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AUDiT™ Software Operation Manual

1. AEC201 Final Assembly for Testing Supra Aural Earphones AUDit Manual The following steps are suggested for audiometer calibration with the AEC201 Step 1 Assemble the coupler as described in AEC201 Ear Simulator and Assembly and Calibration on page 5 12 The coupler base should rest on the isolation pad and ambient noise and vibration should be minimized Step 2 Perform a calibration of the system as described in AEC201 Acoustic Calibration on page 5 15 Step 3 Screw the coupler over the base FIGURE 5 21 until finger tight FIGURE 5 21 Coupler being installed on AEC201 Step 4 Place the black conical ring FIGURE 5 22 on the top of the coupler FIGURE 5 22 Black Conical ring installed on AEC201 AEC201 Ear Simulator and Assembly and Calibration 5 17 Step 5 Center the test earphone on the coupler Lower the black retainer ring over the earphone holding the earphone cable in line with the notch FIGURE 5 23 FIGURE 5 23 Retainer ring being installed on AEC201 Step 6 Lower the mass by its handle to the top of the ear phone FIGURE 5 24 FIGURE 5 24 Mass being lowered onto headphone The coupler and earphone are now ready for measurement Set tone type level and presentation and make the reading on the measurement system AEC201 Final Assembly for Testing Circumaural Earphones Circumaural earphones are available for audiometers using extended high frequencies from 8000 to 16000 Hz These
2. Calibration due 2012 Oct v pi Delete Cancel FIGURE 2 4 Instrumentation Screen Types of instruments are listed in the upper left rectangle Currently defined instruments in this case sound level meters are listed in the rectangle at the lower left The large area at the right has fields for model serial number and other information for each type of instrument If your instrumentation has already been defined for the current database skip forward to the Preferences section If you modify data for an instrument and select Add then a new instrument will be created Update will change the information for the currently selected instrument OK must be selected to commit any changes to the AUDit database Selecting Cancel will discard all changes made using Add Update or Delete Entering Instrumentation AUDit Manual Sound Level Meter Currently the Larson Davis System 824 precision sound level meter SLM is the only SLM instrument compatible with the AUDit software To enter your SLM information click Test Instrumentation and select Sound Level Meters in the upper left box of the screen Enter the serial number of your 824 and its calibration due date both available on labels on the back of the instrument The calibration year must have four digits Once all fields are completed click Add A new SLM entry will appear in the lower left box Calibrator Calibrator information is entered by clicking Test I
3. Once AUDit has been configured with the test instrumentation and audiometer information an actual audiometer calibration may be performed The main measurement screen is accessed from the Setup screen by pressing the OK button Calibration Main Measurement Screen a GSI 1761 0919 AUDit File Test View Report SLM Help cat Ua tha aad B ajm year month day Test Date od Mar 24 Audiometer Welch Allyn GSI 1761 SN 0919 Calibration Technician fda 3 24 2010 Supra aural Insert Circumaural Test Earphones Bone vibrator Speakers Earphones Earphones Hearing Level Pass Frequency Pass Linearity Pass Harmonic Distortion Pass Pulse FAIL Cross Talk Pass Frequency Modulation Pass Narrow Band Level FAIL Broad Band Noise FAIL Speech Go To Measurement Go To Equipment Setup Cancel Done FIGURE 7 1 Main Measurement Screen CER The main measurement screen FIGURE 7 1 allows you to enter the test date and technician name The tested audiometer manufacturer model and serial number are AUDit Manual Frequency Test 7 1 displayed as entered in the previous setup A table of tests and transducers shows the available tests for the particular audiometer For example the Frequency test may be performed with supra aural insert or circumaural earphones Appropriate corrections are applied within each test using appropriate microphone coupler and standard adjustments To continue the a
4. Save Ok Cancel FIGURE 15 1 Speech Test Transducers Screen Speech Test with Earphone Transducers The headers at the top of the table The measured SPL value from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed In this section a supra aural earphone transducer will be calibrated The procedure is the same for insert earphones and is very similar for the other transducers To perform a test of the supra aural earphones highlight the Supra aural Earphone transducer list item One may select which earphone to test by pressing on the Left or Right tab The desired test hearing level is selected at the upper right of the tab in the HL Dial Setting field 15 2 Speech Test with Earphone Transducers AUDit Manual Mic Test Press Measure All to perform a complete speech level test on the left earphone or highlight the Mic line and press Measure Selected AUDit then displays the prompt shown in Figure 15 3 Set Mic 70 dBHL Left i Cancel FIGURE 15 2 Set Level and Frequency Dialog Box The speech material calibration signal should be provided at the microphone input Set the appropriate level input and presentation on the audiometer then press OK The measured SPL is corrected for coupler microphone and other responses and should be 12 5 dB above the 1000 Hz RETSPL for the transducer in use See ANSI S3 6 2004 section 6 2 12 Target SPL is determined f
