XEQ-3 Service Manual - Sound-Light-Lage
Contents
1. 004084 CAPACITOR 1500 PF 104 100V CER AL A5 A9 A13 A16 A19 004080 CAPACITOR 150 PF 10 100V CER A7 A8 A14 ALS 004022 CAPACITOR 39 PF 10 50V CER 003685 CAPACITOR 470 PF 03330 CAPACITOR 0 022 MFD 10 250V MYLAR 003273 CAPACITOR 0 1 MFD 5 SOV MYLAR 003232 CAPACITOR 0 01 MFD 5 MYLAR 03228 CAPACITOR 0 0082 MFD 54 50V MYLAR CAPACITOR 0 0047 MFD 5 50V MYLAR SEE NOTE 8 106 8156 R273 R278 e6eRe67 EE NUTE 7 RI40R190R244 2718880 2 RESISTOR 10 0K 1 1 4 W MET FILM SEE NOTE 6 SEE NOTE 5 RIOLRISIR204 RISR25 R35 R45 RI6 R26 R36 R46 RS5 R65 275 R85 R56 R66 R76 RBE RI4 R24 R34R44 R54R64R74 RB4 RI3 R23 R33R43 RS3R63R73R83 R10 R29 RGRSRISRISRESKR37 SEE NOTE 4 RSeRGER7BRBE RI2R22 R3BR42 R7 RBR20R27 R17 R30 C74 SEE NOTE 3 C2 C28 C52 073 C85 CI08 CLC3 SEE NOTE 2 C53 Ci4 C17 C76 SEE NOTE _ C5 C amp C75 CS7 C amp 0 C12 C36 001514 CAPACITOR 100 MFD 35V ELEC ALUM RAD 001209 CAPACITOR 22 MFD 10V ELEC ALUM RAD 001121 CAPACITOR 470 MFD 6 3V ELEGALUM RAD E RES 4 0 MPD S VELECALUM RAD DESCRIPTION BILL OF MATERJAL FOR DNE COMPLET 22 C29 C32 C46 C55 C56 C64 C65 C70 C81 C82 C9 C20 C21 C23 C33 C44 C45 C47 C54 C63 C66 C67 C4 C18 C25 C27 C42 C48 C51 C61 C68 C69 C72 R11 R21 R31 R41 R51 R61 R71 R81 R 109 113 117 121 R 159 163 167 1712. 1 P N 2 P N 3 P N 4 P N 5 P N 6 P N 7 P N B P N 9 P N 10 P N 11 P N 12 P N 13 FOR CONNECTOR HOUSING MTS iS6 3 POS 908049 DIDDE SIGNAL N4447 008046 DIODE ZENER 18V 1N4746 IC DUAL QUAD RC4136 IC DUAL 8 PIN NES538 LC DUAL B PIN LF 353N TRANSISTOR NPN MPS8090 G1 62 03 TRANSISTOR PNP PN3645 RESISTOR 4 7 MEG 5 1 4 W CF RESISTOR MEG 5Z 1 4 W CF RESISTOR 68K 5 1 4 V CF RESISTOR 62K 5 1 4 W C F RESISTOR 24K 5 1 4 V CF SEE NOTE H BILL OF MATERIAL CONTINUED RESISTOR 3 24K 1 1 4 W MET FILM 005362 RESISTOR 8 00 1 1 4 W MET FILM 005361 RESISTOR L87K 1 1 4 V MET FILM 005360 RESISTOR 124k 1 1 4 V MET FILM 1 4 V CF 003273 REF 004080 REF 004216 REF 005362 REF 005513 REF 005621 REF 005853 REF 005894 REF 005902 REF 005904 REF 005911 REF 005951 REF SCHEMATIC SEE EV 10 DES DES DES Di D6 D I D13 D18 D19 Dm U 004087 CAPACITOR 0 01 MFD 207 50V CER REFERENCE DES DES DES DES DES DES DES DES DES DES D RESISTOR 1714 174 M MET FILM 005358 RESISTOR 806 17 14 1 4 W MET FILM 004702 CAPACITOR 0 01 MFD 250V UL APPROVED 004216 CAPACITOR 47 MFD 25V ELEC NP RAD
3. Level Controls at Center Detent Unity Adjustment Range re Unity Gain Continuously Variable 12 dB Specifications FREQUENCY RESPONSE SUM OF OUTPUTS LEVEL CONTROLS AT CENTER DETENT 2 000 OHM LOADS 20 20 000 Hz 30 5 dB TOTAL HARMONIC DISTORTION 20 20 000 Hz Typical 0 02 Maximum 0 1 NOISE EACH OUTPUT CONTROLS FLAT 20 20 000 Hz NOISE BANDWIDTH Typical 90 dBu CHANNEL CROSSTALK Typical 78 dB TRANSIENT PERFORMANCE Not limited by slew rate or power bandwidth under normal operating condition 20 20 000 Hz LED LEVEL INDICATORS Level dependent brightness provides enhanced resolution Green Input level above 20 dBu Yellow Input level above 0 dBu Red input or any output level above 16 dBu FRONT PANEL CONTROLS Each Output Gain delay polarity and channel mute CHASSIS CONSTRUCTION Painted aluminum COLORS Black with white graphics MOUNTING Standard 19 in rack panel 1 in high 7 in deep behind panel SUPPLIED ACCESSORIES HP16 32 plug in high pass filter module for 16 or 32 Hz low frequency protection BMK blank plug in module for construction of custom modules smoked acrylic secunty cover OPTIONAL ACCESSORIES EQA EQB plug in equalization modules for flat acoustic response of compression drivers on constant directivity horns see Table 1 for complete list TRB 2 set of t
