DIFF Ph 73 7 Sns 18 35 TACH 6 8 SPEED B a H Hz Bak Hz hrec all data DUUE UZ DELETE H Freu H Hext Press the B MAX C key to apply the Block Maximum func tion EE 1 54 68 U Fall BE HUE B MAK B SUM wsTIME KEEP Hote SPL 5 ARE ai EXPOMENTIAL 18 bT IME Dual LIHEHE z 6Hz kHz STOP 24 FEB 22 18 44 65 re FILTER 77 SHE Hz Les id 1 ee A TAL r s DIFF PA 74 1 Sn 10 63 REM TACH 4 8 SPEED B El E z z A brec all data DUUE UZ DELETE H Freu HB Hext The message MAXIMUM 0001 0002 will appear on the upper right side of the display 25
186. al memory of the analyzer format MEMORY delete rename men delete rename 5 Press the EXIT key to return from the analyzer menu EXIT Autostore by time OW 2900B TRAINING MANUAL Before beginning an autostore operation you should select a data file in which you want the autostore data record to be stored To select the desired file refer to the previous section titled FILE operation 1 Press the AUTOSTR P key found in the Main Menu B3 c 15 63 64 HORMBHL Lea MIH MBPS SEL DISPLAY note DETECTA i SPL 1 7458 TH xui deum o A curas lut A A A a aes LY arde o a A EE EXPONENTIAL 18 Dual LIHEBR 2B8Hz 2zBkHz STOP AS OCT 94 14 35 65 sa tie side A ee eRe me age ce sae ee ey ee ee eke he Gate a ee ay ac oh ap et ae v FILTER 1 NE Hz Leo Channel 1 of 2 HORMAL i d 15 7 A 50 6 GA 2 bh HI DEBIDO PHOHS T3 1 TACH 6 6 SPEED B amp z z hdo Cre INITIAL STAT Mx BERE F TEIG SETUP FILES B TOSTR 2 Press the byTIME B key A bTIME indicator will appear on the middle left side of the display This indicates that the Autostore by time is activated a4 po ar d 1r OFF ESTIME delta endstor nate SPL B aaa in RP LLLI LLOSLILLSLCDLOLOLOLOLDLDC EXPONENTIAL 1 A KTL HE Dual LIHEAR 2BHz ZBkHz i RESET 64 OCT 94 Bv 48 12 ra Leda a a E A a a FILTER H 1 ME Hz L i Channel 1 af z HORMAL d A 34 7 2B X Ee ae a AME AR A ie a Rb AE APA Re E a a A PHOMS Sd
187. also need to adjust the output level of the ampli fier speaker in order to insure that all of the frequencies of interest are being excited equally The spectrum displayed on the RTA should be fairly flat within this frequency range The output level of the speaker amplifier should also be loud enough such that there is a significant difference between the background ambient level and the excited level for each frequency of interest in both rooms Leave the noise generator on 9 26 2900B TRAINING MANUAL Making Airborne Sound Transmission Loss Measurements RESET R S STORE RESET R S You are now ready to make a measurement in the source room Verify that your speaker and microphone are both located in appropriate locations within the source room 1 Once the desired output level and input gain have been achieved press R S to begin the 20 second measurement 23 568 16 15 16 OH OFF OH RUM OFF RUH lt ATT HTT SPL 20 0000 a X dat E O A RN E caus LIHEAR SIMGLE 2A 9002 Dual LIHEBRE zBHz z kHz STOP 24 FEB 98 18 14 48 r A AA FILTER 14 75 8 Hz Les Channel 1 of 2 HORMAL d S A 23 6 N RCR TE A NNT E cee REAT Er R E DIFF Ps 199 1 5n G4 Gl BEN E TACH 4 8 SPEED B d R Hz Eod Hz D dotted crar ROOMS SIHE FIHEK WHITE PUL Z DELAY Upon completion of the measurement press the STORE hardkey to save the record into the ROOMS file E 16 15 16 DN OFF OM RUM OFF RUH amp HTT HTT SPL SEG
188. analyzer 2 28 640X350 B 640X480 C 800X600 D SINGLE I DUAL J QUAD K LCD L 2900B TRAINING MANUAL 1 Press the COLOR M key 1 65 16 88 17 Chanls SLM H STANDRE CROSS INTENSY UNITS FILTER CLASS SPL A Em at r ub a wah A A A O ON cute CD ae EXPOHENTIGL 18 Dual LINEAR ZzBHz zBkHz RESET 19 FEB 98 16 03 45 TH r fic SO e WEG we a ae ates NN NR R E A AER A E N R RR N N o ee ae FILTER 14 z M Hz SS a Channel 1 E Z ae r 56 vo iv ri eie KRE R da A rta E Meek dd e a di A DIFF Ph 52 8 Sn R 2 43 PE TACH 9 09 SPEED AA z5 H8 E datted crar IHITIHL I 0 316 GEM IHPLIT ML S FILES RESETS 2 Press one of the following keys to select the proper resolu tion of the monitor being used m 195 53 zT OFF 640x350 640450 506x606 SFL B Ellie 140 r SP RN Re ai N ata ad A a Ra Hat A A a tes Hay Me deel A dk RH a a se R NN EXPOHENTIAL 1 Dual LIHEHE 26Hz 16kHz BESET 7H FEB 982 16 4r 46 asi r A A E A A A E ce DD CAD HELD cs FILTER 14 z M Hz SS ve Channel 1 S Z POR DAL r eB a ai dao ues ees aati dota gene RRA DIFF Ph 65 3 Sn 6 85 REM a l TACH H H SPEED B E S z L dotted crsr INITIAL SIHGLE CUAL Bali Bp LCD For EGA Monitors For VGA Monitors For Super VGA Monitors 3 Press one of the following Keys to select the number of data display windows to appear on the monitor m 10 33 21 OFF 640x356 640450 506x606 SFL B BeBe 109 CE EXPOHEHTIBL 1 Dual LINEAR 28Hz 18kHz R
189. ashes FREQ AA HARAH H4HH Channel 1 of 1 HORMAL d 95 2 Yl H ED ITI N O RR N N NR RR KN N RR RIN NR NN NR RR N NN RR R T N Loc TACH BH 5PEED B B dotted crsr FILES 4 The first item that you need to concern yourself with is the Q scaling of the tachometer signal as it enters the TACH A INPUT of the 2900 The tach signal enters the 2900 with units of frequency cycles or pulses per second Since you would prefer to view the tach signal in units of RPM cycles per minute you need to apply a scale factor multiplier of 60 to the signal 60 x cycles sec cycles min Press t scale A to enter the tachometer scaling entry field 15 OCT 21 47 42 t scale srar t amin t amax t inPut X cal SLOPE x nua o EM al pi haa es dod ME qiie AP dad t Bizec STORE SLOPE Tach input Jack B dia l ST RR RN A Ep RT el RKR R Re Whe ac R K lee Gee A PRE a R UR DES RR ar D SE EXPONENTIAL 1 64 bTACH TIneut 1 LINERE 1Hz 1 kHz RESET 15 OCT 94 28 11 27 44 a O A A A ae RA A A AA ee A 90 UO M FREQ Ae AHAHAH H4HH Channel 1 of 1 HORMAL d 95 2 z 71 0 A anc TACH 6 6 SPEED B BB maa Z nM 1 Sana dotted crar IHITIHL amp scale s sran s amin z amax RADAR RADAR m 5 Type in the scale factor of 60 as 6 000 E 01 15 D 21 42 38 TACHO SCALE PE p a idem ie ap ee mec a we KKR TES ts a ae a AE A ee E R ee IN ee Ks ee N H Ne N EXPONENTIAL 164 bTACH Ineut 1 LIHEHF iHz 1lHBkHz RESET 15 OCT
190. asurement decays to zero at about 16 7 of the measurement duration 10 Press EXP 4 G 12 OCT 13 44 38 RECT HANHING FLAT ZEROPAD IMPACT EXP 2 EXP 6 SPL A eaa ET p PL PTT LITE ERF HEHT HL 18 ua LINEAR 26Hz 26kHz RESET 12 OCT 94 13 43 27 ro 9 NNN X RR RRR A A FREQ Ae AARAHZ HSHH Auto SrEectrum D 1 13 3 E i B E MC a MUR e Baze Fresuenc y Ae BRB LUE ao TACH 4 8 SPEED 4 4 aa BOB 00m 1 1248 3750 E A dotted crsr INITIAL 11 After selecting the desired exponential window leave the FILTER menu by choosing EXIT Then press INPUT K within the SYSTEM menu e pi dz 04 Chanls SLM A STANDED CROSS INTENSY UNITS FILTER CLASS SPL EB BEBA 99 L EXPONENTIAL 14 8 Dual LIMEHR 2BHz 26k Hz RESET r JAH 92 61 39 28 IHH FILTER 14 25 8 Hz Les ESI 1 aS aoa A DIFF Ph 52 8 Sn 2 4z SEM ae TACH Ha SPEED B d Po poe Hz B Ak Az dotted crar IHITIHL 1 0 516 GEH clock COLOR MLS FILES RESET S 11 19 2900B TRAINING MANUAL CH2 EXIT EXIT 11 20 12 Next select a high and low pass filter typically in a modal test one would choose 1 10K M Choose 1 10K M press CH2 hardkey and repeat step 12 ui 1152117 Bu 29 U 268 U AUTO RH TEST SPL B amaad EE KLAR EA M Nc A X D K URN UR m oe OTRAS TO R NORD we aes IR ROUES S D RA EXPOHENTIAL 1 B Dual LINEAR iHz iBkHz RESET Br JAN 98 61 51 68 TE Bree R cates ua NY ee ie oa a AS OE cn AA fae Hoy aun O A ee ae
191. asurement errors Measurement Considerations e Acoustic Intensity measurements can be performed using FFT narrowband or octave bands Measurement should be made in real time e Acoustic Intensity is measured by spatial averaging Spatial averaging is achieved by either taking measurements at a number of fixed points or by scanning the probe about a sur face The Acoustic Intensity for the area tested is the average of the fixed point measurements or the value determined during the scan e The Acoustic Intensity measurements are done across a mea surement surface The standard measurement surfaces are Parallel piped or box 12 10 2900B TRAINING MANUAL Hemispherical Conformal Measurement Techniques 1 Select the spatial averaging technique fixed point or scan 2 Establish a measurement grid 3 Measure the surface area in square meters 4 Divide the measurement surface rectangle or sphere into components and subcomponents 5 Measure the ambient pressure and temperature 6 Select the proper spacer and microphones This is deter mined by the frequency range of interest Fixed Point or Scanning e The fixed point method is preferred if you wish to generate detailed graphics such as contour maps Although you could scan within a small grid 12 11 2900B TRAINING MANUAL e The fixed point method is more repeatable e The fixed point method requires a longer setup time e The scanning me
192. at anytime to one of these user defined Setups Booting directly to a user defined setup If you desire to boot the analyzer directly to one of the user defined setups instead of the default setup assigned by the fac tory perform the following 2900B TRAINING MANUAL File Operations 1 Press the Setup N key 2 Press the gt BOOT F key 03 OCT 15 48 47 name uus R SETUP STORE note i SPL 14 5566 TH Tu EXPONENTIAL A Dual LIHEHR 2AHz 26k Hz l STOP 63 OCT 94 15 38 42 54 a A FETTE ux FILTER H 1 ME Hz LA cou 1 of 2 ES E zn MERE LEERLO PHONS 62 3 Cor ok TACH 6 6 SPEED B dotted crar 54 Hz Skew Hz A Hlc Hz IHITIHL DEFAULT HOISE Under under undet undet under under 3 Press one of the previously defined softkeys J P which represents the setup to be activated upon boot up of the ana lyzer You may reset all of the user defined setups to assign a new group of setups To do this perform the following 1 Press the R SETUP D key This will clear all of the defined softkeys J P and bring them back to an undefined state H3 OCT 15 48 47 name R SETUP STORE gt B00T note A ED I 14 5568 SPL ra K a E Ae a a ae ee ae a Tae in Oc EXPOHWEWT IAL ra Dual LIHEHR 2AHz 26k Hz l STOP 63 OCT 94 15 38 42 54 O a 6 E R a 7 a EI i a oe RY cn TET ux FILTER H 1 ME Hz LA Channel 1 of 2 HORMAL i g s B 66 2 z0 l AA A EL PHONES 62 2 ash m TACH H a SP
193. ate abe MT ke TK ee ior da R eae Sine 197 he ah vane Garcia 167 RT ant T Se ae E Cane 787 ee DIFF Fh Bd d n Years REM TACH 9 9 SPEED Bg d 2 8 Hz B36 Hz zHB HlkHz E A Ln cursor F FCU 10 1 2900B TRAINING MANUAL 4 Press the dB SPAN C key to set the measurement range The present range is indicated on the lower right side of the display Note that statistics must be off HIDE CLEAR REDRAW T 1 0 T m rm Re Gl G ted l3 1 0 cC A cC TH T Ln S Im a T Ln 0 LT Al Ln TI 125 RR MR AA O RW aa Oe ob GEA ie SPL 29 7158 190 h N Se ac A C OE Ge e UR R O R RT A A R LR eR R R R R ae a N N T a ee EXPOHENTIAL 148 Input 1 LINEAR 28Hz 26kHz RECALL 19 FEB 98 08 39 04 24 Kr R T R R A NN RAR O RO FILTER 14 25 8 Hz Les Channel 1 of 1 HORMAL 37 4 A 49 1 AH D ARR du Je dee a ea a A A A e A a E se A Qa ea R CIFF Fh 65 4 5n 7 68 sai TACH H H SPEED B d 5 60 Hz 636 Hz zH HkHz E A tbl 26 148 POPCO STO TBL RCL TBL MEG TEL H CHHHHEL 5 Press the horizontal keys to move the 120dB range to encom CURSOR pass the desired range of input values for the measurement to be made After you have made the range selection press the CURSOR hardkey to re assign the control of the cursor to the horizontal keys Repeated presses will toggle between on and off The STAT indicator will appear on the left side of the display indicating that the STAT mode has been activated al SS 175 Z2
194. ating that the trace has been hidden F ris SS 455 97 ON OFF S Time dB SPFHH E STAT HIDE CLEAR REDRAW 11 6868 L 1 5 HEAR Z2BHz 24k Hz FEB 95 83 33 n Hz 4 SPL IBA ce ee A a E ee ee er e EXPOHENTIA LE n BE Fre Lmax 16 Yes Lmin 3n 2H r o LEG TZ 4 56 67 0 MEAN bo ra ag H N Den OUT pcnc e Pa 62 0 STDEL a 22 0 UNDER az Ln cursor CHHHHEL zH HkHz E A B38 Hz F FC STO TBL RCL TBEL MEG TBL MAW To un hide a trace select the trace with the asterisk next to it and press the HIDE F key The will disappear and the hid den trace will re appear Storing the Ln Trace Prior to storing an Ln trace it is recommended that a descriptive note be attached to the trace for future reference See Annota tion of a Measurement in Chapter 1 1 Press the STORE hardkey to store the data associated with amp the statistics parameter table presently displayed The mes STORE sage STORE Ln Trace N will appear on the upper right side of the display 19 FEB Bs i4r 13 ON OFF S Time dE SPAN R STHT EL HE REDRAW jo stis o RAS CL NO Rd n STORE Ln Trace SPL 11 50006 SP ll e X e e o foo roo ko ro ko koh ono m m n m om non non on on EXF HEHT T DL 1 Input 1 LINEAR ZBHz 2BkHz 19 FEB 98 a q A E A CS n Ln Hz 1 186 Fre Lmax 4 4 21 r amp r Lain 38 3 CAC n nr TAI LEG 2 5 red 280 60 MEAN 63 d 20 STDEU 9 6 B YA Ez amp 36 520 XUHDEFE i Ln cursor POPCO H CHANNEL x This s
195. ature activated on the analyzer See the section Autostore by Time To recall an Autostored file you may either press the FILES O key or by pressing the RECALL hardkey To recall a file with the FILES O key refer to Recalling a previously stored record in Chapter 1 To recall a stored Autostore file with the RECALL hardkey 1 29 2900B TRAINING MANUAL 1 CLEAR RECALL 2 N 3 4 S C Press the RECALL hardkey to recall the Autostore measure ment The recalled record number is identified on the upper right side of the display ud et 23 95 44 W Fall B HUE wsTIME Becpeeeeee ec gessi ES xe M s tL MR ENDE lt RECALL By Time 1 SPL B 1868 EXPONENT L HL 1 8 Dual LIHEHR ZlHz zBHkHz STOP 64 OCT 94 DSS AGZA FILTER 1 oH Hz LYS Channel 1 of 2 HORMAL g A 46 8 PHOMS 57 8 TACH 6 6 SPEED 4 4 z B S recall data IHITIHL DELETE H Freus H Hext recall Press the A Prev N or A Next O to scroll through the autostored records until the desired record is displayed 2561 Fa us Ed OCT z35 58 4d4 W Fall E AVE TIME KEEP 118 a A A NO A XE cee ols RR Ah inn Sensi E EECHLL By Time 1 i Hate TEST 1 i SPL B 1668 2B C O O M EXPOWEWT IAL 1 A ETIME Dual LIHEHR 2AHz 26k Hz i STOP 64 OCT 94 DSS 965 25 ra E Se ae oe kt NR a ec we a a ANA ae Es en ed FILTER H 1 ME Hz L 3 Channel 1 of 2 HORNBL g A 46 8 28 uc Pc A x AR E RR TA PHONS Sy LOC gi l TACH 6 6 SP
196. baseband options PEN ee E ages pet ailla naos SPL a aad 9H T EXPOHENTIAL 148 Input 1 LINEAR 2BHz 26kHz RESET 62 JAH 98 23 35 41 DE FOR Romo moa d s m 9 3 9 2 9 3 3 9 9 9 opos m m o og o sos n o 9 n n pons mom no woyosson sm on n on FILTER 16 40 80 Hz Les Channel 1 of 1 HORMAL 3 8 B 37 5 54 KRN NN RR RN N SA a A ee N RN N N BIFF Fhz bes 5n zd REM TACH 8 80 SPEED 4 4 cL eee eee eee ER Tee Ce ee ee ee ee ee ee ee ee I zo Hz amp 3H Hz f zu Dk HZ FF INITIAL 1Baline 2Bb6line Bbline Saline FFTZDOM npo snt Within the baseband menu you will be prompted in the upper right hand corner of the screen to select UPPER BAND EDGE frequency Press 2 5kHz D aguero me sae ar EB SPL B ABBE J6 rr EXPOHWEWT IAL 18 Ineut 1 LINEAR 2B8Hz 2BkHz RESET 18 MAR 94 15 18 18 re Rd NR R RR N R oR BU Ee A A a e A E A e E cR E E IR OC JR n FREQ HA ARRAHZ HSHH Channel 1 of 1 NORMAL d 3 2 pa Pe a o TREH B a PEED B a lii ZH dotted crar UIEi The frequency scale on the horizontal axis will immediately change to reflect this selection ae aan z 2 41 29 1lrloct 1 Zoct lona short reverse SFL B Bad Bl te eee eee eee EXPOHEHTIBL 178 Inrut 1 LINEAR zBHz 2 kHz RESET 2 JAH 98 23 22 41 rar NO Glee E A O Bp TRR A LO a a EEN G3 FS QUIE MEE A E a AA dar v EP JES AB Re al FILTER 16 46 0 Hz Les Channel 1 af 1 HORMAL lt d 73 8 T 8 58 CLTC TTT CIFF Fh 52 8 zn
197. be stored 1 Press FILES O to enter the file menu I 21 83 42 Chanls SLM H STHHDRD CROSS IHTEHSyY UNITS FILTER CLASS SPL 2 8168 146 fac Seo yy Soy WEA ie A AAN A A ik EXF HEHT T DL 1 78 Dual LIHEHE 26Hz 16kHz STOF 12 JAH 98 26 45 61 asi TTC ai ah sia ad bibs eter Samy Ma ha LUDERE EN RET FILTER 24 z756 Hz Lera Channel 1 of 2 HORMAL d 114 8 H ed 5b 4 xw oxcE x xoxo wo ox AMEDEO ov xoxo EE o oo oo o X Y X XX xoxo X a ae X BIFF Fhz1B8Hl amp n TZ He Bel se TACH 4 46 SPEED a d z z s added creer IHITIHL 1 0 SIG GEH INPUT clock COLOR MLS CCFILES E SRESETS 12 19 2900B TRAINING MANUAL 2 Next press create A Q 12 JAN 21 06 03 Create RECORDS 1 dick E fornat Memory Used 5 Disk Used A J J D D A Hemor Free Disk Free ISE DATE TIME SIZE MEMORY T delete rename mem delete rename 3 Using the alpha keys above and below the display create a file name such as AITEST 12 JAN 21 09 09 A E C D E F 5 Hemor Used Ze Disk Used Hemor Free rad Disk Free Enter neu name U jT O CATE ES TIME HAME DATE TIME MEMORY F 4 Then press EXIT to enter the file name Press EXIT again EXIT EXIT Notice the file name appears at the lower left corner of the display This indicates that this is the active measurement file All of our acoustic intensity data records will be stored in t
198. ch of the frequencies Press RT60 B to view the RT60 register ZH 22 15 34 37 REPLACE AVERAGE Auto RE Auto AL note Hote SPL WERAGED LINEAR FEPEAT End Dual LIHEHE 26Hz 16kHz FESET 26 FEB 923 15 17 53 TH 232 1 66kHz 543 Channel 1 af 2 usTIME Ef Td 15 ETEA 4 195 ct 1 1868 Hager ees 2 4 a A ok Ley 55 93 8 aa A S z HERE dotted crar ROOMS lthresh hthresh A Prev H Hext DATA SOLID DOTTED BOTH 9 17 2900B TRAINING MANUAL In order to store data in the RT60 register you must first clear out any old RT60 data that may already reside there 8 Press RESET D to clear the RT60 register as OCT 16 46 26 l RESET Huto RE puta HU note D RT amp B Hote SPL VERAGED AS A A o LIHEAR FEFEAT HL He bT IME Input 1 LINEAR 26Hz 24kHz RESET 8 OCT 94 15 82 54 SG E A E RELE ti E L arm E D SHH Hz Leo ETEA DATA ee FT b 1 08 RALG al AutoTH Max 25 8 5 H Loc THCH SPEED H Hz Ssd Hz ZH both creses ROOMS lthresh hthresh Auto TH SOLID DOTTED edit 9 Press YES A to verify that you wish to erase the RT60 data Q base HS OCT 16 49 36 Ces 1 4b Erase ET6B database ETEB SPL WERAGED ool AA e ee ee a ee HO ee at A LIHEAR EEFEHT B A ISIS bTIME Ineut 1 LINEAR 28Hz 26kHz RESET 63 OCT 94 15 02 54 SG DU Er MEC EIN E MI E AN lA a a at 75 8 SHH Hz Leo ET amp B DATA m FRT H 1 66 AWG 61 HutaTH Max 25 6 a A aa TACH SPEED F EH bath ceses ROOMS Notice tha
199. ctrum k 20 FEB 10 44 54 9U 28 U 2084 AUTO RA Ineuts TEST E SPL 58 0450 190 Ua RT N RR fares Sine ET RT A A A E eh Te ER a ae ae R oe 9 N EXF HEHT IHL Dual LINEAR 1Hz 1BkHz La STOF 7H FEB 98 18 44 25 Eh 2 MA RR A AR x FILTER H 1 MI Hz Leo La 1 mc icu ue ro ass aa a d esc pd DIFF Ph 111 8 Sn 145 340 TACH 4 46 SPEED B d dotted crar zi 15k SAME eFEHHGE Hz CET 1 ZzBk H S T 13 Press the 20 10k N key This is what effect the 20 10kHz fil O To ter has on a spectrum N 20 PEP 1 4r 29 Q U z8 U zm U AUTO EA inruts TEST SPL 64 590 LA EXPONENTIAL Dual LIHEHE 26Hz 16kHz STOF zH FEB 98 18 47 87 gt LI mI EG Es FILTER 14 25 8 Hz Les d te 1 E Doe HERI DRE REA e DIFF Phz111 9 Sn 146 43 FEM TACH 4 46 SPEED B d z dotted crar 1 16k 26 16k SAME aRAHGE 14 Press the Exit hardkey to return to the System menu R Hz b Hz b Lj IHMITIAL A WGeT C WGT zBk zB zb5k EXIT Setting the Clock The analyzer has a built in internal real time clock for time stamping measurements 2 27 2900B TRAINING MANUAL 1 Press the clock L key as 16 88 17 Chanls SLM A STANDRD CROSS INTENS Y UNITS FILTER CLASS r 9 SPL EB ma Bites hehehe EXPOHEHTIBRL 148 Dual LIHEHE 26Hz ZBk Hz RESET 19 FEB 93 16 65 48 erreorrrrrrrrrrrrrnnnrrnrnrnn rann FILTER i4 25 8 Hz L Z o 1 p a de r D DIFF Phe 52 2 Sn 2 4z RERO TACH 4 46 SPEED B d z5 H
200. cy information within a relatively small band say 1200 Hz to 1800 Hz With FFTZOOM you can apply all 800 lines of resolution to this section 1 Press SYSTEM to return to the main System menu 7 15 2900B TRAINING MANUAL RESET R S 7 16 Choose FILTER G to enter the filter menu B3 i BS 1235 49 Chanls SLM A STHHDRD CROSS INTENSY UNITS FILTER CLASS I i G zu Bm 18 TI LIMEHE STHGLE zB mg Input 1 LINEAR iHz i amp BkHz STOP G3 JAH 28 6911938 54 Bv A E E FREQ 153 37 5HHz HSHH Channel 1 of 1 NORMAL En Sr Se 18 1 REM TACH 8 8 SPEED 6 4 s s QLLe0 CESE BG EN dotted INITIA 170 IG G H INPUT COLOR MLS FILES RESETS Before selecting the zoom multiplier first move the cursor to a center frequency about which you would like to apply the zoom For the example move the cursor to 1650 Hz Then press FFTZOOM M az Ian Qs 145 15 1 loct 1 3oct lona short reverse I G 28 000A 14 PT E an eee aah Sw ees O AA a A ee LINEAR SIHEBLE zB BRR Ineut 1 LIHEHE 1Hz 16kHz Hi JAN 98 36 ET P ALA AE E E E Ais Said UT FREQ 159 37 5RHHz HSHH Channel 1 of 1 L d 37 2 TACH 6 8 SPEED B a datted crar WIHDOW BASE Ed Notice that you have a number of zoom multiplier options from which to choose Select 4 C for this example az JON BB 16 12 1 2 g 16 32 Ed 8 8 SPEED B a dotted crar BHSE Hz Note that the frequency span has changed It is now 1337 5 Hz t