5. 0 4 0 to 6 0 25 3 32 3 j i 4 0 to 6 0 20 3 27 3 3 x 4 0 to 6 0 15 2 22 2 X 4 0 to 6 0 10 1 17 1 D 4 0 to 6 0 5 2 12 2 q q 4 0 to 6 0 Transducers Circumaural E arphone TDH 39 Earphones Left 2 Right 1 4EC100 Coupler Mic 1316 Measure All Measure Selected Next Test Cancel FIGURE 8 1 Linearity Measurement Screen To perform a linearity test from the main audiometer test status screen follow these steps AUDit Manual Linearity Test 8 1 The SLM should be calibrated before a measurement is performed In this example the supra aural earphone transducers will be calibrated The procedure is the same for insert and circumaural earphones Hint To test only a certain part of the hearing level control linearity First set the upper level in the Max dBHL entry field Then present the lower level on the audiometer during the noise floor test 8 2 Linearity Measurement Screen Step 1 Step 2 Step 3 Step 4 Highlight the Linearity test with the pointer and click the Go To Measurement button If you are already in a test screen press the same test in the Measurements window Highlight the Supra aural Earphone transducer list item The Supra aural Earphone Linearity tabs will appear on the right part of the screen One may select which earphone to test by clicking on the Left or Right tab Select the desired frequency and dial step 10 5 2 or 1 dB from the drop down lists and enter the approp
6. 07 2010 1 Jun 07 2010 da pee GSI 1761 Mar 28 2010 4 FIGURE 17 12 Search Database Dialog Box Entry fields for technician audiometer model serial number calibration from to date and channel number can be used to search for the proper test When all fields are left blank all tests in the current database are displayed To find a certain test enter a search criterion in a field Alphabetical characters are not case sensitive in the search but otherwise search entries must be spelled exactly as they appear in the test Spaces before or after an entry are disregarded Dates 17 10 Stored Measurements Database Functions AUDit Manual may be entered in the following formats Apr 20 2010 or 04 20 10 The To Date must be equal to or later than the From Date Click on Update List to display the search results In the example above entering da 5 28 2010 into the Technician field will display the fourth test on the list Retrieve the test by highlighting it and then clicking on Retrieve at the bottom of the dialog box Delete the highlighted test by clicking on Delete Deleted tests cannot be recalled Booth Test Data The booth measurements available in the current AUDit database can be searched with the dialog box shown in FIGURE 17 13 Audiometric Measurements Booth Test Data Enter customer name booth name and or dates to filter measurement selections Or leave blank for a list of all booth mea
7. 60318 1 2009 Simulators of Human Head and Ear Part 1 Ear Simulator for the calibration of supra aural and circumaural earphones The AEC201 also meets the requirements of the American National Standard ANSI S3 7 1995 R2008 Method for Coupler Calibration of Earphones Section 5 4 With the help of a circumaural adapter plate as described in IEC60318 1 2009 Annex B and ANSI S3 6 2004 Annex C the AEC201 may also serve to calibrate specific high acoustic damping earphones Select the microphone used with the HA 1 coupler This coupler is described in IEC 60126 1973 01 IEC reference coupler for the measurement of hearing aids using earphones coupled to the ear by means of ear inserts The coupler is designed to load the earphone with a specified acoustic impedance when determining the performance of air conduction hearing aids using earphones coupled to the ear from 200 Hz to 5kHz Microphones 3 5 AEC204 Mic Tab Note 126 and 71I have been Select the microphone used with the IEC 60711 coupler replaced by IEC 60318 4 and 5 This coupler is described in ZEC 60711 1981 01 Occluded IEC60711 1981 is canceled and ear simulator for the measurement of earphones coupled to replaced by IEC60318 4 2010 and the ear by ear inserts The standard specifies an occluded IEC 60126 1973 is canceled and ear simulator for the calibration of insert earphones from replaced by IEC 60318 5 2006 100 Hz to 10 kHz Open Air Mic Tab Select the mi