4. 3 dB peak relative to the on axis level As phase cancellation is frequency dependent changing the crossover frequency will alter the axis orientation Linkwitz Riley filters are termed zero lobing error because the unvoidable cancellation axes are placed symmetrically above and below the system axis Also the system on axis response is flat with no off axis response peaks In Figure 11 the Linkwitz Riley filter does not eliminate the cancellation axis again this is purely a function of two displaced sources reproducing a common frequency However from a design standpoint the lobes are now placed in a much more manageable position consider a typical system orientation with respect to a seating area Commonly the system is aimed near the center of the FIGURE 10 Combined Acoustic Output Using Butterworth Network seating bank From Figure 10 it is obvious that a seating section below the system will experience a hot spot produced by the peaking lobe of a system using a Butterworth design crossover filter Also a seating area above the system axis will experience a dropout caused by the interference along the upper cancellation axis In contrast consider the same conditions using a Linkwitz Riley crossover filter With Linkwitz Riley filter characteristics there is no peaking axis and therefore no hot spots referenced to the system axis In the above example the Linkwitz Riley cancellation
5. LG LG 400923 KNOB BLACK PUSH SWITCH HEATSINK TO 220 THERMALLJY 6043 FUSE 08 AMP SLO BLO 240V FUSE 0175 AMP SLO BLOW 005908 RESISTOR 18K 5 174 V CF 005904 005902 RESISTOR 10K 5 1 4 V CF 005894 RESISTOR 5 1K 5 1 4 V CF 005884 RESISTOR 2 K 5 1 4 V C F 005879 RESISTOR Lek 54 1 4 V CF 005861 RESISTOR 220 S 1 4 W CF 005853 RESISTOR 100 5Z 1 4 W CF 005829 RESISTOR 10 5 1 4 W C F 005817 RESISTOR 3 3 5 1 4 W CF POTENTIOMETER 100K 4 GANG B TAPER lt d 005486 POTENTIDMETER SOK PCB B TAPER ER 005372 RESISTOR 44 2k 47 14 1 4 W MET FILM ANG PC MOUNT RA ADC 4 24028 0180 J3 J5 CONNECTOR MIC JACK RA ADC 4 24027 0150 JI 005371 RESISTOR 301K 1 1 4 W MET FILM 005370 RESISTOR 56 7 1 1 4 W MET FILM 005369 RESISTOR 17 8 1 1 4 W MET FILM 005368 RESISTOR 16 5K 14 1 4 W MET FILM ES h 005367 RESISTOR 14 3K 4 14 1 4 W MET FILM i 005366 RESISTOR 10 7K 1 1 4 W MET FILM 005365 RESISTOR 5 76K 1 1 4 W MET FILM RESISTOR 4 99K 1 1 4 W MET FILM 11300095 CONNECTOR RECEPTACLE 2 PIN AMP 008022 DIODE POWER 1N4002 007014 LC 1 007013 007018 006051 006044 006004 005951 005928 RESISTOR 120K 5X 00591 005909
6. R 210 214 218 222 R2 R5 R108 R111 R112 R115 R116 R119 R120 R123 R126 R133 R158 R161 R162 R165 R166 R169 R170 R173 R176 183 R209 R212 R213 R216 R217 R220 R221 R224 R227 R228 R230 R233 R236 R237 R110 R114 R118 R122 R135 R137 R141 R160 R164 R168 R172 R185 R187 R191 R211 R215 R219 R223 R229 R240 R243 R270 R100 R102 R138 R150 R152 R188 R203 R 205 R241 R255 R275 R277 R134 R136 R139 R184 R186 R189 R238 R239 R242 R259 R253 R261 R272 R274 R276 R279 R103 R104 R153 R154 R206 R207 R250 R252 R256 R258 R263 R265 R268 R269 R105 R107 R124 R155 R157 R174 R225 RAWING NUMBER 301 11 003207 CAPACITOR 0 0015 MFD S7 50V MYLAR C38 C4i E 003201 CAPACITOR 0 001 MFD 5 50V MYLAR C10CLLC13F34C35 C37 001617 CAPACITOR 330 MFD SOV ELECALUM RADIC7ZC78 1 De E A CAPACITOR 1000 MFD 35W ELEC ALUM RAD CE83CB4 E CI9C43 ro c62 i REFERENCE DES E UNIT j t welve 85 MARK IV AUDIO R amp D CENTER TO 6951384 11 29 FROM MAY 93 1995 e oqe 31 ZLWO3 95 UOP S9nIBA 1 9 8 09 yey D3x 34 uroJ yuasayjip p IL EOS SI 4 47 Vb X1W c D3X YIM sunses juajeainba IAH sanjea pajedipuj yuasayjip Anubis sy AGojodo JW 4 Vi XLW S310N lt S SaS 31 28 sueis s obeys dH ZH SJ JO0AA S M IA suajs s abejs dH ZH S19J00M Z1 YM SUu9 SAG 86giS p6LH UO YOLOZHO JO EHO JH waiss azis dH ZH 0f vopas J1 VzIZ S3 U0jD9S JH VZIZ