201. d C TRE a A FILTER 14 25 8 Hz Les Channel 1 of 2 HORMAL d 3735 8 A 34 49 54 r DA E a UR ER a a as a aa aa a DIFF Pbs nz B Ens 7 45 REM gs TACH B H SPEED B B 75 8 Hz Bae Hz 206 QL HZ da CESPE INITIAL 1 0 51G GEN IHFPLT clock COLOR MLS FILES RESETS 2 Press one of the following keys to perform the desired reset 24 EEE 13 54 24 E MEMEY E UNITS R SETUP R RT B R USER R MACRO R STATS E HORM 116 aa r REM SIS ROOMS R MEMRY A This will perform a reset of the internal RAM of the instrument and clear out all stored data and all user defined setups bringing the unit to a default state R UNITS B This will perform a reset of the user defined Units only R SETUP C This will perform a reset of the user defined Setups only 2 30 EXIT R RT60 D R USER E R MACRO F R STATS G 2900B TRAINING MANUAL This will perform a reset of the RT60 data only This will perform a reset of the user defined Weighting curves only This will perform a reset of the user defined Macros only This will perform a reset of the Statistics tables only After pressing one of the above mentioned keys a message will appear on the upper right side of the display ARE YOU SURE to make sure that you really want to perform the RESET ZB FEB 18 55 31 YES HO 126 QD ae ARE VOU SURE Bia 106 r A A A A L RR RR RT A R eed E RUE E E EVPONENTIHL i Dual LINEAR 2BHz 16kHz RESET ree E me drid
202. d Gun WET Sener AO A RR A oo om EXF HEHT T DL 1 Dual LIHEHE 28Hz 28k Hz STOP HS OCT 94 15 56 42 54 ec Be a ee SE xx e 604 06 ox ox oro X CE X wow X X Xx ee ae cox vox FILTER H 1 S ai Hz L3 Channel 1 of 2 HORMAL d B 66 2 Ab nh A nM MV ws FH HS EZ 3 RE i TACH H H SPEED Bg d LA Hz R INITIAL ROOMS UsREM STAT Mx spec TRIG SETUP FILES AUTOS TR Press the format F key to format the disk in the disk drive If the disk is DOS pre formatted proceed to the next step NOTE 2900B TRAINING MANUAL 3 Select the desired file to be transferred to the floppy disk by using the T C or L K key Bi OCT 16 18 24 create RECORDS disk T Format Memoria Used ZEE Zd Q Used 761256 Hemor Free d Vu Disk Free 695296 DATE TIME HAME DATE ISK TIME SIZE DISK mem delete rename delete rename 4 Press the disk D key HS OCT 16 16 24 create FECORDS Hemor Used zZ6624 Memoria Free 22Sdrz DISK 7 delete rename men delete rename The disk drive will activate and the following sequence of mes sages will appear on the upper right side of the display A Opening disk file B Copying file to disk C Copy done D O K to remove disk Do not remove the floppy disk from the disk drive until the ana lyzer tells you that it is okay to remove the disk The file transfer will not be completed if the disk is removed prematurely The file name will now appear in the section of
203. d analog filter weighting for the sound level meter function keys 1 N Mon 15 17 56 H S T CMS T 1 26k 2B zBk 1 16k zB 18k Hote TEST 1 31 2968 14 MEE EXPONENTIAL 18 Inrut 1 LINEAR 28Hz 26kHz ST 11 OCT 94 15 17 13 24 N is i tee ki A A A A Ee dca ech be ne cer E Sed cme ae Be FILTER 24 75A Hz Leo Channel 1 of 1 HORMAL d 47 7 Ee 66 0 CHED S24 L S2 6 Max 2 3 B Hl Hz M TG TG dotted creer INITIAL A WiT CWT 1 Zbk 2H6 Z 6k 1 ibk Zzu 1 k 4 Press the EXIT hardkey to return to the Main menu 2900B TRAINING MANUAL 5 Press the RUN hardkey to begin the measurement Wide Dynamic Range Sound Level Meter No Frequency Weighting In this mode the two A D convertors usually used for each of the two microphone inputs are used together offset to measure a single channel providing a primary indicator range in excess of 80 dB This means that the Type 1 specifications correspond ing to ANSI S1 4 1983 and IEC 651 and IEC 804 are met over the entire 80 dB dynamic range of the instrument Frequency analy sis is not provided in this mode of operation 1 Press the SLM hardkey to access the WDR SLM operating SLM mode ut 212410 g A WiGT CGT 26 26k note l SPL 22 6168 28 WD UE A CEDE V RC a ASTU UC ERE UE RC STE R E NCC UAE CALO DRE ER UL E UNDO a ELO D Inrut 1 SIBI STOP az JAN 98 23 22 43 EHI ALAS 24 6 E 65 a EN SLM DATA ranae 115 IHITIRL SLO FAST IMPULSE LEG STHT S
204. d as a source of impacts on the floor above and the resulting sound pressure level produced in the room below is measured in 1 3 octave frequency bands Noise Ratings 2900B TRAINING MANUAL Resultant measurement choices are found at the bottom of the screen in either the ASTM or ISO menus These include Ln ASTM and Ln and L nT ISO Noise Criterion NC A SCREEN SYSTEM EXIT ala RESET R S A single number technique for representing the character of steady indoor background noise is based on the 1957 Noise Cri teria Curves These are a set of similar octave band reference curves which are overlaid graphically upon an octave frequency spectrum measured in the room to represent the background noise Each of the curves is designated by a number called the Noise Criterion which represents the value of sound pressure level corresponding to the 1 kHz band Since the curves are stored in the 29006 this function can be performed automati cally using a displayed 1 1 octave spectrum which has either just been measured or has been recalled from memory 1 To enter the 1 octave mode press SYSTEM press FILTER G and then press 14 OCT A 2 Press Exit twice to get back to the main menu 3 Press R S to begin the measurement To stop the measure ment press RS again 9 35 2900B TRAINING MANUAL gt O 4 While in the Main menu press ROOMS I and then NC A to look at the NC curve o 975 23591 HC HF
205. e HRORRHS HSARA YE SE 1 of 1 HORMAL zi aa ta cel cat cu Ca tas sao heya A a CRURA AUT UE A Sor wel aur cout dd cao Naan Ecc ES Sees RE REN a TACH HLH SPEED B El QG am Z 00m 1 16606 09090 Z A datted crar IHITIHL T L IHE 300 690 1209 2406 dana 9688 19768 The message DC output O XXXXXX will appear on the upper right side of the display The XXXXXX indicates which fre quency band or SLM parameter is to be represented by the DC output voltage 13 or lr 18 28 3z2B8BRC DC out I Fort KEY A KEY E E Ca curo vx c c r 0 DC output 3 S 1258 0006 SPL B S688 TE gX RR RR A RR et KR NN NR WE RR ee NN RR ae ee 1 EXPOHEHTIAL 1 48 Inrut 1 LINEAR 2B8Hz zBkHz RESET 19 FEB 98 1 48 36 JB rice RRR IRC duh as o RR RRR TE at de eros TR Lue OR cay RRR E E TAT RR R R RR RAS a Tea FEEL Aa BHARAHz HSHH Channel 1 of 1 NORMAL d 33 3 E 6 6 KT LLL LLL LLLLLLLLZG L LZIIL BEN et TACH a d SPEED 4 6 aa BOB 00m _ 1 10000 0060 Z A DC output IHITIRL T LIHK Jag ea 1288 2468 4568 3688 19288 2 While the message is displayed press the horizontal arrow keys to select a frequency or sound level meter parameter After selection of the desired frequency parameter the mes sage will disappear I O port control Key A and Key B The most common use of these keys is in conjunction with the control Larson Davis Model 2260 Intensity probe which has two keys thumb and forefinger on the handle These two keys can be
206. e 3 Channel 1 of ES HORMAL d 21 3 a KMS L O rim Ie le PHOHS ri A Loc TACH 6 6 SPEED B 14 De A ee aa auc mE M wok Hz 2H H Hz Hl kHz H dotted crsr IHITIHL E DMS usRPH STAT Hx S5rec F TEIG SETUP FILES AUTOSTE Select a range to optimize the spectra in the display without overloading the analyzer To do this first press the RANGE key Then press the down arrow key until the overload OVL is seen on the screen Next press the up arrow key until the OVL disappears Press the CURSOR key to select which cursor options you desire to use Press one of the following softkeys the dotted P will display a d the solid O will display s the both N will display a N which indicates the amplitude dif ference between the two cursors H3 OCT 14 35 14 98 SPL 1 7458 EXPOMENTIAL 1 5 Dual Ma eder zBHz es STOP 24 Hz a ied AS SER Did 6H E TACH 8 8 SPEED B a dotted crar BOTH SOLID DOTTED The filter band number and frequency are shown for the cur rent cursor position Press the left or right arrow keys to move the cursor to the desired frequency 10 Press the EXIT hardkey to return to the Main Menu 2900B TRAINING MANUAL Main Menu Selecting a display parameter 1 4 Normal A Leq B Min C Max D SEL E Max Spec L 1 Press one of the following keys to select the desired display parameters H3 OCT 15 62 83 NORMAL
207. e ES d OE RC COE CR ay cS UE TRR deo ates as OE cR UE R 7 R INDE EXF HEHT T DL 1 8 Ineut 1 LINEAR 28Hz 26kHz FESET 18 MAF 94 16 61 35 ro Mica AO RT ey Teas ds TM R ae N N dues Va cup ATA X D JO O o T RR RR a ce NOA UE FEEL QG ARRAH H4HH Channel 1 of 1 HORMAL g 3 2 B 21 1 Loc TACH B B SPEED B a m DOS EUER m S E aM ULB ROOMS us EFI STAT Mx Srec F TRIG SETUP FILES AUTOSTR Setting up the FFT 1 The next step is to configure the RTA to acquire single chan nel FFT data First press SYSTEM Select channels A to enable the single channel capabilities of the Model 2900B 1 2 O 2 2900B TRAINING MANUAL this will be indicated on the righte side of display as shown in the following screen If you are using a Model 2800B this step is unnecessary aig nme SLM A STAHDED CROSS IHTEMSVv UNITS FILTER CLASS SFL B Baa Bl te hee eene EXPOHEHTIBL 1 8 Inrut 1 LINEAR bHz Z6kHz RESET z JAN 93 23 38 41 IHH FILTER 16 48 8 Hz Les gu alt L of 1 i a D DIFF Ph 52 28 Sn 2 43 FEM i TACH 9 9 SPEED Bg d eee eee ee ee O re eee 5 8 Hz EZ Hz 29 BLC HZ OFF INITIAL 1 0 SIG GEH INPUT clock COLOR MLS FILES RESET S To configure the RTA for FFT narrowband analysis first press FILTER G 82 igh 23139149 Chanls SLM A STAHDED CROSS IHTEMEV UNITS CLASS SFL B HaHa 3H A A IA A O AE O ne EXPOHENTIAL 16 Inrut 1 LINEAR 2B8Hz zBkHz RESET 2 JAN 93 23 38 41 DE WE XN XR RR RR N K
208. e See A AD N ey a a Oe oe FILTER 14 75 8 Hz Leo Jenae 1 oil HORAL D DIFF Ph 54 4 Sn 2 73 ENS TACH 4H SPEED B El 25 5 Hz 636 Hz ZO HE HZ dotted crar INITIAL A WGT C WGET 2H8k 2B Z6k 1 16k zBH 1Bk SAME aRAHGE 3 Press the EXIT hardkey to return to the SYSTEM menu EXIT Verifying analog filters You may verify the operation of the analog filters by performing the following from the SYSTEM Menu 1 Press STANDARD C and Chanls A keys to place the ana lyzer in standard 1 channel mode ZB FEB 18 18 63 FChanlsf SLM A YSTHHDED CROSS INTENSY UNITS FILTER CLASS lin b i ue ca int dr DES US d TRA NEL DROP QR CE O cac o ca dh rco XL Ge a AAA SFL EB BEBA a2 K co e D Ra ah RR AR INO CK KO a RS ORO GC TRE DR CO DCN KO Y cO D DX XD Om dec N RC hc UNCIAS C s R ces D EXPOHENTIAL 148 Input 1 LINEAR 28Hz 26kH RESET 378 FEB 98 18 16 51 DE LT FILTER 14 25 8 Hz Les Channel 1 of 1 HORMAL d 4 4 39 2 54 ai A e A RT NR a A o A E o AO E a ey A A DIFF Fhz Sd d 5n vara PEM a TACH 4 8 SPEED 4 8 25 8 Hz 6360 Hz 206 QL HZ datted crar INITIAL I 70 SIG GEH IHFLT clock COLOF MLS FILES RESETS 2 24 EXIT 2 6 2900B TRAINING MANUAL Connect the Noise generator source output to the input of CH 1 The output jack is located on the top of the analyzer labeled source output You must use a cable that has an 2 5 mm mini phone plug on one end to a BNC connector on the other Thi
209. e below az BET 15 42 63 NOREL Ley MIH HAs SEL DISPLAY note DETECTE i SPL 1 7458 TH O ks at Ga eue uv a RE Bee eR HHT EXPONENTIAL Wal LINEAR 28Hz z WkHz C STOP AS OCT 94 14 35 88 54 bo A M C es A FILTER H 1 2A i Channel 1 EE KS ld A ha wae as oo ae a ee PHONES 59 1 Loc TACH 6 6 SPEED B amp 15 AA A id uad Hoy dod a T Cu eid A Po RT cat ies aah raed Eo LA A an tM Mac te 39 Hz Sp D Hz Hz tdotted crsr IHITIHL usREPHM STHT Mx Shee F TEIG SETUF FILES AUTOSTR 2900B TRAINING MANUAL Display weighting V F 1 1 A 1 3 B NOTE SUM E Your analyzer has the capability of digitally weighting the dis played data This feature is independent to the input signal ana log weighting that is selected from the Input menu 1 Press the Display F key to access the digital display menu 05 gT 5 03 04 NORMAL Lea MIN MBR SEL note DETECIR SPL 1 7458 rur Ep DD EXPONENT IRL 1 8 ual LINEAR 26Hz 26kHz STUP 3 OCT 94 14 35 08 54 E AR RT 9 7979 97 9 T R 7 NA RR E E E p FILTER 1 MIS Hz L 3 Channel 1 of 2 HORMAL d 15 7 A 56 6 AB sb ss ss O DEMNM PHOHS T3 1 ma LOE i TACH Ha SPEED Bg d woh H ah H Hz HZ dotted crar INITIAL FOOMS usEPH STAT Hx Shee F TEIG SETUP FILES AUTOSTR 2 Press one of the following keys to select the desired display SU SETUSER note Multi 15 IO N N AN RR RS A RO AR O A NN Hotes SPL Z S568 9H r A A ae A ONDORD AC A A Ge a ON ERE EEE
210. e changed from negative to positive by pressing SLOPE L ur cuo M PES s iiia aa 3H Ea RR R R a e A RR RR RR E RRR RR RRR RRR at nde e as R Sa RE a E ad UHT MARNLIAL ACCEPT LIHEHR 1Hz RESET Br JOH 92 zB A A3 1258Hz Fara Hubo eee 7 17 zB e O GG Ge GS OG IS A A A IA PME Peauercu AW AAGA y id B Ch2 B PEM g A a a a as in td cl WE a e lina da a 0 0 SPEED 5 0 an E DUS tris level INITIAL HLTERH BWHORM Pick DELAY 2 DELAY OFF 34 Press DELAY N to establish a pretrigger on channel one 7o N ub at uro MEL T uc ARES LEF aa 3H TA e A RR ER EE ae ars RKR ay ER A a wc ated COUHT MANWAL ACCEPT Dual LINEAR l1Hz 18kHz RESET Br JAH 98S 28 48 59 TE xR RR RRR RKR R RR RRR RR Xo XC ROS RR NC AO a FEEL A3 1258Hz ESAA Huto Spectrum D i d 11 3 B 17 7 ae i cee R Sag Re II eden taps Seance cee ee R IE Base Freauenc z AA HHHH tig td Bs Ch2 B REM TACH 8 6 SPEED 4 6 25 Ea T S S H bie ig INITIAL RLTERH EWHORM P lt gt R SLOPE LEVEL 2 DELAY OFF 11 24 EXIT RESET R S 2900B TRAINING MANUAL 35 Press the left arrow hard key to increment the desired nega tive delay 20 samples for instance This value may need to be experimented with to make sure that the time domain impulse has been fully captured If this signal is not fully captured unclipped measurement errors will result er JBN 28 58 58 A SPECT TIME note i LEF B ae Be Pas SP xe se cur RC RC RR A O A EA push MANUAL ACCEPT EAR 1Hz
211. e or more of the following Neutral Spectrum N Rumbly spectrum R Hissy Spectrum H tonal Spectrum T and Acoustically Induced perceptible vibration Va and or Vb As with the NC and NR rating procedures the steady back ground noise spectrum is displayed in the 1 1 octave band widths format The main difference is the low frequency needs to be set with a low limit frequency of 1 Hz This is done by pressing INPUT K in the System menu and setting the fre quency limits to 1 10K M If this low limit isn t set the instru ment will give you an error message 2900B TRAINING MANUAL OW To access RC simply press RC C in the Rooms menu ape ed HC HF EC surface volume RT amp e8 SPL 2z 24500 pP EXPONENT IAL ra BB 1 l Dual CINEAR IHz 1BkHz STOP 71 FEB 92 975 795 09 oc SARE A A Tg m a a E RS HRS ECT Je ae T FILTEF 6 HG Hz L 1 Channel 1 of 2 NORMAL d 33 2 A 44 1 ere RE 37 H e TACH BH SPEED B a dotted crar QUECE RECEIVE BEHCK GD CLR PG Hz ASTM 150 9 37 2900B TRAINING MANUAL 9 38 CHAPTER Statistics and Ln Calculations Statistical analysis can be performed with the analyzer in either the 1 1 or 1 3 octave frequency bandwidths 1 Press the STAT K key from the Main menu to access the sta tistics menu K ae UE Br 35 39 ROEMAL Lea HIH HAR SEL DISPLAY nate DETECTA PL EB Bee ab Wt a ue Se KERRE t a e cw ERUNT ORI E dep cen i Sah C
212. e the FILES Menu AS OCT 19 54 18 create RECORDS G disk t format Memoria Used 2645 rk Used Hemor Free 259042 Disk Free EOR gt BI DATE TIME HAME CATE SK TIME SIZE MEMORY menm delete rename delete rename The file name PLANT that you selected will appear on the lower left side of the display This indicates that this is the active file and all subsequent data storage will be placed into this file 5 BD ea nate B S 15 55 09 WORMAL L MIH MAH SEL DISPLAY t DETECTE i SPL 14 5568 TH al A a A ce A A A A A A ar ee OW UE EXPOWEWT IAL A Dual LIHEHR 2A4Hz 26k Hz i STOP 63 OCT 94 15 38 42 Sp ba HHIH a A A o 9 A A A A a a ar FILTER 1 z 24 Hz LA Channel 1 of 2 HORMAL i g K E 66 2 za ID LEER PHOWS 63 2 Cor ab TACH H a SPEED B a S Z Hl kHz dotted crsr PLANT STAT Mx S5rFec F TEIG SETUF FILES AUTOSTE 2900B TRAINING MANUAL Renaming a file 1 Press the FILES O key found in either the Main Menu or the System Menu Select the file PLANT or a desired file to be renamed by using the T C or 1 K key az OCT 15 59 57 guial MR Q disk t Format Memor Used lek Used Hemor Free 2298043 Disk Free HEMOR OOO DIE MAME DATE TIME SIZE HAME DATE TIME SIZE MEMORY 7 delete rename mem delete rename Press the rename J key Ed OCT 16 23 26 create FECORDS T disk t Format Memor Used erar Disk Used Hemor Free 19824 Disk Free Ee OOOO DISSE MA
213. e to humidity Basic Acoustics 4 6 2900B TRAINING MANUAL LS NEAR FIELD AND FAR FIELD Near field the distance from a noise source less than 1 wavelength of the lowest frequency of interest away from the noise source or 2 times the dimension of the test item Difficult to make measurements in the near field Far field the area beyond the near field v 1 En composed of the free field and fCRACO reverberant field i Basic Acoustics LS FAR FIELD Free field the area between the near and reverberant field this is the area where measurements should be made this area is characterized by a 6 dB drop in sound pressure per doubling of distance Reverberant field the area away from the sound source where reflections from walls and other objects can be just as strong as the sound you are trying to characterize Basic Acoustics 4 7 2900B TRAINING MANUAL OPERATOR POSITION A IE Q0___RP a MEER EO QKXr Q gt ooo m A The operator should ba positioned at least 1 meter behind the microphone The operators body should be t the side of the microphone Body reflection causas low frequency errors These errors occur below 500 Hz and can be as large as 6 dB Uge a tripod if possible 1 i e a Acoustic SOUND LEVEL METER Features measures sound pressure level SPL weighted and unweighted SPL rms weighted and unweighted
214. ed ALTEST 5 gt J08 S3PHRT S2AREA S gt EDIT Ci F4 2 C2 F4 2 F3 F2 20 Press Power A to perform the sound power summation 13 de 1 35 61 F2 P I F3 HPP F4 FHU note SPTEST FR HT dd E SH O a fave E cay CRI C XX ae Sey CC CL e reb STHGLE 7h l al LINEAR 28Hz iBkHz RESET 13 JON 93 01 34 18 FILTER R25 315 Hz L73 BI Four ro ine d 18 44 ana Diam SH IIIA UNE PI ERA EIL CC C 1 fcm 34 64 Hz AZ BdBrgl l JoB FTES REM PART FRONT at E AA A Ee ac NN N RR ER N RRR NNN RR N R R R RRR N AREA POIHTi1 25 8 Hz Sea Hz 16 8kHz z A dotted crsr RITEST S gt JOB S3PHRT S gt AREA SEDIT CI F4 2 C24 F4 2 F3 F2 On the display you will see the total sound power spectra of the specified part 13 3e 81 35 38 Power F2 P I F3 WPP F4 FHU nate Hote dE ell Eire LIMEHR SINGLE 28 iB Dual LIHMEHR 258Hz l8kHz RESET 13 JHH 22 ih 48 41 FILTEE L ER 78 L TdEGl B AREA 25 8 Hz 500 Hz 104 BkHz H dotted_ crar AITEST SJOB S PARET S AFEA S EDIT CitF4 2 Czx Fd z F3 FZ At the right of the display you can read the values of the total overall sound power Linear amp A Weighted of the part plus the sound power at each 1 3 octave band 2900B TRAINING MANUAL 21 To view the sound power of a specific area of a part press S gt EDIT L Enter the desired area and press EXIT 13 epa B1 32 807 Power F2 P I F3 HPP F4 FHU note STEST FEDHT POINTI dE F ZD m LINEAR SINGLE Dual HE E FILTER 25 315
215. eighting filter is active The weighting can be modified from the Weight menu 1 Press the WEIGHT M key a 14 54 35 NORMAL Lea MIH MB SEL DISPLAY note DETECTE 26 3968 a H Inrut 1 LIHEHE 2BHz 24kHz STOP 11 OCT 94 14 54 69 Gea eg Mca perineal Bea FILTER Ha G ZD Hz Les Channel 1 of 1 HORMAL d 37 4 a 58 7 SW i EE Z RENE PRECEPIT IDEM in eT Haz BH 4d E SLM DATA dotted crsr SLOW FAST IMPULSE LEG lle iaht SETUP FILES AUT STE This Menu permits the user to select the weightings for both the sound level meter function and the frequency analysis function from the same menu These weightings are inde pendent from one another The weightings represented by the softkeys A F are for the frequency analysis function and the weightings represented by the softkeys I N are for the sound level meter function 2 Press the desired analog filter weighting for the frequency analysis function keys A F H S T CMS T 1 26k 29 29 1 16k zB8 18k Hate TEST 1 31 2200 146 d d dan ROL N n TR r A A EXPONENTIAL m Inrut 1 LINERR BHz 24kH3 STOP 11 OCT 9m pt we ee dede ce ve e Ae ey sp ce eae ane te ees cus cue ae cd a Ves wo ee Gs ee ED ee a a FILTER 24 z756 Hz Leo Channel 1 af 1 HORMAL d 47 7 B 66 9 11 OCT 15 17 56 1258 L y A WEI GHT d LOC N SLOW 77 K E E O Rr E EE Ds A a 57 6 hax ma E SLM DATA dotted crsr INITIAL CET 1 26k 26 26k 1 16k 29 19 3 Press the desire