8. The AMC493B converts the force applied by the bone vibrator to an acoustic signal which can then be measured acoustically by the calibration system The following steps are suggested for bone vibrator transducer calibration In addition to the components of the AEC100 or AEC201 you will need the following equipment AMC493B Artificial mastoid MAE100 55 Additional ring mass Environmental conditions The basis for ANSI Standard S3 13 1987 Reaffirmed 1993 Mechanical Coupler for Measurement of Bone Vibrators is IEC 60373 1990 01 of the same name This standard states that in general temperature correc tions can not be used directly to cor rect data not taken at the reference temperature of 23 degrees C as the effect of temperature on the bone vibrator is unknown See also IEC60318 6 2007 5 5 Test Configuration 5 22 Audiometer Test System Assembly Bone vibrator calibration measurements are extremely sensitive to temperature and humidity One important advantage of the AMC493B is its very low thermal mass which allows it to stabilize to the temperature of the test area very quickly typically within a few tens of minutes The sensitivity and mechanical impedance data supplied for the AMC493B were measured at 23 C and 50 RH Although AUDit performs a temperature correction it is recommended to make measurements as close as possible to the temperature at which the AMC493B mastoid was calibrated Except during use
9. The table below shows the actual value of a specific item such as sound pressure for which the level is to be determined First the value is put into expo nential form in powers of ten the exponent is the Bel The exponent is then multiplied by ten to yield the decibel This procedure converts multiplication into addition every time 10 is added to the level the value is multiplied by 10 When the value is not a even multiple of ten the exponent is more complicated as shown in the table Every time the level increases by 3 dB the value is multiplied approximately by 2 doubled These two rules are worth remembering Linear form Level form f Exponential Form of 10 Exponent Ration of Value to Reference F Ratio 1 10 0 10 10 10 100 10 20 200 10 23 1000 10 30 10000 10 40 100000 10 50 1000000 10 60 The definition of decibel is intended for power like quanti ties W Sometimes power is represented by the square of a measured quantity and this results in a different form of the equation See Sound Pressure Level L 10Lo8 wy W W 10 0 The value of the item in the table is not the value of the quantity itself but the ratio of that quantity to a reference quantity So for every level in decibels there must be a refer ence quantity When the quantity equals the reference quan tity the level is zero To keep the values above zero the AUDit Manual Detector E
10. the AMC493B is kept in a case with temperature and humidity meter Place these temperature and humidity number corrections in the AUDit software along with the local pressure to enhance the mastoid accuracy Step 1 Assemble the AEC100 or AEC201 The coupler base should rest on the isolation pad and ambient noise and vibration should be minimized Step 2 Perform a calibration of the system as described in Step 3 Place the coupler over the base FIGURE 5 13 AUDit Manual AUDit Manual Step 4 Lightly place the AMC493B artificial mastoid on the top of the coupler FIGURE 5 29 with ring shaped polymer There must not be any metal to metal contact Press down slightly on the AMC493B to secure its position FIGURE 5 29 Mastoid placed on AEC100 AMC493B Assembly for Testing Bone Vibrators 5 23 Step 5 Center the test vibrator contact surface on the cir cular resilient surface of the AMC493B Ensure that there is no contact between the vibrator body and the AMC493B metallic rim FIGURE 5 30 FIGURE 5 30 Vibrator being placed and centered on mastoid 5 24 Audiometer Test System Assembly AUDit Manual When removing the AMC493B artifi cial mastoid from the coupler gently twist it off to break the seal For more information refer to the AMC493B manual AUDit Manual Step 6 Assemble the additional mass ring over the handle of the AEC100 mass FIGURE 5 31 FIGURE 5 31 Additional mass being placed on AEC100
11. which is a metric equivalent of pounds per square inch To measure sound the oscillating pressure must be separated from the steady barometric pressure with a detector The detector takes out the steady pressure so only the oscillating pressure remains It then squares the pressure takes the time average and then takes the square root this is called rms for root mean square There are several ways this can be done Moving Average The averaging process is continually accepting new data so it is similar to an exponential moving average The equation for it is t ofp ee Tae The sound pressure is squared and multiplied by a exponen tial decay factor so that when the time of integration is near the current time t it is essentially undiminished For times older less than the current time the value is diminished and so becomes less important The rate at which older data are made less influential is expressed by the constant T The larger is it the slower the decay factor reduces and the slower the response of the system to rapid changes These are stan dardized into three values called Time Weighting See the values below Fixed Average The averaging process is over a fixed time period The equation for it is Prms The sound pressure is squared and averaged over a fixed time period Unlike the moving average the sound pressures in all time intervals are equally weighted Sound Pressure Level SPL L p The lo