7. S paKojdui3 ABojodol OF parajia ageonddy Jon asuodsay eJd 95 gW Vp HLW uojpes JW VFHIW uones dH V HLW waysks 41Z 11W UO DSS AW VFG Z H1IN Y PBIZ HLW PO Z HLW UDIPIS JH Vr6 Z H1W Y 6 Z HLW F9 Z HLW SWISAG 47 OSI SWSISAS 41 OSIW SWaAISAS 47 2SIW Sb6dH Y SPO9dH 6dH F9dH DZ dH 0 06dH Y 0b09dH 0Z0bdH 0y9dH O ZLdH OPGdH 0y094H 0Z0P dH 8 OF08dH O SdH Y 0Z dH 0 1dH 0p6dH Y VO 05JH 09JH Y OFHH 0ZLdH 06HH asuodsoy 18 V020P8H Y YOPOBYH Y OZLYH 06JH LUA N 9 VZHO WLHO LWAQ N 8 VZHQ VLHO LWAQIN VZHO WHO LWAGIN Y VZHd WLHO LWAGIN 9 VZHO VLHG LWAQ N VZHO VLHO LHO ZHO LHO ZHO IHQ 3 HO ZHO 9 Ha ZLOZHO ZLOZHO Z OZHO Z 0ZH asuodsey 1814 9081HO ZLOLHO 90SIHQ9 ZLOLHO S0SLHOP ZLOLHO 90S HO ZLOLHG 90SLHOI9 ZLOLHO 4 444 PEL 01 HEEL El MS 36 9 AZ Lp 3 8 3Sv 8 405 405 4 Ay 3051 6 326 1 8b 118p 3 Gb val 1905503 2140139913 D3X 10 SAINPOW D3 uj bnjg xS v8 Se 8 3001 3001 Az Lp 9 HOUMS Cp 3001 X001 4004 3001 001 001 3001 3001 3001 X1 89 3H swajsAs abeis AVVZb2 S4 dH V212 SJ 31V XLW BW VI XLW JW VF 3H Vr 3121Wb3 BW Z1 WO3 dH Z1WD
8. axes are located at 30 relative to the system As the vertical coverage pattern of common high frequency horns is 40 209 the cancellation axes are located beyond the designed coverage area in single horn driver systems Recall from Figure 10 that one cancellation axis for a Butterworth filter is located within the coverage pattern of typical horns From the above examples and illustrations it clear that Linkwitz Riley filter characteristics offer the sound system designer distinct advantages as opposed to Butterworth designs for electronic crossovers In summary Linkwitz Riley filters produce no off axis response peaks and place the inevitable cancellation axes symmetrically above and below the system axis for smoother overall frequency response in the crossover region A more detailed and graphic treatment of the subject is available in a number of technical articles including 1 S H Linkwitz Active Crossover Networks for Noncoincident Drivers J Audio Eng Soc vol 24 pp 2 8 1976 January February 2 S P Lipshitz and J Vanderkooy A Family of Linear Phase Crossover Networks of High Slope Derived by Time Delay J Audio Eng Soc vol 31 pp 2 20 1983 January February 0dB System Axis FIGURE 11 Combined Acoustic Output Using Linkwitz Riley Networks seven XEQ 3 SERVICE MANUAL PC Board elaht Schematic XEQ 3 SERVICE MANUAL NOTES D gt RESISTORS NOTED ARE PART OF
9. each lead close enough to the pin to allow later installation of the cap If you are using conformally coated dipped resistors be sure the leads are free of the coating material where they emerge from the resistor body Be careful not to overheat the pins or the plastic base will melt 4 Check all connections and resistor values 5 Attach the cap with glue 6 Label the module Module Construction Non Standard Crossover Frequencies Output Transformers NON STANDARD CROSSOVER FREQUENCIES The XEQ 3 can be modified to provide crossover frequencies other than the six frequencies available at each switch This is easily done only resistors and a phillips screwdriver are needed if the new crossover frequency is between 80 Hz and 800 Hz for the low mid switch and between 500 Hz and 8 000 Hz for the mid high switch Four 4 watt 1 resistors are needed for each filter switch For a crossover frequency f the following resistor value is needed 1 Low mid filter R 283 x 10 356 x 107 xf 1 98 x 104 x f 1 59 x 108 2 Mid high filter R 4 79 x 10 6 02 x 107 x k 3 21 x 104 x f 1 59 x 107 OUTPUT TRANSFORMERS The outputs of the XEQ 3 can be transformer coupled by adding the optional TRB 2 set of three transformers to the circuit board This should be done by a qualified service technician Remove two screws from each side and the back and lift off the top cover Then remove the five screws holding th