216. el 1 ae z DOE TAL DIFF Ph 98 4 Sn 57 46 TACH H H SPEED B d recall data REM E ze H Hz ROOMS DELETE In the field on the top right side of the display type in 0004 0006 This tells the 2900B that you want to average the 3 receiving room spectra 23 FEB 11 15 54 186 AVERAGE 6004 r RRR RRR EE RR RN ante lees a E e a e K R tlt zr PRR SPELE zB mg HEAR 28Hz 2BkHz 98 10 1910 NSS 1 oF 3 NORMAL r DIFF pr 35 2 pe MBS 46 TACH BH SPEED aa brec all dataRo00mns E 9 30 EXIT STORE CLEAR RECALL EXIT 2900B TRAINING MANUAL 15 Press EXIT to initiate the averaging calculation The new spectrum that appears in the display is the average of the 3 receiving room spectra m 11 11 12 W Fall E AVE E MA E SUM KEEP Hate RECIEVE SPL AVERAGEL LIHMEHR SINGLE A Dual LIHEBFE 2BHz Sal Hz RESET 23 FEB 98 18 22 38 FILTER 14 25 8 Hz L 3 Channel 1 S z HORMAL de 45 2 HS DIFF Ph 84 8 Sns 22 35 TACH 8 8 SPEED B a recall data REM one n E ROOMS DELETE 16 Press STORE to save the averaged receiving room spectra into the ROOMS file Notice that it is stored as Normal 8 23 FEB 11 17 88 W FAII R RUF B MEM RSMO KFFP a i HOLE s f SPL EFAGED LIEB SHE 26 66 HEAR EE Hz we Channel 1 o 2 HORMAL DIFF Ph 84 8 Sn 22 35 TACH p m SPEED B A brec all data REM s Ej x E ROOMS DELETE 17 Press KEEP H to get back to the Noise m
217. enu and then press 23 FEB 11 17 55 hi Fa11 FR ALF E MAH E SHM Cere 140 r o goto E Harmal e STOR Hate RECIEUE RAGED poe IER 26 90 LTHEAR Sm zBkHz RESET 23 Fii PEE n aa 22135 FIL Hz Le E ee 1 o 2 HORMAL 5 DIFF Ph 84 8 Sn 22 35 TACH 8 8 SPEED B B brec all data REM ra a El E ROOMS DELETE 18 Recall the background spectrum by pushing the RECALL hard key and locating memory 7 Now push the KEEP H key to keep the spectra and return to the main menu 23 FEB 13 58 47 WORMAL Lex MIH MB SEL DISPLAY note DETECTA 1a v g AUN CST mode d w N Je E TR da Att 9 e ey cat Sime Joe UO Mec Ma Rr I at Seat 9 ve a duse C Hate BACKGHE p SF zB 9990 a r E N RR NN NR RN NE 7 N A RE M LIHEAR S INGLE zu HARE Dual LIHEHR 2bHz 26k Hz RESET 23 FEB 93 16 33 11 en r A AA eds Mes ar de RC OE RIEN stam RN H sig Gay Qe UR D ody Mah s FILTER 14 z25 Q Hz L7 3 de Channel 1 Ale Z SE hi 4a m A ooo o s o o o x xx ae Be ee ee we EE DIFF Phz 55 3 Sn 2 21 En E TACH 9 9 SPEED Ha H Hz Eod Hz dotted crarb 20015 ROOMS WweRPM STAT nx Gree F TEIG SETLIP FILES AUTOSTE 9 31 2900B TRAINING MANUAL 19 Return to the Rooms menu by pressing ROOMS Y Enter Y O this background spectrum by pushing the SET gt L and L BACK GD O keys Exit to the Main menu by pressing the EXIT key EN 23 FEB 13 28 8 HORMAL Lea MIH MAs SEL DISPLAY note DETECTE 1a JI Hate BACKGHE
218. equency vs RPM measurement first 13 21 2900B TRAINING MANUAL SHIFT RESET 13 22 r 9 R S RESET R S 1 Press BORDER L to change the trace display to frequency 16 SEL 15 16 46 SLOPE elenel TAGERES s SFHM VIDEO BOARS note WIDTH SOURCE IS TACH IHPLT Qe 92H88 i1 ba sored E LR tin eir ood arat quss ds die rem Ze A eta ERR D EXPOWEWT IAL 1 5d Input 1 LIHEBR 1Hz l1B8kHz OCT 94 18 18 C FRE DNS MEA L ld el bo lL GaGa L 65 T Al Aaa oA Aaa lalalala 30600 REM TB crar DCHOTOR STATUS HIDE TACHSEAE ORDER CAL PEN CHAMHEL You will use the current PEN frequencies If you wish to change them refer to the previous section vsRPM Graphics Note that the frequencies or orders need to be established before the test You cannot change PEN frequencies or orders after the mea surement is complete and redraw the display as you did with the byTACH autostore data Verify that the output of the tachometer is connected to the TACH INPUT jack of the Model 2900 Also check that the accel erometer is connected either via a 950B or AD045 adaptor to the Channel 1 input Make sure that your tachometer is turned on and is reading an accurate tach signal from the rotating test item that is below the beginning of our X SPAN 500 RPM 2 Press SHIFT then R S to reset the measurement you are now ready to begin the live vsRPM measurement 3 Press R S to initiate the measurement Notice that s
219. er emits power in watts The result is a temperature e A sound source emits sound in watts The result is sound pressure Acoustic Intensity What is it e Sound Intensity is a vector quantity It describes the net amount and direction of flow of acoustic power at a point in space e Sound Intensity multiplied times the area over a measured surface yields sound power 1 I2 Advantages of Acoustic Intensity Does not require a special test space can be done in situ e Measurements not affected by steady ambient noise e Easy conversion to Sound Power e Can be used to locate sound sources e Provides a means to rank sound sources 12 2 2900B TRAINING MANUAL Acoustic Intensity measurement hardware e Microphone probe and a spectrum analyzer e Spectrum analyzer should make measurements in octave bands and or FFT e Spectrum Analyzer should make measurements in real time CCC COCO E E Y EA 12 3 2900B TRAINING MANUAL Acoustic Intensity nuts amp bolts e Acoustic Intensity measurements require simultaneous mea surement of sound pressure and particle velocity i pev e The velocity is estimated by measuring a pressure gradient sound pressure difference between the two microphones v 1 p dp dr dt vp 1 p Pa Pp dr dt p fluid density dp dr Pp P Jr direction Time Domain e Pressure estimated by averaging the two microphone pres s
220. eraging times will be presented B3 SA 19 22 85 1 64 1 32 1 16 2 45868 1 8 1 LIHEBR 2AH 24kHz STOP AS OCT 94 15 21 55 5B eta CIT EEMP immi a a oes ee ab R si cee a es 8 FILTER H 1 15 Hz Leo Channel 1 of 2 HORMAL d a 58 1 tol ERE PPP PHOHS 54 4 SPL FB ade eo a A O E A A E EXPONENTIAL Dua TACH 8 8 SPEED 4 4 4 Press the EXIT hardkey to return to the Main Menu EXIT Special Measurements ROOMS I Room Acoustics vsRPM J Versus RPM measurements STAT K Statistics and Ln calculations Each of these measurements and keys will be discussed in detail later in the manual Triggering The analyzer has the capability to begin averaging automatically when a specific trigger criteria has been satisfied The analyzer can trigger in both the Frequency domain and the Time domain FFT mode only Frequency domain triggering 1 Press the F TRIG M key 43 OCT 15 26 85 HORMAL Lea MIH MAs SEL DISPLAY note DETECTR M a i babe twee eana a aa a TET SPL 14 6658 E E TT enero YE a iSo dtes Pen ee EXF HEHT HL 1 78 i Dual LINEAR ZBHz ZzBkHz SIOR G3 OCT 94 15 25 56 JB xb X o o kk ko ko t x t or age or f xk n nm m n en eR err rn FILTER H 1 Mz Hz Leo i Channel 1 of 2 HORMAL E 56 5 I I I d s ob i um PHONES 63 4 aH aan TACH 4 46 SPEED B d wok Hz oA D Hz SNS ds dotted crar IHITIHL usREFHM STHT Mx Spec F TRIG SETUP FILES AUTOSTR gt I
221. es of the 2900 by making vibration measurements on plate that is attached to a dc motor As the motor runs up or increases in RPM the vibration frequencies of the plate will also shift upward as a function of speed You will measure the vibration using an accelerometer although other transducers could be used for this test as well The TACH INPUT of the 2900 is designed to be used with a tachometer that outputs an analog pulse TTL train that is pro portional to the rate of rotation of the test device For this test you will use an optical pickup in conjunction with the Larson Davis Model T100 tachometer to detect one pulse per revolution of the dc motor byTACH Autostore Measurements The first method that you will use to acquire variable RPM data is the Autostore byTach feature This method is very similar to the Autostore byTime function The key difference that instead of gathering spectra over a time duration at a specified time interval you will capture spectra over a range of RPM values at a predetermined RPM delta 13 1 2900B TRAINING MANUAL For this test you will capture spectra from the de motor plate as it runs up in speed between 500 RPM and 3000 RPM at 20 RPM increments using autostore The end result will be a set of frequency spectra starting at 500 RPM with roughly 20 RPM increments between them 500 520 540 The last spectrum acquired will be at 3000 RPM Setting up the 2900 Measurement Paramete
222. ey are defined the data blocks can be displayed by pressing SOURCE M RECEIVE N or BACK GD C Only the data in the frequency range 100 Hz 4 kHz are saved in these files since the analysis is limited to that frequency range 23 FEB 14 22 33 HC HE EC surface volunt 188 A hae ee ee eee eee ROOM CATA UTIEL Hote BACK GAD SPL eras Moai Taura ur a hy wa GEIS ms wT Te San ET OBA ARA ad nd eo LIHEAR SIHGLE lt Dual HE i RESET 23 FEE 98 15 3511 685 rbd ee ie 21 eae eee A 3 Channel 1 S z HORMAL 20 0008 SB d O 4B A lel sss BIFF Ph 55 3 Sn Ta ai TACH 6 a SPEED Ba 20t RE MEE lili Re 1 ed crerR DMS s r may A E SOURCE RECEIVE BACK GD CLR BS KET X 29 Select the standards organization whose standards you wish to follow for the determination of the airborne sound trans mission parameters by pressing either ASTM I or ISO J For this exercise use the American Standard ASTM I 30 Now you have a choice of looking at Noise Reduction NR A Normalized Noise Reduction NNR B Transmission Loss TL C and Field Transmission Loss FTL D Now assuming the RT60 table is full of RT60 values taken in the receiving room all the pieces are in place Impact sound isolation is a measure of sound generated in a room resulting from repeated impacts is Footsteps on the floor of the room above In practice a standardized tapping machine is utilize
223. facing into the room Next put the microphone on a tripod in the room Turn on the pink noise generator of the RTA 15 To enable the noise generator first press SIG GEN J or NOISE J from the System menu mE 18 89 44 Chanls SLM A STANDRD CROSS INTENS Y UNITS FILTER CLASS SPL 140 r s 9 A A er HORAE a ce 97 N RRR e R 9 9 MT R EUM A dc AC we OE als UN LIHEHE SIHGLE zi 2 Em Dual LIHEHE 28Hz 28k Hz RESET 23 FEB 98 16 87 64 B6 EA a Cad tint e TOD E o cda B 018 2 e A Oat O RE E AA cae FILTER 14 z5 A Hz L K E Channel 1 EE z e HE eB E dd aa dd DIFF Ph 65 9 lt ne 6 85 BEN TACH 6 6 SPEED Bg d D dotted_ crar ROOMS IHFUT clock COLOR MLS FILES RESETS Pink noise is better to use for this type of testing since it provides constant energy for all of the 1 3 octave frequency bands 16 Press PINK J to select pink noise mE 16 11 66 OM OFF OH FUM OFF RUM ATT ATT SPL 140 A a a LIHEHFE STHGLE M Dual HE RESET 23 FEB 98 105075 Qd BB K R AO N R E T a 0717002772121 a a AAA FILTER 14 zh Q Hz L 3 KE Channel 1 ae Z Pale a r 68 Nvv NS A DIFF Ph 65 9 Sn R 6 85 REM TACH a8 8 SPEED 4 4 25 46 Hz A dotted crsr ROOMS SINE PINK WHITE PULSE DELAY 9 25 2900B TRAINING MANUAL 17 Turn the noise generator on by pressing ON A 23 FEB 16 11 66 OFF OH FUM OFF RUM ATT ATT 126 gt O SFL 146 r K N RR NR R RR R N RR RR NN NR RR RR R NR RR NN NR R R R
224. floppy is attached the analyzer will display a message indicating that no floppy drive was found HS OCT 15 51 20 create FECORDS T disk T Format Memoria Used iraz Disk Used Disk Free Hemor Free CATE IME SIZE MEMORY 7 delete rename mem delete rename Press the create A key a OCT 15 51 26 create RECORDS T disk t Format Menor 2a create R Disk Used Hemor Free 220834 Disk Free Ee OOOO DIE DATE TIME HAME CATE TIME SIZE MEMORY 7 delete rename mem delete rename 2900B TRAINING MANUAL 1 20 EXIT 3 Enter the desired new file name for this example use the name PLANT by pressing the alpha keys appearing on the display 4d OCT 16 14 76 A E C D E F G H Hemor Used 66516 Disk Used Hemor Free 193200 Disk Free ENOS TIME HAME DATE DATE TIME MEMORY a F Press the EXIT key when finished entering file name The file name PLANT will appear on the left side of the display with the associated date time and size a OCT 15 54 18 create FECORDS disk T Format Memoria Used Disk Used Hemor Free 2545 Disk Free MEMORY gt pIS MAME CATE TIME SIZE HAME DATE TIME SIZE amp l PL IW LUC MEMORY 7 delete rename men delete rename After creating a few files you may select which of these files you wish to use to store your data into To do this use the T C or 4 K arrow keys to highlight the file PLANT and press the EXIT key to leav
225. g a speaker in one of the rooms produc ing noise in that room and making the measurement in the adjoining room Three measurements need to be made to accom plish this type of measurement A 1 3 octave band sound pres sure measurement in the source room a 1 3 octave band measurement in the receiving room and an RT60 data measured in the receiving room Following is a procedure to determine the Transmission Loss and STC of a partition wall between two adjoining rooms You will use the RT60 data that was just acquired as the receiving 9 21 2900B TRAINING MANUAL room RT60 All that needs to be done at this point is a SPL mea surement in a source room and one in a receiving room Setting Up the RTA for Sound Transmission Loss Measurements 1 SCREEN SYSTEM 2 EXIT EN 5 EXIT Press SYSTEM STANDRD C to get back to the SYSTEM menu Then EXIT to the Main menu Press AUTOSTR P to get back to the Autostore menu ci lr 4d4d z3 NORMAL Les HIH HAR SEL DISPLAY nate DETECTE Hate SPL WEFAGED ai cr T LIHEHE FEFEAT HL DG bT L dE Inrut 1 LIMEAR zBHz zkbkHz RESET BS OCT 94 5 Sd 5b EEUU UII FILTER 37 5 Ell Hz LS Channel 1 of 1 vsTIME d 52 1 A 65 5 dt 2 2 02 2 3 3 5 O A FHONS a TACH B E SFEED B El z BSH Hz Hl HE Hz brec G ROOMS ROOMS usEPM STHT Mx SrFec F TRIG SETUF FILES MB E Turn off the Autostore option by pressing OFF A se gnr E se OFF b9TIME delta endstor note Hotes
226. ging 1 33 C Calculations statistics and En 10 1 Calibration 2 2 on a reference signal 2 4 on a transducer sensitivity value 2 5 Clock setting 2 27 Color Monitor activation of 2 28 D Detectors selection of 1 10 DETECTR 1 10 Dig Wet 1 7 2 27 98 Index Display weighting 1 5 F File 1 18 Files creating a 1 19 deleting a 1 22 recalling a stored record 1 23 renaming a 1 21 transferring disk files to analyzer memory 1 26 transferring to a disk 1 24 Filters FFT 2 7 Fractional Octave 2 5 Octave 2 5 I O Communications 2 10 I O port control 2 12 INTENSITY 2 2 L Leq 1 4 Linear Scale 3 3 Ln and Statistics Calculations 10 1 Logarithmic Scale 3 3 M Main Menu 1 4 Max 1 4 Max Spec 1 4 Min 1 4 Modal Analysis definition of 11 1 setting up the Model 2900B 11 16 Modes of operation 2 1 Multi display 1 6 Noise Generator Option 10 2 14 Normal 1 4 Note 1 9 Index 1 O Order Tracking 13 1 R Reference Spectrum defining 3 1 Resets 2 30 Room Acoustics airborne sound transmission loss measurements 9 27 impact sound isolation 9 34 Noise Ratings 9 35 NC 9 35 NR 9 36 RC 9 36 sound decay measurements 9 2 sound transmission loss measurements 9 21 S Scale linear 3 3 logarithmic 3 3 SEL 1 4 Setup analyzer 1 2 Setups storage and recall 1 15 Signal Generator Option 11 2 15 SLM A 2 1 STANDRD 2 1 Statistics and Ln Calculations 10 1 T Triggering 1 12 frequency domain 1 12 Waterfall autostore 1 31
227. gned to help you become familiar with your ana lyzer and it s capabilities Topics that will be covered range from basic operations to advanced system setups for complex mea surements It is not intended to replace but to use in conjunction with the operators manual received with the analyzer The fol lowing graphic identifies the softkeys and hardkeys used in the keyboard operation of the LD 2900B Sb Hz 714 HEkH 00s usREPM STHT Mx Spec 1 1 2900B TRAINING MANUAL BOLD words BOLD A words Analyzer Setup Throughout this manual the following conventions will be used to denote the keyboard operation of the LD 2900B Represent a HARDKEY function The HARDKEYS are the keys permanently labeled on the analyzer keyboard i e ON EXIT R S Represent a SOFTKEY function where Bold represents the text that appears either on the top or the bottom of the LCD display and can change depending upon which menu you have selected and A identifies the key associated with the function OFF ON SCREEN SYSTEM EXIT 1 2 1 Attach the microphone preamp or whatever transducer you may have to the analyzer 2 Turn the analyzer on by pressing the ON key located on the upper left of the keyboard 3 Press the SYSTEM hardkey 4 Press the INPUT K key EE 2 63 59 Chanls SLM A STAHDED CROSS IHTEHSY UNITS FILTER CLASS E SPL EB ca I6 r GREER A e A MN al do a A E Seams BTR R E A Jay As R E ome EXF HEHT T D
228. h an associated name The DEFAULT I key is a default setup delivered from the factory and can not be modified B3 oe 15 35 56 name R SETIUF STORE B00T note i SPL 14 5568 TH E Et hes wih Serle Gy Rin fe 2h fam ger RR AN EXPOWEWT IAL 1 A Dual LIHEBR 2B8Hz 2B8kHz STOP AS OCT 94 15 38 42 5B w L ee de ade MR A ere Bde 79 Se ce is EA R R de ae de a R RT a ete ci Hee a ux FILTER H 1 ME Hz Leo Channel 1 of 2 NORMAL i g B 66 2 3B L MP A 2 lt PHONS BZ 3 Cot b TACH H a SPEED B amp Shik He J TEL HEH H rio Er IHITIHL DEFAULT undef Under under undet undef under Under Press the name B key to assign a name to one of the undef sofkeys that will be used to store the analyzer setup B3 OCT 15 48 35 name k SETUP STORE B00T note gT 1554835 mame R SETUP STOR i SPL P 5564 TH PEN A E E O ee EXPONENTIAL Dual LIHEHE 28s zHkHz i STOP 63 OCT 94 15 38 42 54 ED A IIMI ux FILTER H 1 NE Hz Leo Channel 1 of 2 NORMAL i g B 66 2 3H L A EMPTUM Ir En PHONS BZ 3 ERE TACH 6 6 SPEED B amp x H H Hz A ek HZ dotted crsr IHITIHL DEFAULT undef Under under undet under Under Under You will be prompted on the bottom of the screen to select one of the softkeys J P B3 SSL 15 41 13 f SFL 14 5588 re Scat dia SBE BS er A IA E Mie ade Ges A fem EE AA e 4a ade dey Bu fei A Aa te TRY APR feria ul fay Sook en EXPONENT
229. his file 5 Select INTENSY E to activate the Acoustic Intensity analy U sis measurement option E Bx a 21 18 19 Chanls l SLM A l STRHDRED CROSS UNITS FILTER CLASS SPL T S858 146 a EE A T1 EXF HEHT HL 18 Dual LIHEHF 28Hz 1BkHz STOP 12 JAH 93 21 65 30 ai Ck ox o ow xw uo ooo o ooo ooo xo Romo oom OX ROX moo o ox ox FILTER 24 z756 Hz LS Se aa 1 E po Me BB dee eR NOS e eee DIFF Phzi1B1 6 Sn 72 Bz REM TACH BH SPEED B d Z S Z x dotted crsr AITEST 1 0 SIG GEM INPUT clock COLOR MLS FILES RESETS 12 deg 21 11 88 SChanls SLI HH STRHDRD CROSS IHTEHS UNITS FILTER CLASS i dBr m g aaa SH KK ae RR RN RR K K RA AS EXF HEHT T DL 1 78 i Dual LINEAR 28Hz 18kHz i RESET 12 JAN 92 21 16 44 10 FILTER 24 2580 Hz L 3 DE seii dz 1g amm DH sgg ERE re B 19 44dB E JOB_ REM i PART a E AA s EGRE gas EE EE ec icu RR AAE E Ge O Ede co a AFEA 25 8 Hz 246 Hz 14 Bk HZ A ranae 3 HITEST 1 0 SIG GEM INPUT clock COLOR MLS FILES RESETS 6 Press EXIT to leave the SYSTEM menu and enter the Acous EXIT tic Intensity display menu 12 20 2900B TRAINING MANUAL 12 Ta 21 11 37 POWER INTHSTY QUALITY SPL F UELOC DISPLAY note DETELCTFE erm B BEE SH La ae X N EELS SRA E Ae Ta A Sues TOR Od S EXF HEHT T DL 1 78 i Dual LIMEHR 258Hz l8kHz i RESET 12 JAW 32 21 18 16 FILTER 24 250 Hz LS Il wr INTENSITY i de 13 0mm SO oes pee ena EA sed l A Ra Fal SW a i Aoc cec SES BT 19 441dE 61 09002 REM i
230. hmic scale to a linear scale 1 Press the SHIFT hardkey to enter the shift menu SHIFT 2 Press the Y AXIS B key to change the y axis eem 24114133 AKIS WV HRIS JU SCALE U O FSET H SCALE H OFSET SYSINFO SPL 1 2258 a MI O AO NR NN R NN RR NN N N NNN NR NR RRR ea N N EXPOHENTIAL 1 48 Dual LINEAR 28Hz 28kHz SIDP 23 FEB 98 20 13 23 TA E REEERE EE a O NN FILTER 14 25 A Hz Les Channel 1 of 2 HORMAL 45 2 B 81 7 cag MN o DEDISTI DIFF Pbs Ba 2 Ens 209 DE REM TACH 8 8 SPEED 8 8 RAS r A RR a H Hz GA Hz HB kHz dotted crar ponFus McSTOP McWwAIT McREPT McSTART SameREF SetREF usREF The following menu appears SE 21 48 41 LIHM LIM LOG LOG LIM LOG SQU LOG Hote TEST 1 1 4588 EXPONENTIAL 1 8 Dual LINEAR 28Hz 28kHz ESET 16 FEE 98 28 43 25 o 1 of z Hcc FREE Ph 66 4 Sn 6 28 TACH 8 8 SPEED 6 4 dotted crar LIN LIN A Changes Y axis to a linear scale and cursor reads out linear LOG LOG B Changes Y axis to a log gradations and cursor reads out log 3 3 2900B TRAINING MANUAL LIN LOG C SQU LOG D Changes Y axis to a linear scale and cursor reads out log Changes Y axis to squared linear gradations and cursor reads out log useful for display of power spectral density Changing the Vertical and Horizontal Zoom V SCALE C V OFSET D H SCALE E H OFSET F To change the scaling and offset of the display select one of the following keys as 2114133 s AsIS