12. 12000 12500 13000 TANT fki Save RETSPL Cancel FIGURE 3 7 Editing RETSPL Values RETSPL levels are defined by US or international standards Changing levels may result in tests that are no longer compliant To restore RETSPL levels to those defined by these standards click Reset to Defaults Bone Vibrator and Speakers 3 10 Clicking Reset to Defaults will undo any changes you made to RETSPL Clicking Export will launch a Save dialog box to save modifications as a file for future use Clicking Import will launch an Import dialog box import a file of RETSPL values Clicking Save RETSPL will save your RETSPL changes and close the dialog box Clicking Cancel will close the dialog box without saving any changes Information on these two dialog boxes is used to document the measurement and does not affect results Audiometer Test Setup AUDit Manual CHAPTER Booth Test or Ambient Noise Level Test You have now configured AUDit software in preparation for your first test In this chapter the system will be calibrated to perform a measurement of ambient levels in the audiometric test room This is referred to as a Booth test in the AUDit software In doing this test we will also cover connecting to the SLM and calibrating it If ambient noise levels in an audiometric test room are excessively high they can have a masking effect on the sub ject effectively raising the measured hearing thresh
13. 2 4 89 5 gt 70 0 19 5 2 5 lt 17 5 20 0 TDH 50 Earphones Left C 28280 Right C 28281 AEC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Cancel FIGURE 11 1 Cross Talk Measurement Screen To perform a cross talk test from the main audiometer test status screen highlight the Cross Talk test with the pointer and press the Go To Measurement button In this example the supra aural earphone transducers will be tested Highlight the Supra aural Earphone transducer list item The Supra aural Earphone Cross Talk tab will appear on the right part of the screen As with all measurements performed with the tone OFF external vibration or noise may affect the reading The coupler and sound level meter must be on stable surfaces preferably cushioned from room vibration You may observe the display on the sound level meter to verify that the level is Crosstalk Measurement Screen AUDit Manual near the noise floor Press Measure All to begin the cross talk test AUDit displays the prompt shown in Figure 11 2 AUDit A Left Earphone placed on coupler 1000 0 Hz 80 dBHL Right Earphone away from coupler OFF Left Earphone OFF 5 Cancel FIGURE 11 2 Set Level and Frequency Set Dialog Box Set the audiometer to the prompted level and frequency making sure the left earphone is on the coupler and the tone is OFF then press OK There may be a delay while the measurement system acquires a stable
14. 6 2 12 Target SPL is determined from ANSI S3 6 Section 7 2 on the accuracy of sound pressure levels An unsatisfactory reading is indicated by a large red X It may be necessary to adjust the level by pressing the Adjust button Once this is done the input may be retested with the Measure Selected button To perform a speech noise level test on the left earphone highlight the last subtest and click Measure Selected AUDit then displays the prompt shown in FIGURE 15 5 FIGURE 15 5 Speech Noise Level Set Dialog Box The speech material calibration signal should be provided to the appropriate input Set the listed level input and presentation on the audiometer and click OK The measured SPL is corrected for coupler microphone and other responses It may be necessary to adjust the level by pressing the Adjust button Once this is done the input may be retested with the Measure Selected button Tape CD A and Tape CD B Test 15 5 Speech Test with Bone Vibrator Beta Demo AUDit DAR File Test View Report SLM Help Placement Mastoid C Forehead HL Dial Setting 40 Freq Modulation Source Measured FL Hearing Level Deviation Target FL Narrow Band Level Mic Broad Band Noise Tape CD A Tape CD B Speech Noise Transducers Supra aural Earphone Speakers Insert Earphone B71 Vibrator 1 AMC493 Mastoid 2042 NBS 94 Coupler Mic 1316 Humidity T emp Adjust Measure All Measure Selected Next Test Save Can