10. which is capable of compensating for different speaker mounting positions and phase responses so that proper acoustic summing will occur at the crossover freguencies Each output also has an EO section controlled by a plug in module The LOW EO can be used as an infrasonic filter or for step down operation of TL bass speaker systems The MID EQ and HIGH EQ are designed to provide constant directivity horn and driver equalization when used with the appropriate module The XEQ 3 is supplied with an HP16 32 module infrasonic filter at 16 or 32 Hz for the LOW EQ and two EQF modules flat response no EQ for the MID EQ and HIGH EQ sections Other modules can be ordered from Electro Voice or custom built using the supplied BMK blank module Other features include a level display for optimizing dynamic range a level control polarity reverse switch and mute switch for each output switches which allow two way crossover operation and floating differential input and outputs Output transformers Electro Voice TRB 2 set of three can be installed if desired The XEQ 3 mounts in one EIA rack space and is supplied with a smoked acrylic front cover to prevent uninvited control adjustment Figure 2 shows the XEQ 3 block diagram CONNECTIONS Input and Outputs The input connector is a 3 pin female XLR type output connectors are 3 pin male XLR type Pins 2 and 3 are signal and each pin 1 is ground This grounding arrange ment works we
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12. Ey Elec Ey ElectroVoice XEQ 3 ELECTRONIC CROSSOVER a gultan company XEQ 3 ELECTRONIC CROSSOVER SERVICE MANUAL XEQ 3 SERVICE MANUAL Table of Contents TABLE OF CONTENTS Page SDecifiGaliDrS 4 2 As AT MS A aie Sig ane AO 2 Pem oo oy eroe A A Ra a AR 3 A SO 3 3 4 ES 4 Custom Eow Frequency Mod les 2s sen ua seais ga tre AA Si aia 4 Module CONSPUCRON uses centre pa V Ys Eats Su Enc Ta E Reels 5 Non Standard Crossover Frequencies 5 CR 5 act 6 ANCA ee dnte esit 7 PO BG uou ARA 8 ER 9 a ds ISA ae be RE 10 SCBEImalib coe Jr SHOES a Nose Due e SE DOVER sets 11 PARDEE dcr redu PEN 12 Neo 13 one XEQ 3 SERVICE MANUAL SPECIFICATIONS CHANNEL CONFIGURATION Monaural three way switchable to monaural two way FILTER TYPE Fourth order Linkwitz Riley 24 dB per octave attenuation CROSSOVER FREQUENCIES SWITCH SELECTABLE See text for other possible frequencies Low Mid 80 125 160 250 500 and 800 Hz Mid High 500 800 1250 1600 5000 and 8000 Hz OUTPUT DELAYS Type Fourth order all pass continuously variable time constant linear control scale Range Low 6 us 0 to 6 ms Mid 1 us 0 to 1 ms
13. GURE 8 Crossover Frequency Modification 00000 00000 dn ii E 4 a 55 2EO he 1848 5005 qa FIGURE 9 Transformer Mounting Locations Jumpers to Cut are Shown as Solid Rectangles Figures XEQ 3 SERVICE MANUAL Linkwitz Riley Filter Advantages LINKWITZ RILEY FILTER ADVANTAGES All contemporary crossover designs maintain predictable acoustic summing in the horizontal plane with vertically aligned system configurations However in the vertical plane common Butterworth designs exhibit a phenomenon termed lobinq error caused by the 90 degree phase shift of outputs and the 3 dB attenuation at crossover To explore the