231. hones hardware to fix the microphones in the proper ori entation signal conditioning and microphone polarization volt age The microphones are kept at a fix distance apart by means of a spacer Typical microphone orientation is face to face The probe is directional A signal in the front of the probe will register as positive intensity while a signal at the back of the probe yields negative intensity A signal at 90 degrees will result in zero intensity 12 8 2900B TRAINING MANUAL Intensity Probe Spacer Selection The probe spacer and the microphone diameter will determine the frequency range for the intensity measurement LT LT CC A n a i n a n a A a a a a a al n a Mal n n HOCH CC CC COO CCS CG Ep I d S sq EE CO AAA A AAA AA CAC ACTA C O PACA PACO O DB 0 0 P rur a R4 0 IE DoT a DENDO eke CS RICA DICEN TO EN ua and AAA nne eh 01 DL 1 AAA ATLAS Ine teme ite th te ASAS A AAA A A NR polo is e MAA te G tc ted S td te Eni puce Hz 125 250 1 25K 5K 10K for accuracy of 1 dB Large spacer large microphone diameter for large wavelengths Small spacer small microphone diameter for short wavelengths Spacer Errors High Frequency Underestimation at high frequency EID LL 0 WI l RIEN D dB 4 a 6 12 9 2900B TRAINING MANUAL Intensity Probe Directivity Pattern e Off axis measurements will result in me
232. i Dual LIMEHR 258Hz l8kHz i RESET 12 JAH_99 21 15 49 19 FILTER 24 256 Hz L S DM gt gt isi auis l d 19 44 SH I p RP SUPR EUR A Sp Heg lobt pede cac DB ae dE J i HAm REM i PART FRONT ag amp o e AR 25 8 Hz 28 Hz 1684 kHz E A ranae 38 RITEST I J E L H H 0 P 7 After you enter the area name you will be prompted to enter the area in square meters of the test area Type in this value and then press EXIT to enter this value Dual LINEAR z8Hz 18kHz RESET 12 JAN 98 21 15 95 18 FILTER 24 258 Hz D73 pD isi auis d 19 32 SH p qeu andes acetone O moved m qt PO 201 bape l JOB TEST REM PART FRONT at K uo da a uias ridi E ge oria a i n EXAM AGE IMEEM HEEH F IFHBMT1 25 8 Hz 246 Hz 1684 kHz A ranae 38 RITEST Selecting a Linear Detector RESET R S Prior to performing a measurement adjust the input range of the 2900B so that it is optimized for the test that you are per forming To do this first make sure that your test item is on and is generating noise 1 Then press R S to begin a measurement Adjust the input range of the 2900B using the up and down arrow hard keys 12 23 2900B TRAINING MANUAL 2 The proper input range would be at the range setting one or two steps above the setting where the 2900B overloads Start ing from a high range step down using the down arrow key the range one 10 dB increment at a time until OVER appears on the screen Then arrow up o
233. i PU ute Te eH bb pausa 10 5 R callins D1 ACES ar a 10 5 Recalling a Statistics KT e iia ida 10 5 Mersing Statistics Tables dali 10 6 Chapter 11 Modal Analysis sccsssssscsssssscesessssesnssesesssesesssssennesesens 11 1 What is Modal Analysis iiti orit enit eodeni 11 1 Dynamic ANUN SIS ot 11 2 Moda Models na En fs 11 2 WC 1S AMOO sisi use d erac Rede recente secteensmenitosnen ness 11 2 The Frequency Response Function FRF ssss 11 3 Modal Parameters from ERES coins 11 3 Mn Use Modal ASIS aa tud Rd ee Cup dati cono teda au Papae vara 11 4 Making Modal Measurements sss sese ee eee 11 5 Excitation Techtuq es eiii vectaswtldacaxies 11 5 impact Haiti 11 5 Time Domain and Frequency Domain Signals 11 6 Impact Hammers Frequency Range esse ee eee eee 11 7 impact Hammer TS al odas 11 7 Impact Hammers Double HIS sese 11 8 Impact Hammers Off Axis Ella 11 8 Impact Hammers Averaging assez cs zg avas tsz zs do 3 oaae vocnt 11 9 Exponential Windowing occccccccccnnnnnnoncnnnnnnnonnnnnonnnonnnnnnononannnnnss 11 9 Leakage Why We Use Windows sese eee 11 11 Snake Ex aO rc TRE 11 11 Chapter 12 2900 TRAINING MANUAL Shaker Test SCHCMIAUC bee entia ep Rea dao de tese Aia uns 11 12 Shaker Excitation FUNCHIONS oocccccccccnnnnnnocnnnnnnnnnnnonononnnannnnnnos 11 12 Attaching ACCeleromiefebs e ere ERU Ren E I ud 11 13 Test Setup Establishing a Measurement Grid
234. id EXPONENT L HL 1 8 Ineut 1 LINERE 1Hz 1i kHz RESET 18 MAR 94 17 87 51 FREQ 8886Hz HSRA Channel 1 of 1 HORMAL d 15 3 B 12 8 TACH 6 8 SPEED 4 4 dotted crsr undet Under Under 4 You will now see a number of alpha character choices above V and below the display Since we will be measuring vibration F in G s type in the letter G G followed by 5 presses of the SPACE key to clear the remaining characters You can also press SHIFT and then CLEAR to clear the unit entry field then press the letter G G 18 MBR 17 08 45 A E C D E F O H Enter unit n SPL B Baa ae LA deli ws eei Um coo R A Tel a m Um LY E UR p E R m TE de e oum Jw ow Ow od e E m m RE ae Re EXPONENTIAL 18 Input 1 LINEAR iHz 1BkHz RESET 18 MAR 94 17 87 51 FREG S BBaaHz Hann Channel 1 of 1 NORMAL d 15 3 Ee 17 8 e LOC TACH H 6 SPEED B El BA HAHA zD UM 1 2506 0050 Z A dotted crar UIBi I J E L IN H a F 5 Press EXIT to enter this unit name Select G K to enable the unit label G K ine 03 11 55 SLOPE rame SAME E UHITS Hoise F ml cal U cal level SPL B midi EXPONENT L HL 1 2 Ineut 1 LINERE 1Hz 1i kHz RESET 15 APR 94 09 11 35 x ma ARBBHz HSRA Channel 1 of 1 HORMAL d 15 3 B 12 8 TACH 6 8 SPEED 4 4 dotted crsr under Under Under Notice that the unit label G appears in the right portion of the display Note that the unit label G has been assigned to the K key ats 17 12 53 SLOFE
235. ince the RPM of the tachometer signal is below 500 nothing appears on the display although you can see the trace labels on the left side Note the current RPM reading from the tachometer is displayed on the lower right side of the display 15 10 46 SLOPE alevel TAGBARS s SFHH LIDEO pH LS note WIDTH SOURCE IS TACH IHPUT ur uL mr EP A a HE C FREQUENCY Kk Kk Jl Kek ek GOAS L3 co U E A C 55 5 crs FEH CHAHHE FE RESET R S CURSOR STORE 2900B TRAINING MANUAL Now as you sweep up the running speed of the de motor you can watch as the selected frequencies change in ampli tude as you run up from 500 RPM to 3000 RPM 16 a 18 15 69 SLOPE elenel TAGERES SPAM VIDEO pH LS note WIDTH Mudo uS dci rata line Gaetan at SPUR r See de mH THEUT 229 20006 SEE ap S Sas SB ia io dure LIRE a RIC EXPONENTIAL 15d Input 1 LIHEBR 1Hz 146kHz RUH 16 OCT 94 18 14 39 Da a o iT FEH LELEL C FREQUENCY k l 37 8 1 12 506 2 B2 36 1 1 25 AEE A AAA 3 AS Boar 1 3r RHH d O4 23 2 1 76 pac B B5 23 9 1 62 388 pO ee ee ee ee 5 HE 43 1 SHH Bad a S666 RPM 159 crsr _ 474 DCMOTOR STATUS HIDE TACHSET B ORDER CAL PEH CHAHHEL FREL When the speed of the motor reaches 3000 RPM press R S to halt the measurement The completed measurement appears below 16 OCT 18 16 87 SLOPE level TAGBARS X SPAN UIDED X AXIS note WIDTH gt i COURCE IS TACH INPUT G 64 1666 EXPOHEHTIAL 1 64 J Input 1 LINEAR 1Hz
236. ined to calibrate using the shaker calibrator entering 32 2 ft s in the level field Now the RTA is ready to analyze vibration signals and dis play the data in calibrated velocity units 13 Press R S to gather velocity data from your vibrating struc ture az sal 4142141 SLOPE name SAME R UMI TS Moise F mi cal U cal level B B SPEED B B Epi E DUS El solid crzr IHITIHL dE HL SPL 5 FTS undef under under Under 2900B TRAINING MANUAL 14 The last task that we need to accomplish is to save the vibra SCREEN A tion measurement setup so that we can avoid having to SYSTEM N reconfigure the analyzer should we wish to make additional vibration measurements in the future Press SYSTEM and then SETUP N to enter the SETUP menu 15 From within the SETUP menu press name B so that we can E assign a name or label to this setup B3 sa 64144153 R SETIUF STORE gt BOOT note ic 20 9084 LINEAR SINGLE 24 9084 Input 1 LINEAR 1Hz 1GkHz STOP m3 JON 98 06 41 13 FREQ BB AGGGH2 ASAA Channel 1 of 1 NORMAL s 46 3 E 34 9 TACH 8 8 SPEED 4 4 Li LIP solid crar DEFAULT MODAL Under undef undef under undet 16 Next press undef J This will select the K softkey within the SETUP menu as the key to which our vibration setup is K stored 43 JAN gg 46 08 a i FT S Hn 20 0900 56 A RO A N N 8 N LINEAR INGLE zu e ARB Input 1 LIHEHR 1Hz 16kHz STOP mx JAH 93 pB 41 12 H A ii ES Sas T e E DAR A
237. ing the dc motor run up The orders that are currently displayed are shown on the right of the display orders 1 through 6 Notice also that each of the 6 traces are labeled on the display 13 25 2900B TRAINING MANUAL 6 Press STORE to archive the measurement to the DCMOTOR 8 file STORE 16 OCT 18 47 21 SLOPE level TAGBARS X SPAH VIDED AXIS pote WIDTH Ae A tis Sa exp rc acd E STORE usEFI Trace z SOURCE 15 TACH INPUT pr 3 187 56088 2H a a a ARA ee as ekg E A EXPOHEHTIAL 1 car la Une E a Inrut 1 LINEAR 1Hz 18kHz RR OF 16 OCT 94 18 46 30 4B lt PEN LEUEL C ORDER f K l Ail l 61 004 vw TL 2 Bz 6 4 Az BAA S ea H a a a a RR aa fe 3 Hi 17 6 1 B3 aad 4 Bj 37 4 l B4 HAA Loc 5 B5 34 4 1 B5 ana amp Ow x ELO EC LOEO A Re DR OCCORRE UR OS AA dec e RD OE RP UR n Do DG 3H 4 1 DG ARR Saa 30606 RPM 84i crsr 878 DCHMOTOR STATUS HIDE TACHSET E FREG CAL FEM CHANHEL ORDER Notice the message STORE vsRPM Trace 2 appears at the top right corner of the display indicating that the data has been saved 13 26 Symbols Chanls 2 1 Numerics 3200RC remote control 2 11 A Acoustic Intensity definition 12 1 setup of 2900B 12 12 Analog Input Filters 2 23 Autostore block averaging spectra 1 33 by time 1 27 byTACH 13 1 display of waterfall 1 31 recalling 1 29 vsRPM 13 16 B Basic Acoustics Acoustics basics 4 1 Battery check status 3 4 baud rate 2 10 Beeper Control 2 13 Block Avera
238. is capable of calculating Ln values between 1 and 99 CURSOR RESET R S RESET R S 10 2900B TRAINING MANUAL C Press the Cursor hardkey to re assign Ln control of the cursor to the right and left arrow keys Press the R S hardkey to begin the analysis The state of the analyzer will change to RUN which is indicated just above PEN on the right side of the screen You will not see any update of the display until either the analysis is stopped by pressing the R S hardkey or by press ing the REDRAW H key Press the R S hardkey to stop the analysis The display will update with the Ln values and curves 13 BEP Ba 41 29 ON OFF S Time dE SPHH E STAT HIDE CLEAR REDREH 11 6868 15 ES z Hz zBkHz 106 L H STAT FEB 98 08 39 04 56 n i4 25 6 Hz 1 n Lmax wal aoe Lmin 36 6A K LEG 6 4 56 5 MEAN 49 8 FEM 45 6 STD ar a 38 ZUNDER 76 4 Ln cursor CHHHHEL Press the horizontal keys to move the cursor to the desired frequency of interest Note that as you move the cursor through the different frequencies the Ln values change 19 ERP 62 42 48 ON OFF S Time dB SFHH E STAT HIDE CLEAR REDRAW These values are correlated to the amplitude of the trace drawn on the display 10 3 2900B TRAINING MANUAL Hiding a trace 1 Select the desired trace to hide by pressing the trace number via the numeric keypad 2 Press the HIDE F key An asterisk will appear next to V the trace number indic
239. l ST E ar RR N 1720020 E C Pe A a e EXPOHEHTIAL 1 64 bTACH Inrut 1 LIMNERE 1Hz 1 kHz RESET 15 OCT 94 28 11 27 44 CP FEEG Had ARARAH agen Channel 1 of 1 H ORMHL d 95 2 A UNE l l TACH 8 46 SPEED B 96 HAHA Z o0mM 1 tama Ba dotted crar IHITIHL Qs 5 2900B TRAINING MANUAL t input toggles between the various options for the TACH INPUT The choices are CH1 CH2 and jack Press t input E to toggle through the choices until jack is selected 15 OCT zi1 953 33 L scale L sran Lenin t amaxf t intu cal SLOFE AWG OCT 21353133 t scale t sran tenin t amax 3 A 0000 2p ere ee ema ee Re cae Serna Mat ca a A a ar o TT fe a ont amy fant ide a o tada A T E EXPOWEWT IAL 1 5d bTACH Ineut 1 LINEAR 1Hz 1i kHz FESET 15 OCT 94 28 11 27 44 Eaa A A usc 2c FREQ Bi HnammmHz H4HH Channel 1 of 1 HORMAL d 95 2 E 71 9 ED C Gal vat RT T R Gey aoa Get st el Wat N A N da T aM R E R Segoe a TACH 6 6 SPEED B Bn GREE 00m 1 DEBE 02006 dotted crar IHITIHL scale s sran s amin s a4max EHDHE f RADAR m x cal is a feature that allows you to calibrate a tachometer from a known reference You feed a known tachometer sig nal into the TACH INPUT of the 2900 For example a signal at 1000 RPM exactly is fed into the 2900 Within the x cal field the 1000 RPM factor is entered as a reference signal The 2900 would then be calibrated for this tachometer You will not use this feature for
240. l1B8kHz Q STOP 16 OCT 94 18 15 44 PEH LEWEL C FREGUEMCY k l 32 3 1 12 506 2 BH2 356 9 1 23 AEE 3 B3 1 5 1 ore Jee 464 3 3 1 SD pac B B5 8 4 1 62 700 6 g 29 4 1 266 262 Ja KISS RPM 364i crsr r26 PCMOTOR STATUS HIDE TACHSET B ORDER CAL PEH CHAHHEL FRED As with the vsRPM autostore test notice that the display is currently viewing 6 different frequencies from the acceler ometer as they changed in amplitude during the dc motor run up The frequencies that are currently displayed are shown on the right of the display Notice also that each of the 6 traces are labeled on the display Press CURSOR to activate the dotted cursor Push the right arrow hardkey to move the cursor along the RPM axis The amplitudes of the frequencies at each RPM are shown at the right When you are finished viewing the data press STORE to store the measurement record into the DCMOTOR file Notice the message STORE vsRPM Trace 1 appears at the top right corner of the display indicating that the data have been archived 16 OCT 18 16 31 SLOPE level TAHGBARS X SPAN UIDEO rode P E J nate WIDTH E OURE IS TACH INPUT m EXPOMENTIAL 1 64 A ERR iHz 18kHz L H 16 OCT 94 18 15 44 E L daas CE Mi Adri Lomo Be a E T The 111 ct CCT A lic CT Ea CeO _ m OLA JOA RE ian Hene HCH m m i a CR Tr n l LA LA pajaro ia lili yy am Sa zm I Al e Co z Lal B S B B B B S S Ec c za ms
241. lay to a flat response No Weighting Adds an A Weighting curve to the displayed spectrum Adds a C weighting curve to the displayed spectrum Adds a User defined weighting curve to the displayed spectrum Adds a weighting curve that is the inverse of the A weighting curve to the displayed spectrum negative Adds a weighting curve that is the inverse of the C weighting curve to the displayed spectrum negative Adds a weighting curve that is the inverse of the User defined curve to the displayed spectrum negative 1 7 2900B TRAINING MANUAL 1 8 EXIT Zw Free A Zw Diff B 5 Select Zw Free A or Zw Diff B to apply Zwicker loudness function to the displayed spectrum AS on 15 65 13 141 1 43 SUM SETUSER note Applies Zwicker free field loudness function to the displayed spectrum Applies Zwicker Diffuse loudness function to the displayed spectrum When in the standard analysis mode with 1 3 octave filtering the Loudness corresponding to ISO Recommendation R523 Method B sometimes referred to as Zwicker loudness after the researcher who developed the method is calculated and dis played on the lower right of the screen There are two forms of this loudness which correspond to measurements made in dif fuse acoustic fields where energy is from all directions such as inside a reflective space and measurements made in the free field where the sound is radiated without reflection from a sin gle acoustic
242. lock COLOR SETUP FILES FESETS h ke N E 5 2900B TRAINING MANUAL You will use a 400 line FFT for this test Press 400line K to establish this frequency resolution choice ur i oo m o eee a ee ee no Her SPL B ABBE eh Seay Mn a AA A tke o e Ba AL R AA A A ar RRR RL a K Ae Gat TE EXPOWEWT IAL 1 A Ineut 1 LINEAR 2B8Hz 2BkHz RESET 15 OCT 94 15 47 82 48 SR E A E eee a N RRR ce ede A O I an R e FILTER 14 25 Hz Le 3 Channel 1 of 1 NORMAL d A 34 9 zal T PHONS EB 3 LOC BE IIT TREH B a PEED B 6 INITIAL Z 1001ine 2001 ine 4001 ine saa ine FFTZOOM WINGO pasted diu Choose an FFT window You will use a Hanning window for this measurement If Hanning is not already enabled press WINDOWJN to enter the Window selection menu E RC I ro E Fon enne SPL B ABBA eh Eie RRR et JR ee Ee ums dec A de cos EI NR OE ums A LR lt de deg us RC a RR 9 EXPONENTIAL 18 Ineut 1 LINEAR 2B8Hz 2BkHz RESET 15 OCT 94 15 53 43 ae CX TM a TET PEMEX E ERE HA ARRAHZ H4HH Channel 1 of 1 NORMAL E d 15 3 T ze o DE T TREH 8 8 PEED a 8 INITIAL 1991 1 ne 2601 106 4Baline 88Gline FFTZOOM snow pase Ba Mid Press HANNING B to activate the Hanning window 15 ee ir B 9 7 RECT l D FLAT l ZERUFRD IMPACT ExP 2 ExP 4 ExP 6 SPL B ABBA BG eR RR Ge RR RR RRR NR A A Me cu RRR a RS GV E GS UR A A R 8 EXPONENTIAL 1 78 Ineut 1 LINEAR 2B8Hz 2BkHz RESET 15 OCT 94 15 53 43 ae NR NAR URP ee SEDAN N on R
243. lt L Slope J Slope K 2900B TRAINING MANUAL The word TRIG will appear on the left side of the display This indicates that the trigger function is activated This type of triggering can be used with either Octave filtering or FFT B3 oa 15 26 57 r 29 SHH Hz 0206 A 5 14 6654 PAA cegcudai dei bean ba pP eM eeu ae dus EXPOHEHTIAL 1 8 Dual LIHEBR 2B8Hz z2zB8kHz STOP AS OCT 94 15 25 56 O C A FILTER H 1 15 Hz LA TRIG Channel 1 of 2 NORMAL d 16 4 f 56 5 PHONS 64 4 TACH 8 8 SPEED 0 0 Trigger MANUAL RE ARH OFF level E H Hz INITIAL SLOPE 5SL FE 2 Setup the desired trigger criteria trigger frequency and the trigger level a Press one of the following keys to setup the trigger criteria Triggering will occur whenever the level in a specified frequency band equals or exceeds the programmed value Triggering will occur whenever the level in a specified band is less than or equal to the programmed value Triggering will occur whenever the signal in a specified band has both the appropriate trigger level and has a positive slope Triggering will occur whenever the signal in a specified band has both the appropriate trigger level and has a negative slope a3 dolce 290 888 Hz 990 9 i 14 6658 TH cde KRE RRR RR Two a cS i a Ga RT a R alt Al RET N ea ea ee TRE RT ae EXPONENT IAL 1 5 ual AR ZHHz zBkHz STOP H i OCT 94 15 25 56 54 Lulu FILTER 4 1 i aud Hz L TRIG
244. min Er Al 306 306 DCMOTOR STATUS HIDE TACHSET E ORDER CAL 13 23 2900B TRAINING MANUAL Real time vsRPM Order Tracking 13 24 OW Now let s do a Real time vsRPM order analysis Change from frequency display to order display by pressing B ORDER L 16 PE 18 42 55 SLOFE alevel TAGEARS THE Pe A ARIS note WIDTH SOURCE IS TACH IHPUT 21 1466 S ia 1 64 Fut LIMEBR 1Hz 16kHz 16 OCT 94 18 E E FREB ERES ui m mom zu r Gi d ha Sp Ap nl n Turon ca LIII THAENE Cm a Lake m Z eene C OOT I Gar LAS JOA zu DCMOTOR STATUS HIDE TACHSE CAL Press YES A to answer the question ARE YOU SURE You are being scrutinized because answering yes will clear the display You will lose the data unless you have already saved it to the 2900 memory m Mil dan Io n zi m ra Er al m 16 OCT 18 43 16 YES Be F 4 ARE YOU SURE 21 1488 eere ERP UHEHT IAL 1 64 Input 1 LIHEBR 1Hz 18kHz STOP 16 OCT 94 15 42 28 W EEN LEUEL C FREQUENCY K Bi 49 8 175 500 2 B 51 6 il 55 BBB alg xo we don or oy mox won ox cl E Nono o ox ox ox ANE eo on ox onn 3 Hz 47 1 1 Ar 00A 4 B 23 8 1 5B 004 Loc 5 B5 95 7 I 52 558 amp B amp PU Xr DG 66 1 1 2564 ARR 3000 RPM 156 crsr l JB DCMOTOR The next screen will ask you to SELECT THE MAXIMUM ORDER Press 400 C 16 OCT 18 43 59 199 200 Ca ee j Pr 1 21 1488 HEAR iHz mkHz DCT 9 Bgid2iB
245. mplifier speaker system An excellent device to drive the speaker amplifier is the LD SRC20 portable pink and white random noise generator or the generator in the RTA If the RTA has the Noise Generator or Signal Generator option connect your speaker amplifier to the Source Output jack Place the speaker in a corner of the room facing the center of the room 1 To enable the signal generator press SIG GEN J from the Z System menu J 25 FEB 12 36 58 Chanls SLM A STANDRD CROSS INTENS UNITS FILTER CLASS SPL B aaga 140 r R 0 KOR an O OORE RT R 18 A ap At Mab R EO RY nas A N ER Shag Uii N T ca cae JN cae ORR CK EXPOMENTIAL zB Dual LINEAR 28Hz 28kHz RESET 25 FEE 98 12 36 21 ag r d EE E ANO E E FILTER 14 75 8 Hz Leo Channel 1 of 2 NORMAL d 34 H 46 15 r Ws EDRR OR Ac lo R ao take RRR R M b a 8 eI Set E E E E CIFF Fh 65 A Sn 6 85 REM g TACH 8 8 SPEED 8 8 25 6 H car A Gk Az dotted crar ROOMS 1 0 SIG GEM INPUT clock COLOR MLS FILES RESETS Pink noise is better to use for this type of testing since it pro vides constant energy for all of the 1 3 octave frequency bands 2 Press PINK M to select pink noise BS OCT 12 55 15 OH OFF DH RUM OFF RUM BURST M 115 CXII OS 2 SFL B BeBe a A p c X D A RD EZF HEHT HL 1 8 InEgut 1 LIHEBR 28Hz 2B8kHz RESET 68 OCT 94 12156166 TH NR A ARRE KR R ARAR LL LL ELS FILTER 14 75 8 Hz Leo Channel 1 of 1 NORMAL d S A 34 3 PHOHS 33 6 58 LOC TACH H H SPE