15. Manual Leave the right earphone on the coupler but present the tone on the left earphone again ensuring that it is occluded and far enough away from the coupler to prevent acoustic cross talk This ends the Cross Talk test The measurements and results are displayed in the tab FIGURE 11 1 For example the first line indicates that the level with presentation in the test Left earphone is 87 1dB SPL while the level measured at the Right earphone with presentation on the non test earphone is 3 1 dB SPL The difference of 90 2dB is 20 2 dB greater than the specification of equal or better than 70GB A subtest which is out of tolerance will be indicated by a large red X A failed subtest may be repeated by highlighting it and pressing the Measure Selected button Follow the same procedure to test any remaining transducers Crosstalk Measurement Screen 11 5 11 6 Crosstalk Measurement Screen AUDit Manual Frequency Modulation Test This chapter describes the Frequency Modulation Test which verifies various parameters of the frequency modulated signals available on some audiometers The Larson Davis audiometer calibration system performs accurate FM measurements of the pure tone signal source by using accurate period measurement techniques The permissible values for this test are listed in Section 6 1 3 of ANSI S3 6 2010 Frequency modulation parameters are measured for the available audiometer frequencies Frequency Mo
16. Microphone Connecting the SLM If AUDit is not active run the software by clicking on the desktop icon or PCB Piezotronics AUDit if AUDit was installed in the default folder Verify communications port options in the Test Preferences RS232 Port tab The Sys tem 824 and Audit must be configured with the same baud rate NOTE The Communications settings on the System824 are accessed by press ae ing scrolling to Communica eee tions and pressing the key Please A refer to the 824 reference manual 1824 01 for complete instructions Turn OFF SLM Set Port FIGURE 4 4 Connect Menu Click SLM Connect to establish connection with the SLM You may verify battery level by clicking SLM Check Battery Figure 4 4 AUDit Manual Connecting the SLM 4 5 SLM Battery Check Battery Level 12 2 EXT FIGURE 4 5 Battery Check Window In this case the battery voltage is 12 2 Volts Figure 4 5 with external power Internal battery status is reported in percent Measurements should not be attempted with inter nal battery readings lower than 10 System Acoustic Calibration NOTE Calibrator and microphone The reference level of the sound level meter is calibrated must be selectecd as shown in the next using a CAL250 or other precision calibrator This instru section before calibration check or ment generates a known sound pressure level SPL relative change to 20 uPa To calibrate click SLM Calibra
17. SLM Gain L 0 Transducer CCondnsr1 Cn al Elctret This would indicate that the noise was not produced in the instrumentation This measurement has demonstrated the ease of use of the Larson Davis audiometer calibration system In the remain der of this manual a full audiometer calibration will be per formed 4 12 Booth Test or Ambient Noise Level Test AUDit Manual Audiometer Test System Assembly The setup defined for each trans This chapter covers test configurations for the audiometer ducer earlier in the AUDit software transducers which can be calibrated by the LD audiometer as described in the Audiometer Test calibration systems The recommended configurations for Setup chapter This will ensure the various earphones will be described first Common elements proper microphone corrections such as the PC to System 824 SLM and PRM902 RETS PL s etc are applied to the preamplifier connections inspection and calibration measurement procedures are explained next Please contact Larson Davis if you have any system assembly questions not covered in this manual FIGURE 5 1 Audiometer Test System AUDit Manual Audiometer Test System Assembly 5 1 Audiometer Transducer Test Configurations Supra aural earphone Circumaural earphone Circumaural earphone Bone vibrator Speakers Insert earphone The table below lists some typical audiometer transducers many of which are covered in specific
18. Set Preferences Menu AUDit Manual Preferences 2 13 Two system setup items are available in the rectangular area at the upper left of the screen as shown in FIGURE 2 13 Organization and RS232 Port File Test View Report SLM Help System setup items Calibration Facility Name FRS232 Port Name Larson Davis Division 1681 West 820 North Provo UT 84601 J Show Dialog to save data when changing test or transducer IV Always Save data when changing test or transducer IV Show waming when Earphone is incompatible with coupler IV Show waming when there is no RETSPL defined for a given frequency IV Display frequencies when there is no RETSPL IV Display Ears Not Covered column for Booth Tests Ok Cancel FIGURE 2 13 Preferences Dialog Box Organization e Click in the Name fields to enter information such as name and address This information will appear on the report and calibration certificate e Checking the Show Dialog to save data when changing test or transducer option will cause the Save dialog box appear before each change You can also click the Save button on e Checking the Always Save data when changing test or the test panel when you wish to save transducer option will cause the data to be saved auto data matically for each change without a Save dialog box prompt e Checking Show warning when Earphone is imcom patible with coupler option will cause a warning mes sage to appear when