implications of lobing error the following text examines the radiation patterns of systems using a Butterworth filter Figure 10 and a Linkwitz Riley filter Figure 11 In Figure 10 the cancellation axes result from the same acoustic signal of two physically diplaced sources arriving out of phase at discrete locations Consider a typical system with a horn driver combination in vertical alignment with a low frequency system For locations above or below the system axis acoustic signals at crossover frequency will arrive from the horn and woofer at different times due to the path length differences resulting in a phase cancellation at discrete locations The peaking axis represents the discrete locations where the two transducers are exactly in phse and combine to produce a
14. HORN DRIVER ED PLUG IN MODULE EQF SUPPLIED CONTAINS JUMPERS AT POSITIONS 2 amp 7 ONLY gt RESISTORS NOTED ARE PART OF LOW FREQUENCY ED OR HIGH PASS REVERSABLE PLUG IN MODULES HIGH FILTER ROI RO21 RO3 RO4 R012 R022 R032 R042 ROIS R023 RO33 R043 ROM ROM RO34 R044 RO15 R025 55 45 RO16 R026 RO36 RO6 LOW FILTER ROS1 RO6 R071 ROSI ROS2 RO62 ROT2 ROB2 RO53 RO63 R073 R083 RO54 R064 R074 R084 R055 R065 RO75 RO65 ROS6 RO66 R076 ROBE A HIGH CHANNEL nine Schematic EV XEQ 3 SERVICE MANUAL BLLAMHS EXPORT TRANSFORMER CONNECTIONS IN4447 Di2 KEQ 3 SERVICE MANUAL Schematic E E E Q E gu our e c28 JE HE a TRANSFORMERS T2 T3 ARE ACCESSORY ITEMS CONTAINED IN TRE 2 COUPLED OUTPUTS WHEN eleven XEQ 3 SERVICE MANUAL Parts List Notes 484258 TUBING 452503 2 JUMPER ZERO DHM 0 4 452503 JUMPER ZERO OHM 0 6 451163 PC BOARD KNOB BLACK ROTARY 304015 ITCH 4 01 300113 IK 300101 SOCKET DIP 16 PIN RT 7 30009 THEADER 0457 S 3 PIN W LOCK AMP TRANSFORMER POWER EXPORT VERSIONS ER DOMESTIC VERSION T4 SW OTARY NOBLE SR50346B25KC S1SE SWITCH DPDT PUSH ON OFF 53 510 805010 LED amp WIRE S A 500801 RIVET POP BLACK SCREW 4 40 x 1 4 SM PHP TYPE F BLK
15. High 0 3 ps 0 to 0 3 ms INFRASONIC SPEAKER PROTECTION Filter Type Second order Butterworth 12 dB per octave slope Corner Frequencies 16 or 32 Hz provided by supplied HP16 32 plug in module see text for other freguencies EQUALIZATION FOR STEP DOWN OPERATION OF TL BASS SPEAKER SYSTEMS Filter Type Second order underdamped 12 dB per octave rolloff below plus 6 dB peak boost frequency Peak Boost Frequencies 29 35 45 and 60 Hz provided by optional EB29 35 and EB45 60 plug in modules See text for other frequencies EQUALIZATION OF MID AND HIGH FREQUENCY OUTPUTS PROVIDED BY PLUG IN MODULE Normally Supplied EQF module for flat electrival frequency response Optional Modules for Flat Acoustic Response of Compression Drivers on Constant Directivity Horns EQA EQB see Table 1 for complete list INPUT Type Active differential Maximum Level 18 dBu Impedance 20 000 ohms Common Mode Range 24 V net of signa voltage Common Mode Rejection Ratio Typical 55 dB Connector Female 3 pin XLR type MAIN OUTPUTS Type Floating differential TRB 2 set of three isolation transformers available see text Maximum Level 18 dBu Impedance 100 ohms Minimum Load Impedance for Full Output Level 600 ohms Protection Safe for short circuit or 25 volts dc Connectors Male 3 pin XLR type LOW MIX COMMON BASS OUTPUT Impedance 1 800 ohms Connector RCA type phono jack GAIN