246. nals that are in the presence of larger signals The rectangular window is the preferred choice when measuring transients The zeropad window should be used when doing autcorrelation and crosscorrelation measure ments The Impact and Exponential windows in the 2800B 2900are used only when one is performing impact hammer measurements as in the case when one is measuring transfer functions frequency response functions for a modal test Selecting an FFT Window 1 Press WINDOW N to enter the window selection menu ge ISL 225 dL529 1lrloct 143o0ct lona short reverse SPL B GEE at ARS p AQ I LL C XLI LL ERXF HEHT HL 18 Input 1 LINEAR 2BHz zBakHz RESET 2 JAN 99 23 38 41 70 ee ae ae RN ae W NN N RR E RRR R K N RRR K NN NR NW 052112010 FILTER 16 46 0 Hz Leo garanna lof 1 A A DIFF Ph 52 8 Sn 2 42 REM TACH a d SPEED B d E he A T eee eee ee eee l t 23 0 Hz 638 Hz ZU OkHz OFF IHITIRL 1Baline 288line 4Bbline Saline FFTZ00M BHSE Bd 2 The Hanning window is the most common choice for gen eral vibration measurements so press HANNING B tick 23144155 RECT FLAT zERD FHD IMPACT EXP 2 ERF 4 EXP SPL EB mia aii CN vM TIMI ITEM ERXF HEHT HL 178 Ineut 1 LINEAR ZEHz z BkHz FESET z JAN 928 23 43 48 ro MN T RR A R FREQ HE E z5HBadHz HSHH Channel 1 of 1 HORMAL g 15 3 B 12 5 REM TACH HLH SPEED B El Bii E S EH dotted crar INITIAL 7 5 2900B TRAINING MANUAL 3
247. nd stop automatically when the end store time has been reached 2900B TRAINING MANUAL 1 37 2900B TRAINING MANUAL 1 38 System Menu To access the System menu from the Main menu press the SYS TEM hardkey located on the left side of the analyzer In this menu you can select the desired mode of operation perform a calibration select the desired filter band width I O communi cations or change the input filters Operation Modes There are five basic modes of operation of the analyzer To select the desired mode press one of the following keys E ES 16 65 11 V Chanls SLM tA STHHDRED CROSS INTENS LINITS FILTER CLASS SPL B ama FL EXPOHEMTIAL 148 Dual LINEAR ZzBHz zBkHz RESET 19 FEB 93 beo TH A Se oe E UA ace VR TR de eode Si ANA des NNT AA qos does de dorm arc OA ee cet FILTER 14 25 4 Hz A one 1 of 2 NORMAL SBE oe eee ee a eee eee DIFF Ph 52 8 Zn 2 43 REM TACH B SPEED B Lok ee eee ee ee ee ee el Etat ed inr ho EH ERE CS l I 25 6 Hz Bon Hz 24 BkHz datted crar INITIAL 1 0 SIG GEH INPUT clock COLOR MLS FILES RESETS Chanls A This key toggles between channel 1 and channel 2 operations SLM A B This key activates the SLM mode of the analyzer You may also activate the SLM mode from the SLM hardkey on the analyzer This mode of operation is discussed in detail later in the manual STANDRD C This key places the analyzer in the Standard Analysis mode con sisting of six different
248. nder Under undet under Under 2900B TRAINING MANUAL 13 You will assign this label to one of the undef keys Press undef K or another undef key if K is already assigned to K another label 15 OCT 19 34 13 ng M DM I oben eer BAe eee SU ene Sie eve ae Gu aceon ei FUSH UNITS TO WAME SPL B midi eh uix A A cone Je SR WU RE TNI ewe a Je Arc T D TEE n AT GR URS a Rec Re RR SED RTT E E OR EXPOWEWT IAL 18 Ineut 1 LINEAR 28Hz 26kHz RESET 15 OCT 94 19 34 03 ae rub deer xac hu LEUR CES e SUV Me e EU sah Sar p cup Yala EP US Y Sie a 2 a ut SP ae Thes Te DS 8 Se de dat cus db ae ae E FREQ BA ARRAHZ H4HH Channel 1 of 1 HORMAL d 15 3 B 9 8 Loc i TACH 8 8 SPEED 4 4 Ei AAAA Z 00m 1 E md dotted crsr INITIAL under undef uder o under 14 Type in G G as the units name W 15 OCT 19 35 25 A E t D E F 8 H 6 Su u WE a K AAN D OEC UE de C RC OO N X Deo dn D wie S Mire home UR tee 09 Enter as nane 8 SPL 0000 rr ELLE LLL LLL LLL LC ESPOMENTIAL 1 2 Ineut 1 LINEAR 28Hz 26kHz FESET 15 OCT 94 19 34 62 ae A IET ae Sle A ae epi a R TITIO TITIO FREQ He HHHHHZ H4HH Channel 1 of 1 HORMAL d 15 3 E Loc l I TACH 6 6 SPEED Bg d Bl m zD UM 1 cama a dotted crar IHITIHL I J E L d H a F 15 Press EXIT to enter this new label 15 y 19 36 69 SLOPE name SAME k UHITS Hoise F ml cal U cal level 16 Now select this new unit key to activate it Press G K Zz SPL B mid eh
249. ndow is a time domain window e You do not always need to use an exponential window e Exponential windows introduce artificial damping to the FRF s If you are concerned with damping values you ll need to correct for this 2900B TRAINING MANUAL No Exponential Window Exponential Window Exponential Window applied 11 10 Li JEF 11153126 A SPECT C SPECT KPEE COHER TIHE DISPLAY note CETECTR iu E gene Mus d ENSE LE E 1 ie USES isle ied EIA srn CU on mom on 3 9 o3 9 2 3 o3 c s 3 3 3 3 c 1 Bate Frequency LIE TACH B SPEER p i di BEBA Ch J Bb p 5H dolbed cra FIT EFH ELHLEH Pak ALIAS T TEIG EETLIF FILES HFLITDIETPE DISPLAY mote DETECTR ERP 10 L LU COHER TIM o T ETHGLE d in nig oon PEA pen CU ar i s s 2 3 Base Fregen DC o5 TACH 9 9 SPEE 4 0 de presa 200K L B EA dobted_crar SMEBE A TERY ELHORA PIE ALJAE T TRIG SETLF FILES HUTOSTR DISPLAY mote DETECTR M JAN 21024125 ASPECT C SPECT X FER CHER T FEAL RESPONSE SPECTRA 9 ND CMT MDC Man eta baw eee ye ade bones 1 SINGLE 4 e MEA ao at E a MEME FOR 0B 3 3 8 2 3 2 03 03 93 3 3 3 3 303 9 X 3 5 303 3 9 3 3 3 3 3 3 3 3 5 Esp Freausrnc4 TACH d a SPERE a nom i B EA wdobted crar FLTEFH ELFLEH PL R ALIAS T TRIG SETUP FILES HUTOSTR 2900B TRAINING MANUAL Leakage Why We Use Windows
250. ne or two 10 dB steps You are now range optimized 3 Press R S to stop the measurement The autorange feature of RESET the 2900B can also be used but usually more time consuming R S than the manual method 4 Set the detector for linear single averaging by first pressing X DETECTR H H 12 d BN ZA DPE 48 7 POWER l IHTHSTY QUALITY 7 SPL 7 F VELOC DISPLAY note i dBr m2 a aaaa SA S T ie ta E Jide ave hone ce a SEES LE dE EEE EA EE EXPOHENTIAL 1 48 Dual LINEAR 28Hz 18kHz i RESET 12 JAH 33 23 57 15 1H FILTER 24 z750 Hz L S AM gt gt iE 0 a 13 2mm i d 13 44 A 32 5 54 Loeb R a qu e ran aa ae AA A GAS We F lJ 1 de dB del EHE J _ TE FEM i PORTS FRONT aj LEE e wow sw d UL Dec e wo H MI ND 9 JR ane aola E A AA ges AFEA FOIHTI1 25 8 Hz 392 Hz 1B mHkHz Z A panae a HITEST Job Fart area pr L Sp meter SETUP FILES AUTOSTR 5 Then choose LIN S A Q 12 JAN 23 58 86 m LIH R EXP BT EXP BT LIM RU TIME A at uu C dBr mz g aaaa SH Se momo momon nom m m nomo n on ono m on n on m m no m mono 9 om ono mo n y n m n n n m m s n n n ERXF HEHT HL 1 8 i Dual LIHEHRE 28H2z 18kHz i RESET 12 JAW 32 23 97 19 B HREH 25 8 Hz 246 Hz 164 BkHz E A dotted crar AITEST 12 24 2900B TRAINING MANUAL 7 Entera DETECTOR TIME of some value between 20 and 60 seconds In general you will get a more accurate measure EXIT ment with a longer averaging time Press EXIT to enter this value 12 JAN 23 53 61
251. ng on Channel 2 Impact Weighting on channel 1 Exp 2 Weighting on channel 2 Impact Weighting on channel 1 Exp 4 Weighting on channel 2 Impact Weighting on channel 1 Exp 6 Weighting on channel 2 The Impact and Exponential Weighting windows are generally used for modal analysis applications 2900B TRAINING MANUAL 4 Press the BASE Bd O key to select the Full Scale Frequency Baseband 1 FEB 17 03 19 1lrloct 1 Zoct lona short reverse SPL 41 5688 TE KX NN N RR DTI A RR N a Ge N EXPOHENTIAL 1 48 Input 1 LIHEBR 285Hz zBkHz STOP 13 FEB 32 17 03 03 T c XT PEE Call ee fais RE RRR R R A SEAN TEM FREQ Aa BHARAHz Hd4HH Channel 1 of 1 HORMAL d 47 9 B 60 8 TACH 8 8 SPEED B a da Gred crear IHITIHL 166line 2960 1 1ne 468line 29601 1ne FFTZOOM WINDOW BASE Ed 5 Press one of the following keys to select the upper band edge Your selection will be identified on the lower right side of the frequency axis 13 a 17 41 56 zBkHz lBkHz Sk Hz z2 KHz SFL nu EXPOHEHTIBL Inrut 1 LINEAR zBHz z kHz B BEBE 1 8 RESET 19 FEB 38 11 66 41 B EO amp o x WoW x ECX RRR OE a EO x X X amp ow x ox X x FREQ Q HHHGHZ HSHH Channel 1 of HOF r 33 amp SE gK cy Nav stir RR RR cael MLB xc A A o dX X CUE E A Gee A O Cab ad Mave K SEINE od BEM t TACH H B SPEED B B E dotted crar FO BB IHITIA 20kHz A 20kHz upper band edge 10kHz B 10kHz
252. ng the Autostore byTach feature for this test Press AUTOSTR P to enter the autostore menu 15 DET 21 45 46 WORMAL Lea MIH HAs SEL DISPLAY nate DBETECTR G B HHHH z AAA N N EXPONENTIAL 1 64 bTACH InEgut 1 LINEAR 1Hz 16kHz RESET 15 OCT 94 29 11 27 44 E A AR a IS HnammmHz H4HH Channel 1 of 1 HORMAL d 95 2 E F1 4 6b gR KE A Cie E A R A A RR R RRR R R KR RRR R AA RCA Loc TACH H 8 SPEED Ha 24 E E A RR ED an BEE 00m __1 Eua duftted crer INITIAL ROOMS usRPH STAT Mx Spec F TRIG SETUP FILEX AUTOSTR 19 7 2900B TRAINING MANUAL 2 To activate byTACH autostore press byTACH J Z 15 SET 21 46 29 OFF ESTIME delta endstor nate J G B ABBA 2H E E fan Tah pcd TT use eS IRL HR LR R Ear ROL TE AAEE A us Genes whe Tt Mn Oe EXPOWEWT IAL 1 64 InEut 1 LIHEHR 1Hz 1BkHz RESET 15 OCT 94 28 11 27 44 SN A RT R A ORO NRT N I MEMORIES NIE v MON ene ROME AAA A NRT T PIRE FREQ DD ARRAHZ H4HH MCI lof SEE M i Loc TACH BL SPEED B B dotted crsr ILES 3 Notice that the label bTACH appear on the left side of the display You next need to configure the tachometer parame K ters for the autostore acquisition Press TACHSET K to enter the Tach parameter setup menu 15 SS 21 4r 16 OFF b4TIME delta endstor note E B BRR a AO e EU RN Mona a RE Gh e Ya DE lm N XD X RTE Rae Ro ec KTN a po Ed ae RN EXPONENTIAL 164 bTACH Input 1 LIHEHR 1Hz 14kHz RESET 15 OCT 94 28 11 27 44 RA ee ce eres Gey See c
253. note WIDTH SOURCE IS TACH IHPLIT B auda EXPOWEMT TAL 164 Ineut 1 LIHEBR 1Hz 18kHz Eve OCT 94 15 42 35 FEH EL C FREQUENCY i 56 7 1 12 588 z Hz 59 6 1 25 48 3 BHi 49 5 1 Sr Jee 4 H4 30 5 1 5B HAA B 5 27 2 1 62 26 K BE 47 6 1 264 000 3mma RPM SUB freauencu DCHOTOR STATUS HIDE TACHSET B ORDEF FEDFAL FEH CHAMHEL FEEL Post Process Order Tracking The vsRPM graphics display also allows us to view orders rather than frequencies in the amplitude vs RPM format The orders for the byTACH autostored data are calculated using the tachometer information that is appended with each of the fre quency spectra that were acquired during the autostore 13 19 2900B TRAINING MANUAL 1 r 9 Input 1 LINEAR RESET 16 OCT 94 15 42 36 FEH LEVEL C FREGBLEH 1 l 56 71 1 12 500 2 B2 59 6 1 25 888 3 Bi 43 3 1 ore 300 4 mj 38 3 1 30 mad ERER l edd DCMOTOR YH STATUS HIDE TACHSER B ORDER REDRAW PEN EHnNHEL PEE 2 The next screen will ask you to SELECT THE MAXIMUM S ORDER Press 400 C C 16 OCT 16 11 29 106 258 qa ad SELECT MAXIMUM ORDER SOURCE IS TACH INPUT a 8 8268 P bs ERF HEHTIBL Le Input 1 LINEAR 1Hz iBkHz RESET 16 OCT 94 15 42 36 PEH LEVEL C FREGLIEHC K Bl 56 71 1 12 500 2 B2 59 6 1 25 888 A A AS E E Hi 434 2 1 AT 00A 4 mj 38 38 1 30 md 2 BJ 2r 3 1 62 300 Foros mon opo 3 om or 9o 3 9 m o3 3 9 9 9 93 9 9 9o 3 9 m o3 o s m ao p o3 n as rog snos m gogo s m nor on DG 47 8 1 2564
254. ntry field 16 OCT 14 47 85 SIS SHS Basada SGG EXPOMENTIAL 164 Ineut 1 LIHEBR 1Hz 1B8kHz STOP 15 OCT 94 22 21 38 FEH LEWEL C FREGQUEMCY l 356 7 1 12 506 2 BH2 39 6 1 25 BEE 3 3 49 8 1 ore Jee d G4 36 2 1 SD pac 2 B5 27 3 1 62 290 6 B 35 7 1 To Baa 6668 RPM 286 crer Bi ans DCMOTOF The vsRPM graphics display has some interesting features First notice that the display is currently viewing 6 different frequencies from the accelerometer as they changed in amplitude during theDC motor run up The frequencies that are currently displayed are shown on the right of the display Notice also that each of the 6 traces are labeled accordingly on the left side of the display 16 14 45 56 SLOPE elevel TAGERES s SFHM WIDEO BOARS note WIDTH am 4D A TZ kek kk Ke Kk Kek Kek C1 LD 4 FREG a ma rau Er Al m Gog maa a DCHOTOR STATUS HIDE TACHSET B ORDER REDRAW PEN CHA 13 17 2900B TRAINING MANUAL 13 18 4 Push the right arrow hardkey to move the cursor along the RPM axis The amplitudes of the frequencies at a particular RPM are shown at the right 16 Se 14 55 11 SLOPE alevel TAGBARS s SFHH UIDEGO pH LS note WIDTH qu SOURCE 15 TACH IHPLIT oS 117 7206 A do e Reate ad A de EXPOMENTIAL 1 64 bTHCH R a aiga Tneut 1 LINEAR 1Hz 1 HkHz Fe AES w STOP 15 OCT 94 22 21 38 4nm TR gt MELLE AA T 31 PENH LEVEL C FREQUENCY 9 K ni 46 6 1 1
255. number of FFT lines to established frequency resolu tion of your measurements e Establish the frequency baseband e Select the windowing method Impact test force window on channel one exponential window on channel two 11 15 2900B TRAINING MANUAL Shaker test with a continuous signal random noise use a hanning window e Choose averaging method or detector Impact test select count averaging and the number of averages desired Shaker test select the averaging algorithm linear aver age and averaging time e Choose measurement units e Setup triggering if using the impact method e Set the input range gain for the A D e Attach the transducers to test item Setting up the Model 2900B for Modal Testing Modal Analysis measurements can be made using a variety of techniques The most common utilizes a two channel analyzer capable of making cross channel measurements a calibrated impact hammer and an accelerometer Integral to the impact hammer is a load cell The load cell measures the force of the hammer blow used to excite the test structure The accelerometer is used to measure the resulting response acceleration of the structure These two signals are measured simultaneously and a transfer function is calculated between channel one and channel two Following are the steps used to configure the Model 2900B for measuring transfer functions Setting up the Model 2900B 11 16 First ve
256. o 1962 5 Hz All of our 800 lines of frequency resolution will be applied to this 625 Hz span Press R S to begin another measurement After 20 seconds the measurement will be complete E Ten Eg zi z6 1 2 4 a 16 Az ed l i E 20 0900 18 EP IM PE AA A EA LINEAR S INGLE 24 ARR i Ineut 1 LIHEHE _ 1Hz 1 kHz i STOP mi JAN 98 09 225 50 56 A NN el RT me DR FREQ 1650 ARARAHz HSHH Channel 1 of 1 HORMAL d 45 2 B 15 1 5 we BBB o 2 FEM TACH 9 9 SPEED B d 133v OMS 2 IEE dotted crar INITIAL 256 EASE Hz new frequency range 2900B TRAINING MANUAL In this measurement it should be clear that we have achieved much greater detail of the of the data within this reduced frequency range Integration and Double Integration A common goal in the measurement of vibration is to extrapo late velocity or displacement values from accelerometer data This can be done in the RTA by using the integration and double integration functions Let s first change our zoom factor back to 1 so that we can view the entire 0 Hz to 2 5 kHz baseband 1 Press 1 A from within the FFTZOOM window 32 Bd ZD Gobo E TACH 8 8 SPEED B a dotted crar EASE Hz 2 Press SYSTEM to exit back to the main system menu SCREEN Choose UNITS F to enter into the units menu B3 n Bm 25 51 Chanls SLM A STHHDRD CROSS rae inre FILTER CLASS E B Bia A LINEAR SINGLE 24 ABBA Ineut 1 LINEAR 1Hz 18kH z RESET 63 JAN 958 095 Zd 32
257. o Er JOB TEST REM PART FRONT A e A TES AREASPOIHTA H Hz z A Kk Hz dotted crar HITEST PrrtrsP meters SETUP FILES AUTOSTR 7 As you did earlier type in the new area name using the alpha soft keys 13 oar BEI 37 5 ss A E c D PA A ee a m a E Dual LINEAR zBHz 1BkHz STOP 13 JA 2 u lr 14 Cae ae ee eee AE RA ee ae er Oe ee ee a Lar ss IN FILTER 24 z254 Hz Leo rF JALITY 1 d Eran d 3 de 274 O AR CN on Hil Bgm JOB TEST REM PART FRONT 50 l gcc gt AREASPOIHTA El A dotted crar HITEST If H U F 8 Then press EXIT to enter this area name If the surface area of the measurement is different change the value in square meters Then press EXIT to enter the new value 9 You are now ready to take the next measurement Press R S to begin the measurement When the measurement is com plete and you are satisfied with the Quality press STORE to store the data to memory Continue the sound power survey until you have acquired all of the area measurements for the current part and have stored them away You are now ready to go to the next part in the acoustic intensity job 10 Press part J to create the next part name 13 deu pa 45 38 POWER INTHSTY QUALITY SPL F WELOC DISPLAY note DETECTR EB HHHH LE B HHHH LIMEAR 28Hz 18k Hz JAM 9S 99 dd5 5 E 56 Hz LS TEHSITV 1 d 13 6mm 8 wat ad i PO dE 4961 BEBE E i JOB gt TEST FEH i FHET FELDHT at A A iocis gee ie veer ORO ai
258. o the display below The impulse CH1 from the hammer should be fully captured fr dod ZI US Z A SPECT C SPECT A FER CUHMER TIME DISPLAY note DETECTA REAL LEF DE II COUNT MANUAL ACCEPT Dual LINEAR lHz l1 kHz ua STOP BY JAN 98 2216415 A ern nn rn enn en enn 00 TIME ma 15862m5 ESHH lleiahted Tim d 2 408 KAT REAL 50 sR RR RN RR KR E EE RR RN NN NR R R Base Frees uenc y A EE 1657 td zB Che Ba REM TACH H a SPEED B a G ABBE ZOOM 1 152 543 2 A tp level IMITIAL HLTERH BWHORM Pe ok T TEIG SETLIP FILES AUT STR 11 26 NOTE 2900B TRAINING MANUAL 42 Press X FER C to display the transfer function This is the averaged transfer function sometimes called a frequency response function from the test item Notice the peaks reso nances of the structure A vertical offset may need to be used to view the transfer func tion To do this press SHIFT then the V OFFSET D key Press the dit arrow key to bring the spectrum into view BG LBF RD CL IE LUELLLLL LLL COUNT MANUAL ACCEPT Dual LIHEHR 1Hz 14kHz STOP BY JAN 98 22164135 in ee EE H E FREQ B3 1298Hz ESHH Transfer Function Hi D 2 d d uz MAGH1ITUDE AA AR a a a o y Baze Frees uyenc y A AHHH TriBzt Ld zH Ch2 Be TACH H B SPEED B B Ba DUNS 5 HE A bU ofset 5H IHITIH HLTEFEH EWHORM PARE T TRIG SETUP FILES AUTOSTR 43 Press ALTERN I to view the phase of the transfer function Br JAH 22 15 42 A SPECT
259. ob pee ea ee eee hate FILTER 24 250 Hz Lez dd 1 2 2 HOF YAL EB oae RR dl M pa rax end dar iE cere d patiar des ed DIFF Ph 62 8 zns 7 88 xd TACH Ha SPEED B d doatted crar s Z z 8 z IMITIAL 1 0 SIG GEH INPUT clock COLOR MLS FILES RESETS Then choose 1 83oct B to activate the 1 3 octave band digital filters Press short G to select the short filter y 19 57 29 T aE lona short reverse I SPL B ABBA 140 NN ni o WE OR N N K ue eee ge ce LR HA AA c Rae far EXF HEHT T DL 1 78 i Dual LIHEHE ZzkHz z kHz i RESET 12 JAH 93 19 55 53 ai I ETE Em p RARIUS Desa E en egt FILTER 24 z756 Hz Leo i Channel 1 of 2 HORMAL i d 35 3 A a By ie eel det aie aes alg a Ue tae VE E UR EEE Ae rues sott actos Sie ee a A DIFF Fhz Be Sn T He imm i TACH H H SPEED B d datted crar Z s Z IHITIRL 199 l 1 ne z amp BBline 48aHline SbBline FFTZOOM WINDOW EASE Ed Press EXIT to get back to the System menu Next we need to select the high and low pass analog filters For this example we will set the high pass filter at 20 Hz and the low pass filter at 10 KHz To do this press INPUT K te red 19 5v 82 Chanls SLM H STANDRD CROSS IMTENSY UNITS FILTER CLASS SPL EB BEBA aG he rad ra itera e ESPOHNENTIAL 148 i Dual LIHEHE ZzbHz zikHz i RESET 12 JAN 93 19 55 53 aei da e FILTER 24 254 Hz L 3 a id 1 ys NORDAL BB TT TTT DIFF Ph 62 8 zns 7 88 Belle TACH 4 46 SPEED B d z doatted crar COLOR MLS FILES
260. ocity spectrum Press integrl D to activate the single integration feature E E citat 14 te weit Mim 0 de See age R l ek ign tae ice tah T K Gat R Satine Sato us E Sa NN Ge Pitta ta otek C ae R tae a LIHEHFE SIHSLE zH EE Ineut 1 LIHEHE 1Hz 1BkHz FESET 83 JAH 92 995 Zd5 32 34 i R TEN AAAS Ges i TA A Cex N E de CU TRE TES NEN der A A aer E E E der R E des O ub Efe FREQ QG z HRORRHS HSHH Channel 1 of 1 HORMAL z 115 H e 87 7 lep fai Shs R A N EO a O Gas iwi Sime in 01 SE TACH HL SPEED B El QG EH solid crar INITIAL NOTE This selection will be reflected in the upper right side of the LCD 4 T D 5 6 L 7 18 az do Bese sl SLOPE name SAME ER LUHITS Hoise F mU cal U cal level E EE 5 A RE H R NR a a a OE PUE Sat N E R IE LIH C L ARR L npu L HE 1Hz 16kHz FESET 63 JAH 2 995 2295 q 1 4H E FREQ Ae HARAHZ HSHH Channel 1 of 1 HORMAL s 152 9 E 125 1 TACH 8 8 SPEED B a 2 E solid crear IHITIHL dB vU SPL G under under under under Under We now need to modify the calibration value and label to read in velocity units We are currently calibrated to display the data in g s Since the integral of a g is meaningless let s create a velocity unit labeled ft s Press name B to enable the label unit feature B3 ek BEE Soi 31 SAME k UNITS Hoise F ml cal U cal level G H E ciat amp Bi s Wc eh BEL E 2a RR MPa RC iN nitur gr A RA VAN caca AR NES 0U a S AC LINEAR INGLE
261. om 23 568 195 235 229 OH OFF OH RUM OFF RU amp HTT 2HTT SFL zB 2090 2H A ae eine A CURATE A Gore vacuae ta Se Herne de a a vay cet P ce fale iby cie i cay ata at NEP gee LINEAR SIMGLE zA 7 ARB Dual LINEAR zBHz z kHz STOP 23 FEB 98 14122138 5h MA FILTER 14 275 B Hz Les Channel 1 af 2 HORMAL 5 2 A 467 48 KA E eo gae cR ee Sed ee R ee R se eee cane DEDOS es Sel a eee A DIFF Fhz odo 5n 22 3n REM E TACH 4 48 SPEED B d R Hz Eod Hz D dotted crar ROOMS SIHE FIHEK WHITE PULS DELAY 6 Press STORE to save this first receiving room measurement STORE Perform two additional measurements at different micro phone locations and store them to the memory of the RTA 7 Turn the Pink Noise Generator off by pressing OFF B Now it is time measure the background noise of the receive room Press R S to begin the background noise measurement Store the measurement when complete memory 7 Sm 18 33 53 DH OFF OH RUM DEE ELA ATT ATT l STOP 66 F aa AA a n a A AI A E Ac ce ee DR FILTER 414 25 5 I fa Channel 1 of 2 HORMAL d dd H 36 4 Me MP A DIFF Phe 55 3 gt ne 7 31 TACH 9 9 SPEED B EB doatted crear ELAY REM SIME bd LE 63H Hz HA E ROOMS FINE WHITE PULSE 9 28 CLEAR RECALL 2900B TRAINING MANUAL 8 If you wanted to keep the memory records straight you could go to the FILES menu in the SYSTEM menu and attach notes to the records The first three could be l
262. or 3200 can save time but is not necessary 9 1 2900B TRAINING MANUAL Sound Decay Measurements RT60 s Sound decay measurements are used to determine the sound absorbtion characteristics of a room This is also known as the reverberation time or the decay time RT60 defined an RT60 is the amount of time required for a room to absorb 60 decibels of sound pressure Example Some one excites a room with a gun blast or a balloon pop and the maximum sound pressure level reached is 115 dB RT60 is the amount of time it would take for the room to absorb the noise such that the sound pressure level reaches 55 dB 115 60 Typi cal values of reverberation times are 0 1 to 3 5 seconds Highly reverberant or reflective rooms such as a gymnasium or a tiled bathroom have longer sound decay times Setting up the RTA for RT60 measurements 1 From the System menu press STANDARD C and Chanls A in order to activate a single channel measure ment 19 FEB 16 68 17 Chanls SLM A STHHPERDJ CROSS INMTEMSY UHITS FILTER CLASS EB Bee at CMM 2L Rd ta a N ERF HEHT HL 178 Dual LIHEHE ZBHHz ZB kHz RESET 19 FEB 98 16 65 45 79 Kr RR TN dl N N R toes R N AR E ME RR T a e de R E RT Gee N N R R E coy R FILTER 14 75 4 Hz Leo ears 1 ES HOF DAL D DIFF Ph 52 28 Sn 2 4z REM g TACH HLH SPEED B El z5 H8 Hz Bae Hz 206 QL HZ datted crar IHITIHL 1 0 51G GEN IHPUT clock COLOR MLS FILES RESETS 2 Since RT60 measurements are ty
263. ord you may use the horizontal keys to scroll through the stored Ln trace records The stored traces will appear on the dis play Recalling a Statistics Table 1 Press the RCL TBL J to recall a statistics table to the dis play J 19 FEB 68 51 53 DN OFF S Time dBE 5PHH F STAT HIDE EHE REDRAW 128 STORE Ln Tra SPL TOC TUM 1 8 Lol LA m J Lol E r m Lm l In On OUT Pee STDEW amp 98 520 XUHDER az Ln cursor H CHHHHEL 2900B TRAINING MANUAL 2 Enter the record number via key numeric keypad to be recalled Press the EXIT hardkey 19 FEB 62 34 41 Gh 336845 25 doe Reet dea ear ad eee nae srl ee A fc qn de EXPOHEHTIAL Inrut 1 LINEAR ZzB8Hz ZBkHz STHT OF 19 FEB Y nl e ci See is eps PE n Ln 24 z n m m l Mr w A un Dem mum AJL ELE Zr m D m en OUT IICA Pa n STOEN a del sx REN 6 96 520 XUHDEF az o ES Hz 636 Hz z Qk HZ E A Ln cursor 3 Press the Yes A to recall the table or No C to return to the Statistics menu 19 FEB 9295 35 3 126 ow RA ARE YODO SURE VAG 2 2 S68 Yee TEE EXPOHEHTIAL 148 Res Ineut 1 LINEAR ZBHz ZHBkH STOP 1 G STAT 9 FEB 95 Baio 3 ai A A E A ae cm n n zd z756 Hz 1 F i He K Lmax 4 4 T z 16 r amp r Lmin 358 9 EOZ eU O LE 39 rins LEG 72 5 gt 4 58 620 MEAN 65 3 REM x 5 78 620 STDEU 5 6 ago ae z O ETC 6 36 520 UNDER as a 24 8 Hz 636 Hz ZA BkHz Z A Ln cursar POPCO Merging Statistics Table
264. os mom m os m on on EXPOHE TIAL Input 1 LINEAR 26Hz 26kHz STAT RECALL 19 FEB 43 4 S O ee RR ee eee eee ee FEN n Ln 24 z 1 221 H rd Lmax B C co MURS UN UN 218 rirLmin 3 iod 0m mte i3 PO aCe Se aa n foc 64 36r SUNDER 68 8 25 8 Hz 638 Hz 26 8kHz Z A Ln cursor POPCO STO TBL RCL TBL MEG TEL H CHHHHEL 10 7 2900B TRAINING MANUAL 10 8 Modal Analysis impact hammer load cell p EM to channel 1 to channel 2 accelerometer SMS beam FFT analyzer What is Modal Analysis The process of characterizing the dynamic properties of an elas tic structure in terms of its modes of vibration frequency damp ing amp mode shapes emus Fal REEF Hoa Herken 3 AT giten I Berne Freer TAH H M SPEEL ecap 2900B TRAINING MANUAL Dynamic Analysis e Analytical Modal Analysis Mathematical determination of dynamic properties of a structure using the Finite Element method e Experimental Modal Analysis Experimental determination of the dynamic properties Modal Models The frequency damping and mode shape are the properties of a mode of vibration and the basis of the modal model NNNNNNNNNNNNNNNNNN m x clfx4 163 f t Modes Haw ir k 21w py E k 2 0w pi k 1 What is a mode Vibration is caused when energy becomes trapped within the boundaries of the structure moves freely within the boundaries and cannot readily escape e The mode shapes are
265. otted crar zHk 29 20 1 16k 2H 16k SAME e amp FEHHGE E T Press EXIT to return to the SYSTEM menu Next we need to establish a detector type and averaging EXIT time to simulate the slow or fast detector response time of a sound level meter Press EXIT again to enter the STANDARD feature menu 9 Within this menu Press DETECTR H to enter the detector setup menu p 115 N e R RT E NR RE UE ancl CET ae RR EEE RRR R que A E EXPOHE T AL 1 HEUL 1 A WEIG i ESET 24 FEB 95 14 64 46 age 9 E FILTER 2 Seq Hz S Z Channel 1 of 1 HORMAL d 3H A 77 TE 4 cc Gc iacebat EA ESE eae DIFF Fhz2 haT 5n PEM l TACH 9 09 SPEED B cl z E El DE trt GEH IHFPLT clock H Hz Sis z au ROOMS I 70 SIG COLOR MLS FILES RESETS 10 Press EXP C to enable the exponential detector 24 FPE 14 05 05 LIHN S LIH F EXP BT ESP ET LIH ALI TIME e SPL B BEBE 116 EO eg 1 48 WEIGHT RESET 24 FEB 93 14 64 46 ri BDG Hz S73 Channel 1 of 1 HORMAL d i H 77 DIFF Fh 27WaT Sns TACH 4 46 SPEED a d dotted crar REM ROOMS 4 ER O I X EXIT 2900B TRAINING MANUAL 11 Next we need to establish the exponential detector averag ing time or rate Press AV TIME H to enter the detector aver aging time menu ae cg 14 65 05 LIHN S LIH E EXP BT EXF BT LIH Bu TIM SPL EB ma EXPONENTIAL 1 3 Inrut 1 A WEIGHT RESET 24 FEB 93 14 64 46 FILTER 27 BDG Hz 5 3 Lhannel 1 oa
266. otted crear INITIAL DEFAULTCHUTSE gt undef undef under undef undef undef Press the STORE E key to store the present setup to one of the named softkeys a eer 15 44 46 name E SETLUF STORE gt BOOT note i SPL Pu 5564 TH A A A NN EXPONENTIAL Dual LIHEHE 202 z kHz i STOP DCT 94 54 E MS hs a a She Se Ce ee ae ee ae ce ee ile FILTER 1 ME Hz Le Channel 1 of 2 NORMAL i g B 66 2 GA L A A 2 PHONS BZ 3 Cor ob TACH H a SPEED B amp dotted crear E E Z under undet undef Under Under E a zh IHITIHL DEFRULT NOISE undef The message Push setup to store will appear on the upper right of the display B3 OCT 15 46 13 Ee A ee ion ite eor eb a pesca Push setur to store SPL 14 5568 TH urhe RR WSS e R Ow war Cheeta den da San de ae a ee A ae eine EA OC TC wee Ab ict 28 34 MD E EXF HEHT T DL 1 E Dual LIHEHE 28Hz 28k Hz STOP a OCT 94 15 38 42 SH CECI A A fat al BEE GIR late ekte ane wate oe ce FILTER H 1 MI Hz Leo Channel 1 of 2 HORMAL d B 66 2 Ab Ll A A PHO MS EZ 3 PEEL TACH 4 46 SPEED a d i z z datted crar IHITIHL under undef under Under under Under Press the labeled softkey NOISE J to assign the current setup The current setup has now been assigned to the softkey and will remain assigned to this key until you modify it or you perform a reset setup explained later You may assign up to seven different setups and may reconfigure the analyzer
267. peak fast slow impulse response typically overall SPL some provide octave 1 1 1 3 SPL s Limitations SPL is a scalar quantity provides no information on direction of sound SPL dependent on measurement environment Basic Acoustics 4 8 2900B TRAINING MANUAL D WEIGHTING NETWORKS Raoo729555555505050000o055595575 44 tQ weno ORxRRSLL555550555905555Lj 4 E Zhero rA c wn EI e O 1 D T n Basic Acoustics FAST RMS DETECTOR Basic Acoustics 4 9 2900B TRAINING MANUAL 4 10 DETECTOR RESPONSE CONT Fast detector used when measuring noise sound that is fluctuating rapidly has a time constant of 125 ms display updates quickly Slow detector used when measuring steady state sound or when one wishes to average out fluctuations has a time constant of 1 second Impulse detector used when measuring impulsive phenomena such as gun fire rise time can vary typically lt 1ms decay time 2 9 dB per second Basic Acoustics BASIC SLM MEASUREMENTS RMS amp PEAK LEVELS The peak detector shows the highest peak value for the measurement The rms root mean square amplitude of a wave is the square root of the mean squared displacementsduring the measurement For a sine wave the rms amplitude is 707 times the peak amplitude dB Basic Acoustics 2900B TRAINING MANUAL L BASIC SLM MEASUREMENTS LMIN amp LMAX LM
268. phone to channel one of your 2800B 2900B 1 From the SYSTEM menu press STANDARD C and then Chanls A to select single channel analysis a 5 18 26 17 Chanls SLM A STARDED J CROSS INTENSY UNITS FILTER CLASS PL EB BEBA SGT carried yA EXPOHEHTIBL 8 Ineut 1 LIHEHE ZBHz 2b6kHz RESET 19 FEB 93 18 18 38 BA L FILTER i4 25 8 Hz Lez conan 1 B MORTAL GA L DIFF Ph 65 7 Sm 5 94 REN TACH 6 6 SPEED Bg d S H H 6360 Hz 206 QL HZ dotted_ crar FORFCO 1 0 516 BEN INPUT clock COLOR MLS FILES RESETS If the filters in your analyzer are not set for 1 3 octave band analysis press FILTER G to enter the filter menu area a 5 18 26 17 Chanls SLM A STANDERD CROSS INTENSY UNITS FILTER J CLASS PL B BRR 140 A K RRR RRR K RR N EXPOHENTIAL 18 Ingut 1 LINEAR 2bHz 24kHz RESET 19 FEB 38 18 13 38 asi Da c REM C LM A EP LL FILTER 14 75 4 Hz LS Channel 1 of 1 HORMAL d 34 2 H 46 1 BH I cc E c c lx d BIFF Fh 65 7 n 5 ad REN ie TACH H B SPEED B B 25 8 H Bae Hz 206 QL HZ datted crar POPCEO I 70 51G GEN IWPUT clock COLOR MLS FILES RESETS Press 1 30ct B to enable to 1 3 octave band digital filters 1 1565 18 27 92 lz laoct lona short reverse SPL B BRE 190 KR RR IRN NN RR N R R KN RRR N NN 001 221111177 170771110 N N N EXPOHENTIAL 1 48 Input 1 LINEAR 2B6Hz 24kHz RESET 19 FEB 98 10 18 38 24 A AR OS PR LI P CE E FILTER 14 25 8 Hz Les Channel 1 of 1 NORMAL d 34 2 A 46 1 AH E C a none
269. pically done in 1 3 octave W bands press FILTER G to enter the filter menu G 19 FEB 16 88 17 Chanls SLM A STHHDED CROSS INTENSY UNITS FILTER CLASS Mu S A NEU FILTER SPL EB BEBA 3H DA a CES OR RE JR MODUS See by a A KE R E A a IN II o A DIA de a la EXPOHENTIAL 18 Dual LIHMEBR 2BHz 26kHz RESET 19 FEB 98 16 85 48 FA K NN Be R RN eH ae ee ee R R E RR R RR Se ae a ec ee a R R 9 FILTER 14 25 8 Hz Les Channel 1 of 2 HORMAL 373 4 A 34 49 54 9 de dN K d N PE E Wa Ae Mage clei Sm cate i T R R R ee cae O E NE one ee wae nee oe Say E DIFF h ba Ens 7 45 BEN TACH 9 9 SPEED B B 25 6 Hz Bae Hz 206 HE HZ datted crar IHITIHL 1 0 51G GEN INPUT clock COLOR MLS FILES RESETS 2900B TRAINING MANUAL 3 EXIT 4 Choose 1 3oct B to activate the 1 3 octave band digital fil ters of the RTA Choose short g or for the short response time choose reverse H rs 12 11 89 lrioct lona short reverse SPL B piana 140 Ju D c c c c x c I P HEL EXPOHENTIAL 18 Dual LIHEHR 26Hz 14kHz RESET 26 FEB 98 12 88 43 asi XX REEL QE RIEN ILI Il LLL Ai FILTER 14 z Q Hz SS Channel 1 of 2 HORMAL d 34 4 E 2 BH M LLL LL E MIL CE eM EL BIFF Fh 65 9 n 6 85 REM a TACH H B SPEED HL 5 8 Hz eae Hz zZB BEHz dotted crar IHITIHL 1991 1ne zBBline 466 line 2001 1ne FFTZOOM WINDOW BRHSE Bd Press EXIT to return to the System menu Creating a Measurement File Now create a measurement file for the measurement
270. poh Hz Ts dotted crar IHITIHL 1 0 SIG GEH INFUT COLOR MLS FILES RESETS The following prompt will appear on the upper right of the dis play DD MM YY HH MM SS prompting you to enter the current time and date via the numeric keypad 20 FEB 18 48 37 128 E p mM vy HH MM SS B BEBE 146 r rd ar ri war A A A Sue at cee caf A A O OSA ELIT E We EXPOHENTIAL 1 Dual LINEAR 2AHz 18kHz RESET 26 FEB 98 18 47 45 ai r E RR KR GA RR RR a A RA A A A Se A RRA R N FILTER 14 75 4 Hz L ya hannel 1 QE FORNAL GA L DIFF Ph 65 9 Sn 6 85 REN gt l TACH HG SPEED ALG 25 6 Hz Boa Hz 26 BLC HZ dotted crar IMITIAL 2 Press the EXIT hardkey after entering the time and date to EXIT return to the SYSTEM Menu The new time and date will appear on the upper left side of the display 19 FEB 16 65 17 Chanls SLM A STHHDED CROSS INTEMSY UNITS FILTER CLASS SPL A Em aj r A AA AR AO EXPOHENTIAL 1 8 Dual LINEAR ZzBHz zBkHz RESET 19 FEB 98 16 03 48 TH r DAA RA Te cct A A E RC A A A A A AA NA Ss FILTER 14 75 8 Hz Leo EL d 1 ES ads r A DIFF Ph 52 8 Sn 2 4z REM a TACH 9 09 SPEED B El 5 8 Hz 630 Hz 29 BLC HZ dotted crar IHITIHL I 0 5I6 GEN INPUT clock COLOR MLS FILES RESETS Activating the External Color Monitor LD Model 2500 Color Video Adaptor required The Model 2500 Color Video Adaptor permits the analyzer to communicate with an external color monitor EGA VGA or Super VGA via the printer port of the
271. programmed such that a press of each of these keys simulates a press of the softkeys or hardkeys on the analyzer To program either of these keys perform the following 1 Press KEY A D or KEY B E key D 15 or lr 14 92 32B6FC DC out IO Port KEY A KEY B Beerer RES1 IHT SPL 6 0060 TE NR RR oie Ge Qh ee A EXPOHEHTIAL 148 Input 1 LINEAR 26Hz 26kHz RESET 19 FEB 98 17 88 38 U B AN NA AAN ANO AN FREQ Aa BARAHZ HSHH Channel 1 of 1 NORMAL g 23 3 E 6 6 E AB A AA pias 6 Ta Bae RRR A E IT R OA a REM t TACH H 6 SPEED B B aa BOB 00m _ 1 10000 0060 zB dotted crsr INITIAL T LINE ing eg 1292 2406 4588 7688 19200 2 12 2900B TRAINING MANUAL The message PRESS THEN THE KEY will appear on the upper right side of the display 19 FEE 17 19 48 S266RC DC out IO Port KEY A KEY ET Se nono hom oa non ns m n n on a 3 3 o3 3 o3 n n ns m n s n nos non n gs nom s m n E PRESS 1 THEM THE EEY SPL EB ca ro E EMT GR A AR RR N in SEES RRR N N NR BR A EXPOHENTIAL E Ineut 1 LIHEHE ZEBHz z kHz FESET 19 FEB 33 11 65 36 B rcp LP LU ME h R EM IL IUE ME CN Et FEE He HRRRHS HSHH Channel 1 of 1 HORMAL g 33 9 E 6 6 MERERI TRCH 0 0 SPEED 0 9 INITIAL STALIN Seg eon E 19206 2 Press the minus hardkey 3 Press the softkey or hardkey to be assigned to Key A or Key RESET amp B Typically the R S hardkey is assigned to Key A and the R S STORE STORE hardkey is
272. r ase dd agi dii RE edi A aa a clk pete ica won ndo Mek aa da rio O wees lay edP Te a a tas che da ia ia E e DIFF Fh 65 9 n 6 85 REM 2 l TACH HLH SPEED B El 25 H Hz Bae Hz 7H HE HZ datted crar IHITIHL aS TART alEHD SHEEP LIH z Lone Auto L FILTER EXIT EXIT E 2900B TRAINING MANUAL B Press the EXIT hardkey C Press Fend B key You will be prompted to set the upper end frequency limit via the numeric keypad where the sweep will end zB FEB 25 Dl 592 Fztart Feng k Se E es Lee Les amp HTT HTT EBB 99 01 00 Fstart FETO Rese Res Lee SPL 4 BEBA 190 r h R 7 T HR aE T RR A an E T os E EE EXPOHENTIAL 1 48 Dual LIHMEBHR 2BHz 26k Hz RESET 24 FEB 93 09 265 D ea r Bagh se ae N We PTT AAA a hn hake Se edn ath 48 FILTER 14 275 A Hz Les Channel 1 of 2 HORMAL 34 4 A 46 35 GD wo Ry RRR OE QE R R R RR UK R A R ee ee ep a R R TRER ND ARR a a a N P KTR R A R 79 DIFF Pbs 65 9 Ens 6 85 ES TACH 9 9 SPEED B d S H Hz Bae Hz 7H HE HZ dotted crar IHITIHL als TART alEHD SHEEP LIH z tone Huto L FILTER D Press the EXIT hardkey The rate of the sweep can be either logarithmic or lin ear in the frequency domain Whenever one of the parameters of the sine generator is changed E Press the softkey L to select between Log and Lin 0 EEB 03 01 08 Fstart Fend R se k es Lse Les ATT gt ATT SPL 6 0060 190 Ea E x EE c OE EXPOHENTIAL 1 48 Dual LIHEBHR 2BHz zBkHz RESET 26 FEB 8
273. ra is somewhat flat across the frequency band rolling off at the higher frequencies Press CH2 to view the channel 2 autospectra ar aN 22 03 54 A SPECT C SPECT amp s FEF COHER TIME DISPLAY note DETECTE A E AO G B4 106 E Mc Pa mme NE aa tat for cles Ae COUNT MARLIAL ACCEPT IHEHEF 1Hz 16kHz STOP ar SUN a8 22 04 35 z Lo A Bos Freauenca AHAA 16 t td B FEM TACH B d B d pi ri DUZ E orok Lria level IHITIHL HLTEEH ElJHCOEEP Fa tk T TEIG SETUF FILES AUTOSTA 40 Now press TIME E to view the response time history for U channel two The signal should decay to zero as does the E measurement in the display below ul deu 22 85 25 ALSPECT C SFECT x FEE COHER XTIME DISPLAY nate DETECTE REAL G Bd 2 oe Es rou fats wis dac dE gin dera gods yak cal thn Ceci RE ad vd Na saucy sibs daly Wah VENUES RS al Har duo dae can ths faces HERES HUE d COUNT MANUAL ACCEPT Dual LIHERE i1Hz 18kHz STOP Ar JAH FS 22 84 38 HE oes T IPME Bid 1562m2 ESAA rhleishted Time D 2 d 3 456 E 4Z FEAL 2 oe S Sie Cu Ae ila f E e die lt b ie AS VINE MEUS A E ETRY ey be kes Side WEAN a ad cue ER asi ade Sun wile Aube 63 aa Sy el nay OTE de Base Frees uenc y Ae EE 16 t td z Eh2 HE ae TACH HLH SPEED a El BB ABBA FOOM 1 159 5437 E H Lp level INITIAL HLTEEH BuwHORM Pairk T TRIG SETUF FILES PRUTRSTR 41 Press CH1 to view the input time history for channel one It should also look similar t
274. ral KN ew E iid ut E RN N We rper erage p veu ce uvm pow TR N NN NTR N FILTER 14 25 D Hz Les Channel 1 of 1 HORMAL i E B 99 6 RS A E EA RR A A ERT tae Sata oe Tae T Aas satiate BIFF Fh 112 1 5n 142 78 REM Ee M M UNS ME AAN TRCH g g SPEED g g NS Bob Hz dotted crar INITIAL SIHE FINK WHITE DELAY Press the EXIT hardkey to return to the SYSTEM menu 2 25 2900B TRAINING MANUAL E E E i 2 26 Press the INPUT K key to enter the Input menu 19 ER 16 88 17 Chanls SLM A STANDRD CROSS INTEMSY UNITS FILTER CLASS SPL 0 9090 I6 r E ad Dec R RT R a OO CE A E a HT ae E E Se Aan EON EXPOHENTIAL 1 E Dual LINEAR 2B8Hz 2BkHz RESET 19 FEE 98 16 85 48 rar ao a tn a a Gace NE O e a e a O A a FILTER 14 zh Q Hz Leo Channel 1 af 2 NORMAL d 23 8 A a aB r AAA EM BIFF Fhz S78 Sn 7 45 REM TACH 8 8 SPEED 4 8 3r E eee ee ee ee ee ee 25 6 Hz Boe Hz ZH BLC HZ dotted crar INITIAL I 20 51G GEH clock COLOR MLS FILES RESETS Press the A WGT I key This is what effect the A Weighting filter has on a spectrum 20 FEE 18 25 28 a U 28 U 200 U AUTO RA TEST SPL 18 7888 EXPOHEHT IRL 17 Input 1 A WEIGHT STOP 28 FEB 98 10 24 45 FILTER 14 25 0 Hz Le Channel 1 of 1 HORMAL d 39 8 r 96 2 DIFF Ph W6T7 Sn REM TACH 8 8 SPEED 4 8 H Hz A dotted crar INITIAL 1 20k 2020k 1 18k 28 10k SAME RANGE Press the C WGT J key This is what effect the C Weighting filter has on a spectrum 20 558 18 27 16 Bu
275. rbs the reflecting sound that remains from the now inac tive speaker amplifier This will continue for 1 second until the 2 second Autostore endstore is reached At that point the RTA will cease capturing spectra The end result is that you will have 40 spectra 20 per second for the 2 second measurement that will characterize the reverbera tion time of the room 16 Press SYSTEM to go to the System menu SCREEN SYSTEM Setting the Signal Generator Delay The next thing that you need to establish is the noise generator duration As mentioned for this test you would like the pink signal generator to automatically shut off 1 second after the Autostore measurement has begun 1 Press SIG GEN J to enter the Signal Generator menu udi 16 88 17 Chanls SLM A STANDRE CROSS INTENSY UNITS FILTER CLASS SPL B BeBe A EXPOHEHTIBL 1 3 Dual LINEAR 2B8Hz zBkHz RESET 19 FEB 938 16 65 45 o FILTER 14 25 8 Hz L Z Channel 1 of Z HORMAL l d 23 8 54 r ROERE E RE TA RA O Gan E one DIFF Fh nz S n Ta 43 REM TACH 9 09 SPEED B 4 z datted crar H BkHz IMPLIT clock COLOR MLS FILES RESETS Since you want the noise generator to turn off after the mea surement has begun you will use the Off with Run feature 2 Press OFF RUN D zH 96i 13 43 25 OM ATT ATT a Ti Ti cC w Al E a Ti Ti N Al E SPL B GRRE re r X Gb E Ge amp OW XX WOR RR R K R RR A he RRR R K RR x x LIHEHF