16. e circuit board to the chassis and four hex screws from the front panel The circuit board with the front panel attached can then be removed from the chassis Thre are fourteen jumpers which must be removed from the board so that the three transformers will have the proper drive feedback and output connections The jumpers are labeled JP1 through JP14 See Figure 9 To remove a jumper clip the lead at each end and remove the center section The transformer lead layout is asymmetrical so verify the orientation of the transformer leads with the holes in the circuit board before installing Solder all connections on the foil side of the board Reassemble the XEQ 3 in reverse order from the description above five Ev xt 3 SERVICE MANUAL six DELAY IN MILLISECONDS LIL LI Ili 1 LET 1 E LATTE T T FREQUENCY IN MERTZ FIGURE 3 Typical Crossover Curve ESA KUN SAN SS LT LH T Mun ME T CONTROL EHE TN Win rmWoel HH LA EN NII Ht D LIC lia 8 w w m FREQUENCY IN HERTZ FIGURE 4 Low Frequency Time Delay TH hr HITLER BEL i ETE i LI LEE LI HH FREQUENCY i MERTZ FIGURE 5 Mid and High Frequency Time Delay FIGURE 7 Low Frequency Equalization Module Assembly eL INSERT 4 RESISTORS FI
17. hree output isolation transformers POWER REQUIREMENTS 100 120 V ac 60 80 Hz 10 W also available for 80 110 and 220 240 V ac 50 60 Hz OVERALL DIMENSIONS see Figure 1 44 mm 1 73 in high 483 mm 19 0 in wide 185 mm 7 28 in deep NET WEIGHT 3 1 kg 6 8 Ib SHIPPING WEIGHT 3 8 kg 8 4 Ib Ey xeo 3 SERVICE MANUAL Description Connections Control Functions DESCRIPTION The XEQ 3 electronic crossover equalizer is intended primarily for high quality sound systems which require precise crossover filtering and accurate speaker system compensation for optimum frequency and time response The XEQ 3 incorporates fourth order Linkwitz Riley frequency dividing networks which have two unique advan tages over the third order Butterworth networks often used in high performance professional sound systems First a fourth order network offers an out of passband attenuation rate of 24 dB per octave greater than the 18 dB per octave rate of a third order network This provides better protection of drivers from energy outside their frequency range important in some applications Second the Linkwitz Riley network has zero lobing error for smoother overall freguency response in the crossover region This concept is treated in more detail in the section below Each output of the XEQ 3 has a variable time delay egualizer
18. ll in most installations pin 1 can be used as a ground reference or if there is another reference a ground loop is formed then the resistor allows pin 1 to follow the other ground reference A solid chassis ground connection can be obtained at the connector shell The floating differential input and outputs can be unbalanced and referenced to other equipment or they can be connected to balanced lines If a true balanced source or load is needed connect a 300 ohm resistor from pin 2 to pin 1 and another 300 ohm resistor from pin 3 to pin 1 Low Mix The low mix or common bass connection is an RCA phono jack which allows the low output to be mixed with the low output of another XEQ 3 or XEQ 2 This can improve the performance of stereo or multi channel installa tions by equally distributing low frequency energy among the low frequency speakers The low mix connection also allows the use of a single amplifier subwoofer combination in stereo or multi channel systems Any number of crossovers may be used this way by connecting their low mix jacks together When XEQ s are interconnected in the low mix mode any or all of the low frequency outputs may be used These outputs will have a common signal but their individual level polarity mute and delay controls will still function independenily Power A green LED on the front panel indicates when ac power in ON The XEQ 3 may be left on indefinitely or externally switched with o