276. records that will soon be acquired 1 Press FILES O to enter the files menu BE 16 88 17 Chanls SLM A STANDRD CROSS INTEMSY UNITS FILTER CLASS SPL EB Bee at r R de RS E R N NR R con RE AR e E salsa Aa rE R ATE R NN adu ter ee e des SA EXF HEHT T DL 1 78 Dual LIHEHE z26Hz kHz RESET 19 FEB 98 16 65 45 TH r RAO N we ede s Hl E R stand ate Ae Ris EC dee OC dc del ate eh dart A E ae cw A TED a FILTER 14 75 8 Hz Leo E du 1 ES Ea He D DIFF Ph 52 2 n2 2 4z REM gs TACH B SPEED B El 25 8 Hz 6360 Hz ZH HE Hz E GDE CESE INITIAL I O SIG GEN INPUT clock COLOR MLS FILES RESETS Press create A to create and name a measurement file zB FEB 12 14 14 Create ons T disk t format Memoria Used Z Disk Used Hemor Free robes Disk Free ENDE E 1 DATE TIME MAME DATE SK TIME SIZE MEMORY 7 delete rename men delete rename 9 3 2900B TRAINING MANUAL 3 EXIT EXIT 9 4 Using the alpha keys type in a filename such as ROOMS 26 FEB 12 15 27 A E C D E F IE H Memory Used 296 Disk Used Memory Free EMO Disk Free Enter nen name HAME DATE T HAME DATE TIME SIZE MEMORY F Press EXIT to enter this name Notice that the filename ROOMS is shown in the file display along with the date and time of the file creation 26 FEB 12 15 16 create RECORDS t disk t format Memor Used 312 Disk Used Memory Free rrarro Disk Free nory _ _ _ 1 S MAME DAT
277. rey IHITIHL lthresh hthresh A Prev H Hext FEEL SOLID DOTTED BOTH Averaging time of the Impulse detector is 35 milliseconds but it is also characterized by a very slow 3dB second decay rate POET 19 81 32 ETEB FEPLACE HUEFHGE Auto RE Auto AL note l Hote TEST 1 i B 1606 a A e Ge ae RR sae A o e ld o ie es ae E r T EXPONENTIAL 18 bT IME Ineut 1 LINEAR 24Hz 246k Hz STOP 14 OCT 94 17 24 43 TH E A AR FILTER H IMPULSE Leos Channel 1 of 1 vzTIME Ld 57 2 d 54 at aah tan tanta ase cored f A as a da dy ecu a ta a EXTAT en Mh cu H A orda AEIR a RT6A 28 165 ctr 1 4454 i THRESHOLDS 468 48 25 LOC B pd EET B 1066 18 668 thew Pres INITIAL lthresh hthresh A Pren B Hext FEEG SOLID DOTTED BOTH Leg is a parameter used for the analysis of time varying acoustic signals It represents the steady level which integrated over the measurement period would produce the same energy as the ac tual signal The time used for the calculation is the elapsed time since the last data reset E 15 86 39 HORMRL Lea MIH MAK SEL DISPLAY note DETECTR Hote TEST 1 25 3425 161 EXPOHEHTIAL 148 Infut 1 LINEAR 28H2z 2hkHz F ii OCT 94 1 FILTER 24 Zoe H Leo Channel i E 1 HORMAL 2BH2 28k Hz d LOC LEG Sel 124 6 Peak 117 5 E f dotted crar IHITIHL LEG Wei ah SETUP FILES AUTOSTR 8 3 2900B TRAINING MANUAL Changing the SLM Analog filters 8 4 EXIT In the default setup of the SEM mode of the analyzer the A w
278. rify that the impact hammer signal is connected to chan nel one of your Larson Davis Model 2900B and that the acceler ometer signal is connected to channel two 2900B TRAINING MANUAL Turn on the Model 2900B analyzer After the analyzer has completed its bootup procedure enter the System Menu by pressing SYSTEM Next press CROSS D ar TEH pBi dz 04 Chanls SLM A STANDEDA CROSS 7 INTENS Y UNITS FILTER CLASS SPL EB BEBA 9H A A E A E a A EE O 26 Goa Mencia R e ra pad 2 ane EXPOHENTIAL 16 Dual LIMEHR 2BH 26kHz RESET r JAN 9S 615 295 259 DE RON IMITATA TITVSAI PETITUM FILTER 14 25 A Hz Les r Channel 1 of 2 HORMAL d 735 8 A 34 49 54 A ARDOR Kw SELLE R R RR E ET E ud el 73 A A S RR eta A a a AO ES BIFF Pbs 52 8 Ens 2 45 REN g TACH B H SPEED B B z5 H8 Hz Bae Hz 206 DL HZ datted crar INITIAL 1 0 51G GEN INPUT clock COLOR MLS FILES RESETS CROSS enables the Model 2900B to measure cross channel properties The transfer function is a cross channel measure ment between channel one and channel two Next the analyzer needs to be set up to measure in narrow band or FFT mode Press FILTER G The analyzer is now displaying an autospectrum Sr Blidziad Chanls SLM A STANDED CROSS IMTEHMSVvY UNITS FILTER CLASS SPL B etm at r R ie E E LE A A RR R R N ER ce a A EXF HEHT T DL 178 Dual LINEAR ZBHz zakHz RESET ur JAH 95 61 39 25 TH r R A NARRAN A RA Er RES FILTER 14 75 8 Hz Leo oo a lof ao D
279. rs 1 Connect the output of the tachometer to the TACH INPUT of OFF the Model 2900 Attach the accelerometer either via a 950B or ON AD012 adaptor to the Channel 1 input Press ON to boot up the 2900 2 Press SYSTEM to get to the main System menu SCREEN SYSTEM Ea 3 Press STAND1 B to enable a single channel measurement SFL B BeBe GA sete denuo vao iei duci edel edis quic sip edid EXPOHEHTIAL 1 8 Cual LINEAR 2B8Hz ZBkHz RESET 15 OCT 94 16 13 55 AA hehehe FILTER 814 25 6 Hz L 3 Channel 1 oP 2 NORMAL r x A 34 7 ID D ES EE EE O PHOH5S 53 5 LOC AR A se ee TRCH 9 7 a SPEED 9 a H pp Hz Jd Bk HZ dotted crar INITIAL Ivo HOISE IMPUT clock COLOR SETUP FILES RESETS 4 For this exercise you will use FFT filters and analyze the W data in a range of 0 to 5 kHz frequency baseband Press FIL G TER G to enter the filter menu 15 OCT 16 49 19 SLM STAND 1 STAND 2 CROSS INTENSY UNITS FILTER CLASS 56 KKR RN R R R R R R NR RRR RR NR R R R R RN we a RR e X we a a a SPL B BEBE AH a usnm girade NS ee aai R farg ettam pe aoe E a EXPOHEHTIAL A Input 1 LIHEBR 28Hz 2B8kHz RESET 15 OCT 94 16 47 52 4n KARR Um DOCU E ES ee a Be a a ake IECUR AR 1 ELSE JE ee Gee R R R E GALE deu Je UE Rom ES TN SL IGI ADEL me Bn obe UR FILTER 14 75 8 Hz Lee Channel 1 of 1 HORMAL d x A 34 9 RR e eeaeee PHOWS 55 3 LOC ole TACH 6 6 SPEED B amp El H 55H Hz A HE Hz dotted crsr IHITIHL 1 0 HOISE IHFLIT c
280. s 10 Press endstore D Z S 13 35 43 OFF bra T IME delta enastor note SPL B HHHH TH KK LR O IE A c s R a LIHEAR FEPEAT BH ASAH bT IE Dual LINEAR 26Hz 18kHz RESET 26 FEB 98 13 31 27 54 A AO A R E O p tL I LE FILTER 14 25 8 Hz Sr Channel 1 of 2 HORMAL B 2 B 23 6 AB i e LER eL det dar cy cw UAE eR Qo EQ Uo A A Um um dis Qo ES ML set decl Ue em ED UE UE o LED oer Dec BIFF Pbs 28 1 nz dd REN ai TACH 9 9 SPEED Bo dotted crar ILES S Z z z ROOMS byTACH TACHSET F TRIG 9 9 2900B TRAINING MANUAL 9 10 EXIT EXIT 11 Type in 2 0 seconds as shown below 26 FEB 13 37 58 38 E Ta ie eae END TIME 9929929962 551515 TH i cal chant A RA MET Ges tee feat o fava le a okt ate vives Ga GD ET ters wie day Gl ST Je EN dez actos e Ser IT ee LIHEHE EEFEHT B ASAA Dual bTIME LIHEHE 26Hz 16kHz RESET 26 FEB 93 13 31 27 2 r AI NN TENIS FILTER 14 75 8 Hz Sri Channel 1 of 2 HORMAL d i B 23 4 3B QUE nr EE MISERE MY EET 22 P TIE BIFF Fhz z8 1 Sn 23 REM ai J i TACH 4 46 SPEED B d dotted crar ROOMS 12 Press EXIT to enter this endstore time The delta is the parameter that establishes how often a spec trum is to be captured you will choose a delta that matches the averaging time that you previously established when you selected the linear repeat detector Thus you will use 05 seconds 13 Press delta C zB FEB 13 35 43 OFF b 5TIME delta endztor note CID SP
281. s 1 Press the MRG TBL K to merge a stored Stats table into with the active stats table K 19 FEB 08 51 55 H FF S Time dABE SPAN E STAT HIDE CLEAR FEDFAM 125 a 4 ae ee we Hes E RR RR A ecce A ow EUM STORE e Ln Trace L 11 6668 140 Se sp A a he fe ee a A ee intel Send FB i a ee Ge arte die tania Say Sa tab thee ie RS a ae ld GES eat a Sete EXPOHE TIAL Inrut 1 LIHEHR 2BHz 2 6kHz STHT STOF 19 FEB 3 4 ai sce wd cR Eie cm s c e eei Re ar aa ck def ml S e CES Kel e RIO UN WC O wl ux FEH Ln 4 166 Fre Lmax i 54 6 8 5 ee ana 2 T K A c SS E date side dt 984 os E R TRT N E ELE A A ES 3 zu TAI LEG 2 5 mr d 4 58 20 MESH 65 4 REM 5 rB 620 STDEU 316 19 ar Set 5 98 520 KUNDER 03 6 E a at x zZ n cursor POPCO STO TEL FCL TEL MEG TE Ms CHAHHEL 2 Enter the record number via the numeric keypad to be merged 19 FEB 995 34 41 126 Al m m MV wt mung JONA lili Cnt L lad TA N Be ag aa WT mm L ace m OA OUT IICA Pa 25 0 Hz 636 Hz 2 BkHz E A TOS tus 10 6 2900B TRAINING MANUAL 3 Press the EXIT hardkey The message ARE YOU SURE will appear on the display To proceed press YES A To EXIT abort the recall and maintain the present Stats table intact press NO C Upon pressing Yes the new merged traces Q and statistic table appear on the display A mZ e c A MIDE LEA pd PL 11 6668 146 moron om on n m n n n n n n n n gel r le x Roo k koh Rh nh m om on oho hon oh on om
282. s 7 435 REM TACH 8 8 SPEED 4 4 9 HE z OFF IMITIAL Er S N WINDOW BASE Ed Background on FFT Windows Windows are used to prevent spectral leakage Without getting into a long discussion about FFT theory leakage is a phenomena that can occur as a result of the certain assumptions of the Fast Fourier Transform algorithm As you may or may not know FFT analyzers capture time blocks of data assumes they are periodic and then applies the FFT algorithm to transform the data blocks into the frequency domain 7 4 2900B TRAINING MANUAL If the time signals that are processed are not periodic as in the case of a sine wave that has not completed an integral number of cycles the energy from the non captured portion of the signal leaks into adjacent spectral line in the frequency domain The result is a distorted frequency spectrum Leakage also occurs when measuring transients that are not entirely captured in the time block and when characterizing random signals The LarsoneDavis Model 2900B offers a variety of window choices Each has its relative strengths and weaknesses In gen eral the Hanning window is preferred when one is measuring periodic cyclical signals or random signals The drawback to the Hanning window is that it can attenuate the signal ampli tude If amplitude accuracy is critical a flat top window can be used The drawback with the flattop window is that you may lose the ability to resolve small sig
283. s connects to the optional ADPO12 adaptor which is plugged into the input channel 1 Press the SIG GEN J key to enter the Signal Generator menu MB 16 09 17 SChanls SLM A STRHDRD CROSS IHTENS UNITS FILTER CLASS SFL B aaa aj X X lp cp I C M A E E EXF HEHT T DL 1 9 Dual LINEAR 28Hz ZBkHz RESET 19 FEB 938 16 65 45 79 KW RR N R RRR N N NR RW RRR XR RR RE N NN RIR RR RR N RR IR NIN NR RR KR RN R FILTER 14 75 8 Hz Les a 1 Es ae r D DIFF Ph 52 2 Sn 2 42 Sen eU RR RRR R NR de QC UE R E UM LU UE CUERO cwn A NOUS N N NN R K N TRCH 9 a SPEED 9 d 25 0 B D HZ dotted crsr INITIAL INPUT clock COLOR MLS FILES RESETS Press the Pink J key to select Pink noise Sieg oo T NN QUAE E NM uM E SFL B aaa 146 O a tun dani sin eos EXF HEHT T DL 1 78 Dual LINEAR 28Hz ZzBWkHz RESET 26 FEB 938 H3 36 51 SH M je a do Site Jae RA tmr a ada Ges ya ur a de tay a cio des CES CR 6h Neh des Sine Sat dae Dac apio uae En cap ROME FILTER 14 75 8 Hz Leo pa irda 1 a io GA L DIFF Ph 65 9 n2 6 85 REM THCH H a SPEED B d 48 s Hz O A SEL Say pl RU R CR KR SET CL RT Cab an Gus tml Ga Jarre ik we Se d uz wee Ese INITIAL SINE FINK WHITE PULSE DELAY Press the ON A key to turn on the Pink noise Push R S to view the pink noise 20 758 10 23 26 0N OFF DM RUN OFF RUN MT CRIT SPL 158 9000 3H A R EB Be aE RRR oath R ta deta EXPOHENTIAL 148 Inrut 1 LINEAR 28Hz zBkHz STOP 2A FEB 98 1 22 12
284. si M URS decns O idu iy disco art AREA POINT 25 8 Hz je 1B mHkHz Z A dotted crar HITEST job C Part area PretrsP meter SETUP FILES HUT STE 12 27 2900B TRAINING MANUAL 11 After you have created the new part name press EXIT Con tinue the test modifying the area names and sizes as you EXIT go along Hate dEFI qu ZD m SH o rr a 2 22 oe ern prm ETHER zB mdp 13 aan aLa EE 295 3 5 POWER INTHSTY QUALITY SPL F WELOC DISPLAY note DETECTR ua STOP 13 JAH 33 FILTER 24 238 Hz Les er INTENSITY 1 de 13 8mm d i SH OEC EL E NE NR X E RETE UE a T tange qupit E stor dts F lJ z Z21 ztdE 2101 cime l JOB TEST FEM FART BACK aj A T da de fata PF GET RARE Ks O Id ics reo xsara acie d AREA FOIHTI1 25 Q Hz SHE Hz 16 BkHz A dotted crsr AITEST Job Part area PretrsP meter SETUP FILES AUTOSTE 12 When you have completed the acoustic intensity test of the ob you can use the summing capabilities of the 2900B to generate sound power totals for the entire job or for individ ual parts 13 To do this first press POWER A to bring up the sound Q power summation menu 13 JAN 96 43 33 IHTHST QUALITY SPL F VELOC DISPLAY note DETECTE Hote dErhl m zB Em wirt SINGLE ZD Dual LINEAR ZBHz 1BkHz F 13 JAH 98 uu 3 FILTER 424 2oH Hz LYS IHTEHSIT 1 d 13 8mm l t 6 POW S1 ztdB 261 bcn JOB TE PART BAC IS N A Ae Sie dee oen erecta n N aa he AA E AR RO LIE REPRE AREA FO IHTI 25 8
285. sis menu zn E 2900B TRAINING MANUAL 25 Press DETECTR H to enter the Detector averaging menu 15 OCT 20 19 27 NORMAL Lea MIN MAK SEL DISPLAY note G B BEBE EXPOWEMT TAL 1 5 Ineut 1 LIHEBR 1Hz 1B8kHz RESET 15 s a4 205 071 Bd l Bo GpH H4A Channel 1 of 1 NORMAL d 95 2 a 71 8 m OE TACH BH SPEED a QG HAHA Z 00m 1 eee a dotted crar IHITIHL ROOMS uzRPM STHT Mx S5rec F TREIG SETUF FILES AUTOSTR 26 Within the Detector menu choose AV TIME H to modify the integration time 15 BET 29 10 49 LIM S LIMR EXP __ EXPOLN COUNT S COUNT R B BeBe 1 8 Ineut 1 LIHEBR 1Hz 1B8kHz RESET 15 OCT 94 28 87 54 FREQ AA Bm 4 x 8GGGHz H4AA H Channel 1 of MAL 95 B ED E R pag UES A O isi R piu GEC SEE E R T L RR AA AAN RE l I TACH H H SPEED a db dotted crsr INITIAL 27 Press 1 64 A to select the fastest exponential detector inte eration time 15 ES 28 11 11 CED s 122 s RRR E 1 16 gR Tec ae EE 1 5 E Cas ca iT Minas SEEDS l z B Hga 1 8 Ineut 1 LIHEBR 1Hz 1B8kHz RESET 15 OCT 94 28 87 54 FREQ AA Bm gt E BaanHz H4AA Channel 1 of 1 HORMAL d 95 2 71 5 ED IIT RR A MA A R R N RT RN at de ER ETRE R R RRR R a a ea A I i eee eee n au dotted crar INITIAL 4 B 16 32 6d 128 256 512 EXIT 28 Press EXIT to return to the STAND analysis menu Setting the byTACH Autostore parameters 1 As mentioned earlier you will be utilizi
286. source 6 Select Zw FREE A to display Zwicker Free field loudness function to the spectrum 16 FEB 2B 17 13 2w FREE Zu DIFF SPL 1 9258 EXPOHENTIAL 1 3 Dual LIHMEHR 2BHz 26k Hz STOP 16 FEB 98 13 88 33 FILTER 27 266 Hz L3 Channel 1 of Z Zwicker one FREE Fh 81 6 5n 17 87 TACH 8 8 SPEED B a Zuicker crs DOOFUS 7 Press the EXIT hardkey twice to return to the Main Menu 2900B TRAINING MANUAL Annotation of a Measurement O 2 CURSOR With the LD analyzer you can attach a note to each spectrum stored This feature can be found in both the RTA mode and the SLM mode of the analyzer 1 Press the DISPLAY F key from the Main menu 2 Press the note G key uie 23136141 141 1 43 SU SET USER Multi Hote SPL z2 S56 38 O ah a ab ah Ra R ae a ite N RR ite Ge ae SR Ske SP a 4 EXF HEHT T DL 1 E Dual LIHEHE ZzbHz zEkHz STOF 25 FEB 98 23122144 rar A O A OR MM RN ES FILTER 14 25 15 Hz L 3 E Channel of NORMAL 28 ee E edo Exckcw x x0 a PLN da BIFF Ph ad 7 ane 22 22 REM OE TACH 4 46 SPEED Bg d H Hz Eod Hz doatted crar DUUE UZ Dis UST U SUN BHOR Alpha characters A through P will appear across the top and bottom of the display To select the rest of the alpha charac ters press the SHIFT hardkey and Q through Z will appear A flashing cursor will also appear in the middle of the display this is where you can enter the desired note B3 OCT 15 88 43 H B C D E F B
287. spectra 18 Next choose AV TIME H to establish the number of spectral averages for the FRF measurement Br JAH 61 34 57 LIN S LIH E EXP EPU N COUNT S COUNT F COUNT BL TIME JBN Burr C LIMSS LIMER EXP EXPO N COUNT Gas SPL 100 A AO e A ae tae cam DW COUNT MANUAL ACCEPT Dual LIMEHR 1Hz 16kHz RESET ar JAN 93 61 54 20 Se A R G RR Ra D E RT E RT MEN der Pe ERAN ae Sue steely R EE MEN Genet A Aan ch FREQ He HRORRHS ESHH Auto Spectrum D z 6g II Base E re uencoz AA AABAA REM i TACH HLH SPEED a El Bi x EH dotted crar IHITIHL 19 For this test we will use 4 averages Press 4 C um BLE sais 1 z 5 16 32 6d 125 SPL LA COUNT MANUAL ACCEPT EAR _ 1Hz 1BkHz RESET Hr JAH 93 61 34 26 sa S R A A E AN A RA FRE He HRREHS ESHH a D Z eg cy Sod E A e OI de Cet KE Ja ae E Ue dec oa Ta LO d ODORE RET a E CAE oe ee e Tl Base Freasuencu BB 9069 REI ot TACH A SPEED a El 96 AGE O0mM 1 148 875 E HA dotted crar IHITIHL z256 alz 1024 2048 4096 e197 16354 32768 20 Press SYSTEM to get back into the SYSTEM menu 11 21 2900B TRAINING MANUAL 21 You now need to define the measurement units that we wish to work with Press UNITS F to enter the UNITS menu Note that Channel 2 is selected G c I prs m LH m pl m r1 a a m i LA r D LA n at mi Al pe C1 7 a LA LA m 4 m LA Ll m LA T I r m 7 r1 r D LA LA S
288. standing wave deformations of the structure at certain natural frequencies caused by trapped energy 11 2 2900B TRAINING MANUAL e pe aa aT T pas 1st Mode gt 2nd Mode gt JP c Lan Pre TER ri ig s 3 d jet er ya P pr gt a 0 Er om f e M of E Os 0 a ai e Es e E Fi A e 1 E aom 7 A O a 4 x nam y P ct e mn re E S E a ud The Frequency Response Function FRF A structure s overall vibration can be described as a summation of the vibration at each of its modes Frequency Modal Parameters from FRF s e Damping and frequency are the same at each measurement point e The mode shape is obtained at a single frequency from all of the measurement points 2900B TRAINING MANUAL Why Use Modal Analysis e Verify analytical models Verify the accuracy of FEA models by providing an inde pendent check of the modeling accuracy Experimental modal analysis can be used to provide damping values for the FEA model Ifexperimental model and mathematical models are closely matched the FEA model can be used for further analysis and simulation e Troubleshoot noise and vibration problems e To evaluate fixes 2900B TRAINING MANUAL Making Modal Measurements impact hammer load cell o Ve gt to channel 1 to channel 2 Co M C CO C C C A accelerometer SMS beam FFT analyzer Excitation Techniques e Impact Hammer e Shaker e Servo
289. sure level is averaged for 8 32 seconds Sound Power Setup using the Sound Pressure Method measurement surface v microphone positions 12 6 2900B TRAINING MANUAL Sound Power Calculation for Hemi Anechoic e Step 1 Calculate the total averaged sound pressure level L 51010g 1 10 99 95 n the number of microphone locations Lp the total averaged sound pressure level Lpi the sound pressure at each microphone e Step 2 Calculate the total sound power level Ly Ep 10 log 5 54 Lw the total sound power level S the total area of the measurement surface So the reference area 1 square meter Sound Pressure Method pros and cons e Advantages good repeatability standards are well documented instrumentation is relatively inexpensive and easy to use e Disadvantages anechoic and hemi anechoic chambers are very expensive field measurements are difficult or impossible test is very time consuming setup is very time consuming background noise air conditioning voices etc may invalidate the test 12 7 2900B TRAINING MANUAL Why Use Acoustic Intensity e Does not require a special test space e Measurements not typically affected by steady and station ary sources e Easy conversion to sound power e Yields location of sound sources e Provides a means to rank sound sources The Acoustic Intensity Probe The Acoustic Intensity probe consists of two phase matched microp
290. t 10 amp Opt 11 Option 10 Noise Generator The Option 10 Noise Generator has the capability to produce Pink noise or White noise and control the mode of operation of the noise It is accessed in the System Menu 1 Press the NOISE J key from the System menu 17 gi p3 42 48 SLM STAND 1 STAND 2 CROSS INTENSY UNITS FILTER CLASS L EB BEBA GD E a a E YEN R R RTE ral T ea E ke R aT Sat Ge ras in R eo HAUS CB nate EXPOHENTIAL 148 ual LIHEBRE 28Hz 28k Hz SET 17 OCT 94 63 36 11 4A R ae BT a E A A E eG ce aa ee ie A A A FILTER 14 75 8 Hz Les Channel 1 af 2 HORMAL 25 A 34 7 A oe Gael MD E E us A A QE UNE S T E ea en UA SO ELI QU IR UR OR FPHONS S LOC TACH 8 48 SPEED B d El A Mk Hz ranae 115 OCMOTOR IHFUT clock COLOR SETUP FILES RESETS Select the desired spectral content by pressing the PINK M or WHITE N keys o c unen UM Coss OFF OR RUN OFF RUN BURST l SFL B ABBA 115 o Vidas c TTT A O AGES oe A NS EXPOHENTIAL 18 Dual HEBR 1Hz 28kHz RESET 6 OCT 94 15 28 17 at cw EL mea A COE IONS D AAN PE IA af qud FILTER 24 z254 Hz Leo i Channel 1 of 2 HORMAL lt d A 66 7 TH de E 78 Va wet ott c T sera a er SG ieee eee PHONS 22 5 DE d ww A IN aw urba uw ur woe ts Wi NOT TE SR RW DE TRCH g H SPEED g H SD Hz she Hz A Ak ls noise HELA INITIAL DELAY LEVEL PINK M Equal energy content per percentage bandwidth WHITE N X Equal energy content per constant bandwidth 3
291. t the RT60 registered is cleared and all RT60 values for all of the frequencies are set to zero You are now ready to curve fit the data and fill the RT60 register eg OCT 16 51 18 RESET Auto RE Auto AU note RT B i SPL AVERAGED rn IN MN MM EESTI ESA Seil R soo pt dete du L IHEHE FEPEAT A HA KT IME Theut 1 LINEAR 28Hz 2 kHz RESET 88 OCT 34 15 82 54 B5B ILIUM A O Sed a af 25 4 v KAR Hz Leos i RT amp B DATA x z5 DA AO ds acia R RTE 0 De thea pP RT6B HD RRUG ga l AutoTH Max 25 8 5 0 LOC p E TRCH SPEED 3 z E ZEA both creses ROOMS lthresh hthresh Auto TH SOLID DOTTED edit 10 Press EXIT to get back to the decay curve of the 500 Hz band EXIT frequency 9 18 EXIT 2900B TRAINING MANUAL 11 Since the solid and dotted cursors have already been placed on the beginning and end of the linear part of the decay curve you are ready to fill the 1 6 kHz band of the RT60 reg ister Press REPLACE C zH as 19 34 37 RETE NEEPLACE AVERAGE Auto RE Auto Al note Hote SPL LINEAR FEPEAT Dual HE l i 2 9992 datted cran FOOHS lthresh hthresh A Prey A Hext DATA SOLID DOTTED BOTH 12 To verify that the register has been filled press RT60 B to view the RT60 register ZH E 15 34 37 REPLACE AVERAGE Auto RE Auto AL note Hote SPL WERAGED LINEAR FEPEAT Em Dual LIHEHE 26Hz 16kHz FESET 26 FEB 923 15 17 53 TH 23 1 66kHz 5 3 Channel 1 af 2 v zTIME Ef Td 155 ETEA 4 195 ct 1 1868 n ld 2 4 ga