19. n of Electro Voice TL bass speaker systems The EB29 35 and EB45 60 provide 6 dB of boost at the corresponding peak fre quencies for this purpose Modules can be contructed for other frequencies and high pass filter types see Custom Low Frequency Modules section Mid and High Frequency Equalization The MID EQ and HIGH EQ circuits are identical to each other but are in the mid and high signa paths respectively These circuits will accurately equalize high performance compression drivers used with constant directivity horns The proper EQ module for use with various EV horn driver combinations is shown in Table 1 For applications requiring flat electrical frequency response use EQF modules The XEQ 3 is supplied with EQF modules installed in the MID EQ and HIGH EQ sockets Used With DH1012A DH1506 DH1 DH1A TABLE 1 Horn Driver Egualization Modules CUSTOM LOW FREQUENCY MODULES High Pass Filters Ifa low frequency cutoff other than 16 Hz or 32 Hz js needed a module can be constructed for other fre quencies by soldering resistors into the supplied BMK blank module kit Two resistors are needed for each filter frequency Note that each module can accommodate two frequencies since there are two ways to plug it into the socket One quarter watt film resistors having a resistance tolerance of 1 or 2 are recommended but in less critical applications 5 resistors may suffice Mil type RNSSD resistors are ea
20. siest to use however conformally coated resistors may also be used In the following formulas R and R5 are in ohms and f is the corner frequency in Hz fom 106 x 1013 4 7 x1 X lg x Ri R1 x 4 7 x 106 2 x R 9 4 x 105 For maximally extended low frequency response use Ri 1 megohm and leave R out The fs will then be around 5 Hz to 10 Hz depending on the load impedance Step Down EQ Modules To make modules for step down equalization of low frequency speaker systems use the following formulas The equalization circuit will produce a 6 dB peak at the frequency fp and a 12 dB per octave rolloff below the peak nos 3 11 x 1012 747 x 10 x t 661 x 105 R 4 43 x 105 n EV XEQ 3 SERVICE MANUAL Module Construction In addition to the Electro Voice BMK blank module kit the following items are required 1 Two or four resistors calculated from the formulas given above 2 Low wattage soldering iron with small chisel tip 3 Electronic grade solder 63 37 or 60 40 alloy rosin core 4 Flush cutting diagonal cutters 5 A spare 16 pin DIP socket 6 Adhesive epoxy super glue or hot melt 7 Various hand tools as needed Refer to the diagram in Figure 7 1 Insert the DIP plug into the spare socket or use the one on the XEQ 3 This helps to keep the pins in alignment during soldering 2 Locate pin 1 by the cut off corner on the plug 3 Place and solder the resistors one by one and trim
21. ther equipment CONTROL FUNCTIONS Crossover Frequency The six position rotary switches select the frequencies for the low mid and mid high crossover filters The correspond ing outputs will be 6 dB down at the selected frequency compared to the midband response See Figure 3 The XEQ 3 can be modified to provide other frequencies see Non Standard Crossover Frequencies section Input Level Indicator The level of the input signal to the XEQ 3 is monitored with three LED s The green LED indicates signal above 20 dBu and the yellow LED lights when the signal reaches 0 dBu The red LED lights if the input or any output exceeds 16 dBu In normal operation the yellow LED should light much of the time indicating normal signal level but the red LED should not light Level Controls Each of the three outputs has a level control with a 12 dB range The center detent position is unity gain These controls are intended for fine tuning the system response large differences in speaker output should be approximately compensated with the power amplifier s attenuators and then accurate level matching can be achieved with the XEQ 3 level controls Polarity Reverse Switches These switches will reverse the polarity of the correspond ing output These are used primarily to assist adjustment of the delay control Mute Switches When a mute switch is pressed the corresponding output will be shut off These are useful for setup calibra
22. tion and troubleshooting Time Delay Controls Each output on the XEQ 3 has time delay control which allows compensation for the time and phase response differences which exist in almost all practical multi way speaker setups The delay sections are four pole all pass three XEQ 3 SERVICE MANUAL Control Functions Equalization Custom Low Frequency Modules Time Delay Controls continued filters with continuously variable time constants see Figures 4 and 5 Adjusting a delay control is acoustically equivalent to physically moving the corresponding speaker with respect to the others The delays available may not always be sufficient to compensate for all physical location differences encountered However half wavelength shifts should nearly always be possible thus eliminating the interference cancellations that can occur at crossover Normally only two delay controls are needed in a particular setup the speaker with its acoustic center furthest from the listener should have its delay control left at There may be exceptions to this such as when a certain unusual time response is desired The best way to adjust these controls is by measuring the direct field on axis frequency response using a plotter or a spectrum analyzer reverse the polarity of the output to be adjusted turn the delay control until the deepest possible response null occurs at the crossover frequency then restore the correct polarity The result
23. will be optimum phase and frequency response through the crossover region The delay controls can also be adjusted with just an oscillator set at the crossover frequency by listening for and adjusting for the null on axis and in the speaker system s direct sound field Switching to the correct polarity will then yield flat response Set the level controls first then set the delay controls Two Way Operation The XEQ 3 can easily be set up for two way operation by pressing one of the switches on the back panel Which switch to press LOW MID or LOW HIGH depends on which crossover ferquency range is needed The two corresponding outputs are then used The third output can be used also if another speaker in a stack or cluster needs a different equalization module or control seiting For example by pressing LOW MID and setting both crossover frequency switches to 500 Hz or 800 Hz the mid and high outputs have the same frequency range but separate controls and EQ The possible combinations are shown in Figure 6 EQUALIZATION SECTIONS Low Frequency Equalization The LOW EQ socket accepts plug in modules for different types of high pass filters The HP16 32 module supplied will provide a second order Butterworth maximally flat response with a cutoff frequency of either 16 Hz or 32 Hz depending on which number is right side up when the module is installed Other modules are available for step down operation low frequency extensio
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