292. te Hote SPL AVERAGED EL AUR B ASAA 9 1 8580 ee rere ee a A E 3B Elem 65 535 ct B 5564 ATH Max 1 25 H Ss REM blh Dx E E E O ES A SEP MOEA aes Ua Lea 55 2 45 6 588 5 B 0506 Bag A Z D FST crar ROOMS lthresh hthresh A Preu H Hext DATA SOLID BOTH Press the right or left arrow hardkey until the dotted cursor is somewhere along the trailing edge of the linear portion of the decay curve zi FEB 15 34 37 FTG JREPLACE AVERAGE Huto FE Auto Al note AVERAGED B 4508 E 2BHz 16kHz B 15 1 EAkHz 5 2 UsTIME 1 1568 1 1668 z5 H 5 EN K 9 55 4 Z BREE datted crsr ROUS lthresh hthresh A Prey H Hext DATA SOLID DOTTED BOTH The RIA automatically computes the RT60 for values between the two cursors performing a linear regression curve fit The RT60 value for the 1 6 Hz 1 3 octave band is 0 195 seconds This is the time that it would take the room to absorb 60 dB of noise at the 1 6 kHz band zH A 19 34 37 RT66 REPLACE AVERAGE Auto RE Auto Al note Hote SPL WERAGED LINEAR FEPEAT B 6560 Dual LIHEHE 26Hz 16kHz FESET 26 FEB 98 15 17 55 DATA 32 1 66kHz 5 3 Channel 1 of z SEDE 1568 ET6B 195 ct 1868 z 5 H px i 93 8 aa A s 2 liil datted crar ROOMS lthresh hthresh A Preu H Hext CATA SOLID DOTTED BOTH There is a storage area in the RTA for archiving RT60 data It is called the RT60 register The RT60 table is a convenient place to store RT60 values for ea
293. tep will only store enough information to recreate the Ln traces and the Ln values that were active upon storing the infor mation 10 4 2900B TRAINING MANUAL Storing the Statistics Table Prior to storing the Statistics table it is recommended that a descriptive note be attached to the table for future reference See Annotation of a Measurement in Chapter 1 1 Press the STO TBL I key to store the complete Statistics Y Table to memory Note that the storage of the Stats table requires a large amount of memory in excess of 22k bytes 19 FEB 82 51 25 H FF amp Time dB SPAH R STAT HIDE CLEAR REDRAW 125 mor m om on n m on n n n n n n n Je n n m n rrr oh oho hon on on om oa m om m n m on on STORE Ln Trace SPL 11 6888 140 A lel n m m ra RR RR RR on oho hon oh oh om os mom sm os om on on ERXF HEHT HL 17 E Input 1 LINEAR 2bHz 26kHz STAT 5 TOP 19 FEB 38 H2 39 04 oko m n or m n r AS Fe ee FEH n Ln zd z756 Hz 1 186 frs Lmax B UR EE 218 tes tmin 38 5 m E E E d A PS PP A n L ETE aj 2z ZLUHDEF AS B 2o 8 Hz El Hz zH HlkHz E A Ln cursor POPCO STO TEL FCL TEL MEG TEL H CHHHHEL This step will store the entire Ln Table which will re create the traces and the Ln table to enable you to select different Ln values 1 99 and view the associated dB values Recalling Ln traces While in the STATS mode press the RECALL hardkey The mes sage RECALL Ln Trace N will appear If there is more than one rec
294. ter the Main menu 2 Select DETECTR H to enter the detector averaging selec tion menu ZH pEr 12 30 43 HORMAL Ley HIH HAR SEL DISPLAY note DETECTA SPL EB ca rar LP EE t ERF HEHT HL 1 E Dual LIHMEHR 26Hz 16kHz RESET zH FEB 98 12 29 56 SH RR RR o RT REL DE s UE le D SEL Sic DESCR D RE RRS Si S TES eae eee ee cae a N FILTER 14 eS Q Hz Sr Channel 1 of 2 HORMAL d 25 4 3B RR RR RR RR wera ANUS LEE ELLE IR d Sd EVE BIFF Ph z ZE 1 n dd REM TACH Ha SPEED B d F z E dotted crar ROOMS ROOMS us EPR STAT Mx Spec F TRIG SETUP FILES AUTOSTR 9 7 2900B TRAINING MANUAL 3 Choose LIN R B to select linear repeat averaging SPL EB ria rar D CPI PEST she Sap TA KT R R R N RAR TR T R TR R ee A A cay EXPOHENTIAL 1 E Dual LIHMEHR 26Hz 16kHz RESET zH FEB 98 12 23 56 aB r A O cay Cat say ZR INESSE EE Goh as Ges ce RR RS E EM dE ri FILTER 14 zh Q Hz Sri Channel 1 of 2 HORMAL d B 23 4 SH 9 R CIE a ee Sime R R LET bs HET R N ORL hose H R A A a Gee GS la Gee cea DIFF Phz Za 1 n d REM I l TACH Ha SPEED B d doatted crar ROOMS 4 Press AV TIME H to establish a linear repeat averaging time H 2H od 12 35 99 LIH S LIH F ExP BT4 ERF BT LINH Bu TIM SPL B amaad TH SERRE EA E c edocet an e IR eee AER EEE LINEAR EEFEHT A 2554 Dual LINEAR _26Hz 16k Hz RESET 26 FEB 98 12 35 25 zB AIL re ILL cL cc FILTER 14 25 B Hz a4 Channel 1 of 2 HORMAL d B 23 48
295. the channel 2 microphone Press CH2 to activate the channel two display Repeat the above calibration procedure for channel two Press EXIT Programming remote control keys The next step is to program the remote control keys on the 2260 or 2250 acoustic intensity probe Notice on the probe handle that there are two keys or buttons one on the front of the handle and one on the back of the handle The key on the front is KEY A the one on the back is KEY B KEY A and KEY B can be assigned any function or keystroke of the 2900B RTA Typically one assigns KEY A the task of initiating and terminating a mea surement and KEY B the task of storing a measurement Let s go with this convention 1 Press I O I to enter the communications menu 12 JAN 28 37 82 Chanls SLM A STANDRD CROSS INTENSY UNITS FILTER CLASS l 125 E A RR a car R eo A E SEL Mace oe SPL 1 6368 140 E ot AW Se aca Ge ee XS X en OR c X0 he A N EXF HEHT T DL 1 78 Dual LIHEHE 26Hz 16kHz STOF 12 JAH 98 26 22 16 ai A ELUCET EU ENTE FILTER 24 z756 Hz Leo Channel 1 of 2 HORMAL d 114 68 i 15 A E ov ox con EE ow ox o ox ea ae ae ox ew BIFF Fhzi1BHl amp n T1 985 BE TACH H H SPEED B d R H Bok Hz A kHz datted crar IHITIHL SIG GEH INPUT clock COLOR MLS FILES RESETS 12 17 2900B TRAINING MANUAL 2 Next press the RS1 INT G key SPL 1 6368 150 EXPONENTIAL 1 3 Dual LIHEHE 26Hz 16kHz ETOP 12 JAH 98 26 22 16 gi FILTER 24 zoH Hz L
296. the display labeled DISK indicating the file has been transferred to the floppy disk AS OCT 16 11 38 create RECORDS t disk Format Memora Used 265624 Disk Used 75623568 Memory Free PE Ia Disk Free 694754 MEMORY DISK HANE DATE TIME SIZE HAMNE DATE PIME SIZE PLBHT 1070372 LOC MEMORY T delete rename men delete rename 5 Press the EXIT key to leave the FILES menu 1 25 2900B TRAINING MANUAL 1 26 Transferring disk files to analyzer memory 1 2 AS OCT 16 11 38 create RECORDS disk Hemora Used 265 2d Disk Used a Memory Free Disk Free 6 C REMO RS pIsK DATE TIME SIZE Attach the optional disk drive to the analyzer Press the FILES O key found in either the Main Menu or the System Menu Select the desired file to be transferred into the analyzer memory by using the T E or 4 MI keys Press the mem L key Bi OCT 16 12 47 create RECORDS t disk O Format Memoria Used 26368 Disk Used r amp z3 amp Memoria Free 2 2029 Disk Free 694784 MEMORY DISK CATE TIME CATE TIME AAA MEMORY 7 delete rename y delete rename The disk drive will activate and the following sequence of messages will appear on the upper right side of the display A Copying file to memory B Copy done The transferred file name will appear on the section of the display labeled MEMORY indicating that the file has been transferred to the intern
297. the response of each frequency band over time The run time of the autostore is shown on the x axis of the display art 17 20 08 RT amp B REPLACE AVERAGE Auto RE Auto HU note Hote LP L HD B 1066 P cad 7 1 5 La LIHEBHRE ZBHz zBkHz RESET 12 FEB 32 15 43 15 DHTH z Bk REM Ley 72 8 P3 gB 3 doatted crar B 18588 5 ABBA PODFLIS lthresh hthresh A Preu A Hext DATA SOLID DOTTED BOTH 7 Press the EXIT hardkey to return to the RECALL menu Waterfall display of Autostored Records CLEAR RECALL Q The waterfall display function permits the sequential display of a series of individual spectra within a byTime type autostored record 1 Press the RECALL hardkey and press the A Prev N or A Next O keys to select the desired autostored record to be displayed as a Waterfall 2 Press the W Fall A key to enter the Waterfall display menu a4 OCT 23134 154 Ws Fall E AWE E HAs vsTIME KEEF 1909 R RECALL Eu Time 3 gate SPL B 1888 IS R R E EREE R TE EEE EEE EEE EE E EXPONENTIAL 18 Dual LINEAR 2B8Hz 2BkHz STOP B4 OCT 94 23 54 33 ad I p lx cx i FILTER 14 75 48 Hz LAS Channel 1 oE z ESTA d S FH HS 3 6 TACH 6 8 SPEED 4 4 brec all data H Freu H Hext 1 81 2900B TRAINING MANUAL EXIT 3 Press the following keys if you desire to indicate the Start and End spectra to be displayed and the Delta incremental record number between displayed spectra 16108 43 6
298. thod is quicker e The scanning method is more accurate Setting up the Model 2900B for Acoustic Intensity Measurements 12 12 L Connect the Larson Davis Model 2250 or 2260 Acoustic Inten sity probe to channel one and channel two of the 2900B RTA Probe cable one near should be plugged in the channel one microphone input Probe cable two far should be plugged in the channel two microphone input Connect the remote control cable 15 pin connector to the I O port on the right side of the 2900B Next insert the appropriate spacer between the phase matched microphones 13 mm or 50 mm In general the 13 mm spacer is the appropriate choice for most measurement applications In the case where one is interested in low frequency data the 50 mm spacer should be used Acoustic Intensity measurements can be done in full octave bands 1 3 octave bands or narrowband FFT Since most inten SCREEN SYSTEM 2900B TRAINING MANUAL sity surveys are performed in 1 3rd octave bands we will setup the 2900B RTA accordingly 1 Press SYSTEM to enter the main menu of the 2900B 2 Select FILTER G to enter the filter menu SPL EB cia ih ee ee o e EXPONENTIAL 8 Lia LIMEHR 2BHz 26k Hz RESET 12 JAW 393 19 55 53 BEI od cicuta ues odes io e Cache
299. to access the surface area entry field 23 FEB 13 21 51 HC HF EL surface ol ume ETH 558 mice pM C A ae o tune re IRE 3 RAGED ai r Bs 50 R A RR OE SIHGLE zu EE al LIHEHE ZzEHz zikHz RESET 23 FEB 98 10 22 38 eh r ST eid E o RR R AE gt IRAN FILTER 14 z5 IS Hz Leo ue Channel 1 a z AOR DAL r e Pre EURAS Gas AAS S Emm hic CIFF Ph Sd E n zz 3n FEM TACH 4 46 SPEED Bg d H Hz Eod Hz datted crar ROOMS L A SOURCE RECEIVE BEHCK GD CLE PG 25 Enter the surface area of the partition room 10 square meters Then press the EXIT to enter this value 23 FEB 13 23 44 186 RES FILTER 14 d 45 2 H DIFF Fh 54 8 5n TACH BH SPEED 20 ROOMS s Z a Channel 1 of 2 oe 22 35 B a8 dotted crar 26 Next press volume E to access the room volume entry field E 13 21 51 HE HE RC surfaceCvoline 5 RT amp H d A o AA a ee erm um c ooo DIFF Phe 84 2 sre REM TACH 8 8 SPEED s T gt SOURCE ROOMS H Hz Channel 1 of 2 nmn 2935 B a dotted crar RECEIVE BEHCK GD CLR PG 9 33 2900B TRAINING MANUAL EXIT gt O Impact Sound Isolation 9 34 27 Type in the volume of the receiving room in cubic meters Press EXIT to enter the volume 23 FEB 13 29 47 100 Du E Aa 14 25 8 Hz Le Channel 1 of 2 HORMAL d 45 z A H DIFF Ph 84 9 Sns 22 35 TACH Ha SPEED a d dotted crar ROOMS 28 Now that th
300. ttaufic odes GE ceuennivatentes etuen ates edt ON 2 16 PINE A 2 20 Wae de 2 22 PULSE Elva lidia 2 23 Selecting Analog Input Filters cesses 2 23 ANA A a precoce beide uet Dreids 2 27 Activating the External Color Monitor LD Model 2500 Color Video Adaptor regu Medrese 2 28 Re eai uatacen teen cote lacen tae ceten a 2 30 Snit Me NU iii 3 1 Denim NS adelerence SpeCIFUITI S uo eeu eee ioi TU euet en db dues 3 Changing from a logarithmic scale to a linear scale 3 3 Changing the Vertical and Horizontal Zoom 3 4 Checking the analyzer Dattery eei eeu eria iii 3 4 Basic Acoustic s4 1 Using the Model 2800B 2900B as a Sound Level Meter in Standard Ama ISS ee tS TM 4 14 Setting up the 2800B 2900B esses 4 14 Sound Pressure Level measurement esses 4 18 e Lel ii 5 1 BDNE aT did 5 1 Execute Te 5 3 Stonne Macros iaie aa a 5 4 PANUNG E 6 1 Vibration Measurements sssssssssssssssssssssssssssssssssssssssvsssssss 7 1 Creating a Measurement File oooooncnnncnccnnnnnnocnnnnnnnnnnonnnoss 7 1 Secc une oa a NM M NEM EM 7 2 Chapter 8 Chapter 9 2900 TRAINING MANUAL Background on FFT Windows cccccccnnnccccccnnnnnnnnnnnonnnnnnnnnonnnaninonnss 7 4 selectmb an BET Wide 7 5 Selecting the High and Low Pass Filters 7 6 Selection ds 7 7 EE TE
301. unction press the OFF O key located in the ETRIG menu The word TRIG on the left side of the display will no longer appear Time domain triggering Time domain triggering is often used for transient capture and structural testing i e Modal analysis This topic will be covered in the Modal Testing section in Chapter 10 Storage and Recall of instrument setups The analyzer has the capability of permitting the user to define a number of setups other than the default setup that was config ured at the factory 1 Setup the analyzer as desired Then from the Main Menu or System Menu locate the SETUP N key B eer 15 37 11 WORMAL Lex MIH MAH SEL DISPLAY nate DETECTA i SPL B midi TA K Bese a hae aay et ie a ek GS Se sad LE a Gah Geo cm sae MET EXPOHWEWT IAL A Dual LIHEHR 2AHz 26k Hz i STOP 63 OCT 94 15 31 46 54 s A mmm FILTER H 1 s 24 Hz Leo Channel 1 of 2 HORMAL i d 18 4 B 66 4 za PRI A PHOWS 75 3 LOC P TACH H a SPEED B B 14 pe o a Sanaa uae at al ea Sahar a dah Gaye 1 Ic EM NM T A wok Hz oH H Hz A k HZ dotted crsr IHITIHL 005 usRPH STHT Mx S5rFec F TEIG SETUF FILES AUTOSTE 2 Press the SETUP N key The softkeys I P along the bot tom of the display are where you may define up to seven dif ferent setups These keys are originally labeled undef for undefined You may create a specific instrument setup and 2900B TRAINING MANUAL store it under one of these keys labeled wit
302. ure p pa pb 2 e Intensity Pa Pb 2fAr pa pb dt e This yields the intensity at a given location and direction for all frequencies 12 4 2900B TRAINING MANUAL Frequency Domain e The Acoustic Intensity in the frequency domain is computed using the cross spectra between the two microphone chan nels I 1 pwAr Im Gay p fluid density w angular frequency Ar microphone spacing Im Gap I maginary part of the cross spectra e This computation is the acoustic intensity at a given location in a given direction for a single frequency Measuring Sound Power Method 1 Acoustic Intensity a T Mie a Method 2 KoB re J NISX Sound Pressure 12 5 2900B TRAINING MANUAL Sound Pressure Method e Performed typically in an hemi anechoic or reverberation room e Background sound pressure level should be at least 10 dB lower than the noise generated by the test article e Test procedures are outlined in ANSI 51 34 ISO 7779 ECMA 74 etc e Measurements in free field are taken in a parallel piped rect angle or a hemispherical dome around the test item e Sound pressure is measured in 1 3 octave bands at each of the microphones e Sound pres
303. v JON 98 01 56 54 ea e AS O a de ye tessa N C e ia dear einer dr ide ME de PERS 6 FEEL AA BARRAHAZ ESHH Huto Sreectrum 2 de 8 Z 23 0 GE Sin ci Das IEEE TM an pee a Ph pee aeRO EL E SEAS ge PE Pete Re E aL SRL ta A E Base Fre aLern y A ARR REM TACH 8 8 SPEED 8 8 aa ada 00m 1 246 5750 E A dotted crsr INITIAL I J K L M H 0 P 24 Type EXIT to enter this label EAN 25 Press G K to activate the label E 20143146 SLOPE name SAME k UHITS Hoise F ml cal U cal level SPL BE 1588 RKR R RN RRR 111 1155201111127 11101011 7 119001121 COUNT MANUAL ACCEPT Dual LIHEHE 1Hz 14kHz RESET Hr JAN 38 20 43 84 K Se iy E PC TUTTI FREQ HE Eb Hz ESHH Auto Srectrum Dp z d B B a 29 H EB eene eee es Base Freauencu 66 APAA REM i TACH B B SPEED B a Bia S EH datted crar IHITIHL dE HL SPL under under under under Under 11 22 CH1 E EXIT 2900B TRAINING MANUAL 26 Press CH1 to activate channel one Press name B so that we can create the label for the input channel load cell Note that Channel 1 is selected ar TBH 24144123 SLOPE SAME k UNITS Hoise F ml cal U cal level SPL Ha a RP cec xx RO RO RO AO TT T TII COUHT MARNLIAL ACCEPT Dua LIMEHR i1Hz i amp BkHz RESET r JAN 98 28 42 58 TE KN O yas fae Lave aah ay Mav O ANN FREQ Aa ARRAS SIS Hutao Spectrum 11 3 E a o i Geb Set Ve Gee A oe eure A de eq Orge dE Je cw e LE LUE ds des dm pcc NR net ec x o
304. w LO de Baze Fre uencuz AA HHHH REI d TACH 9 9 SPEED B d QG am zUUM 1 2500 0600 E A datted crar IHITIHL dB vU SPL G under under under under Under 27 Press one of the undef undefined UNITS keys such as undef L and type in LBF pounds force Enter units name LEF E Be ar JAN 24145146 A E C D E F B H ag INCID TOROS O RR A RR RR COUHT MARLIAL ACCEPT ual EHE 1Hz 18kHz RESET ur JAN 92 2 45 58 TE KN O A R ROR at RT NNN N SR ae ES a RR we a te it eo XKR A a Gt aca eR IR Ge FEEL AA BARRAHAZ ESHH Huto Spectrum d 11 3 E x ae RN Sar ca setae RE lee eo RO ey RR sat age a ee Base Fre3suenmncuaz AB HHHH REM TACH BH SPEED HL Bg BREE ZODM 1 2300 0000 Z A dotted crsr IHITIHL I J K L H H F 28 Press EXIT to enter this value Then press LBF D to activate the label The last parameter that needs to be configured is triggering When using the impact hammer technique the measure ment needs to begin at or before the exact moment of the hammer blow Consequently the analyzer needs to be set up to trigger from channel one on the positive slope of the time domain impulse You also need to establish a delay or pre trigger on channel one so that the entire impulse is cap tured 29 Press EXIT twice to return to the MAIN menu 30 Press T TRIG M from the DISPLAY menu MER Zeidriid H SPECT C SFECT FER COHER TIME DISPLAY note DETECTE LEF ag OPTIMI COUNT MANUAL ACCEPT Lia HE 1Hz 18kHz
305. x a Channel 1 ela z ps ae h DIFF Ph 101 6 Sn 71 96 PES TACH H H SPEED B d s z z e dotted crar IHITIHL T LIHEK 66 HH 1206 Saug 4308 9668 192668 3 Press INT2260 D or INT2250 B to initialize the probe d 297 276 RS INT2258 INT2251 1NT2260 SPL 1 6300 1568 ERF HMEHT IAL 1 8 Dual LIMEHR 25Hz l8kHz STOP 12 IHH 93 28 23 16 FILTER 24 258 Hz LS ee 1 Es os is DIFF Ph 101 6 Sne 71 96 TACH 8 8 SPEED 4 4 dotted crar 24 eB REM 44 INITIAL 4 Press EXIT key 9 Now to program the KEY A to activate the R S hard key T pressthe KEY A D first Ez pics al 75 Z JORE DC out I0 rortC KEV A gt KEV B Beerer ES1 IHT SFL 1 6364 146 fi Sa Re te Sa ie an at ie at Sane MRM AE SRE RE ie dare ce Se tw Ga Ga Sa SE A ate at a de ae AD ae a OB EXPONMENTIGL 1 E Dual LIHERR z 6Hz 1 kHz STOP 12 JAH 93 295 2595 16 ai a o se cay Gur a A DA a T2222 952 5 E FILTER 24 z756 Hz Leo a ee 1 a OPVAL A c TTT DIFF Ph 101 6 Sm 71 96 RER TACH 4H SPEED B El E z z E dotted crar INITIAL T LIHE Su BEB 1246 Z Saba dana 9688 19768 6 Then press the hard key followed by the R S hard key RESET Pressing KEY A on the probe will now remotely activate the R S measurement process in the 2900B eee ee eee ee ee SPL 1 6388 14H A a e EXF HEHT T DL 1 78 Dual LINEAR ZBHz 1BkHz STOP 12 JAN 98 28 22 16 ai erccz4 cz c1 n nz Sos ons S O O FILTER 24 z756 Hz Leo At Channel 1 Qu Z ET 15 MR BB o zz o zo gg
306. y macros Each macro permits the user to define up to fifty sequential key presses and when executed will simu late the manual key press operation of the analyzer SPACE MACRO gt O It is recommended to begin from the Main Menu of the analyzer Press the EXIT hardkey until you have returned to the Main Menu 1 Press the MACRO hardkey to enter the Macro Define mode The message MACRO Select 0 9 or Create STO Store will appear on the upper right side of the display e 23 03 44 CREATE EXPONENTIAL prg Te Dual LIMEBR 28Hz 2BkHz RESET 16 FEB 98 28 43 33 FILTER 31 1 25kHz L 3 a 1 Ea HORMAL a FREE Ph 66 4 Sn 6 28 TACH 8 8 SPEED 4 4 dotted crar 38 ri TRIG JB REM 3B ponFus 2 Press the A minus key to create the macro 9 1 2900B TRAINING MANUAL The message Define MACRO I P will appear on the upper right side of the Display 23 FEB 19 34 16 CREATE 115 r A E act ir Home tar ceris cal O AN E Fs a r jee lato es A aiae H N R R NN Nose a Sees DEF IHE MACRO I P 1 SPL B Bab ab r A NR a A MEA aa El ON MON ue ata da aa a EXPOMENTIAL 18 Dual LIHEHE 2H6Hz 26kHz RESET Z3 FEB 98 19133112 TH r K GMT a ls T cud ar A ate wie a a Saket a FILTER 14 75 8 Hz Leo Channel 1 of 2 HORMAL d 23 8 H 34 9 54 r KMS A O AR nes St car dT Dr Ra T R A A cao A A Mn hn Real er te f DIFF Fhz az n 7 45 REM a A TACH 4 8 SPEED B El 25 5 Hz 636 Hz zH BEHz E dotted

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Larson•Davis