19. appropriate level and frequency then press OK Each frequency will be tested until all have been measured consecutively Frequency measurement is performed accurately by a dedicated counter in the Model 824 sound level meter A number of counter values are compared to ensure an accurate reading This process may take a few seconds In this example all frequencies higher than 750 Hz are out of tolerance FIGURE 7 4 This is indicated by a large red X next to each frequency GSI 1716 5804 AUDit DER File Test View Report SLM Help Measurements Frequency Accuracy Hearing Level Linearity Distortion Dial Frequency Measured Frequency Deviation Target Frequency esp 125 124 3 07 123810 126 2 Freq Modulation 250 249 1 0 9 247 5 to 252 5 Narrow Band Level 500 497 5 2 5 495 0 to 505 0 Broad Band Noise 750 745 7 4 3 742 5 to 757 5 Speach 988 7 11 3 990 0 to 1010 0 1484 9 15 1 1485 0 to 1515 0 1975 0 25 0 1980 0 to 2020 0 2964 0 36 0 2970 0 to 3030 0 3951 0 49 0 3960 0 to 4040 0 Transducers 5932 0 680 5940 0 to 6060 0 Supra aural E ar Insert Earphone Circumaural E arphone TDH 50 Earphones Left 2 Right 1 4EC100 Coupler Mic 1316 Measure All Measure Selected Next Test FIGURE 7 4 Frequency Test Results Box 7 4 Frequency Test with Earphone Transducers AUDit Manual NOTE Jf the frequency reading is not A failed frequency may be retested after adjustment by stable it could be due to noise that is highlightin
20. are out of toler ance will be in parentheses and the failed test is indicated by a large red X Pulse Measurement Screen 10 3 10 4 Pulse Measurement Screen AUDit Manual Cross Talk Test Cross talk measurements performed by the AUDit audiometer calibration system are implemented at a chosen frequency for both earphones Crosstalk is defined as an unwanted acoustic signal present on the channel which is not active AUDit evaluates the difference between the level of the driven test earphone and the non driven earphone see ANSI S 3 6 2004 Section 5 4 2 1 item 2 Another test performed in this portion of the software is the audiometer on off ratio This test verifies the output from the left earphone when the tone switch is in the OFF position is no more than 10 dB above the Reference Equivalent Threshold In this case the hearing level control is set at 80 dBHL and the frequency to 1000Hz see ANSI S3 6 2004 Section 7 5 2 Cross Talk Test 11 1 Crosstalk Measurement Screen a GSI 1761 0919 AUDit File Test View Report SLM Help Measurements Hearing Level Frequency Linearity Distortion Pulse Freq Modulation Narrow Band Level Broad Band Noise Speech Transducers p Insert E arphone Circumaural E arphone DER Cross Talk Test Frequency 1000 0 Test Left to Right Right to Left On Off Ratio Tone On Tone Off Difference ANSI Limits Deviation 87 1 3 1 90 2 gt 70 0 20 2 87 1
21. audiometer test status screen highlight the Pulse test with the pointer and press the Go To Measurement button If you are already in a test screen press the same test in the Measurements window Highlight the Supra aural Earphone transducer list item The Supra aural Earphone tab will appear on the right part of the screen The test is nominally performed on the left earphone 10 2 Pulse Measurement Screen AUDit Manual Click Measure All or highlight the first line and press Mea sure Selected to perform a pulse test on the left earphone AUDit then displays the prompt shown in Figure 10 2 A Set PULSED 110 dBHL or max level Left at 1000 0 Hz FIGURE 10 2 Level and Frequency Set Dialog Box NOTE The On Off Time limits in sec tion 7 5 4 of ANSI S3 6 2004 are based on a 2 Hz pulse rate If the audiometer being tested is using a different pulse rate then the pulse on off time measure ments will likely fail If the on off time is the only part of the pulse test that fails a note can be added to the certification paragraph stating that the audiometer is in compliance with the exception of the on off times AUDit Manual Set the audiometer to the prompted pulsed level and fre quency then press OK You may observe an overload on the sound level meter in which case the level should be reduced until the overload disappears The results of the pulse measurement are listed in the tab Figure 10 1 in milliseconds Values which
22. before using the mastoid Mastoid and microphone sensitivities are used to calculate the output level of the bone vibrator Microphones 3 4 a GSI 1761 0919 AUDit File Test Yiew Report SLM Help 2 Setup Items Audiometer Earphones Bone Vibrator Speakers Select Microphones AECIOI Mic AEC201 Mic AEC102 Mic AEC103 Mic AEC104 Mic Open Air Mic Serial Number 2575 Manufacturer _ Larson Davis Calibration Due 2012 01 01 Sensitivity FIGURE 3 4 Select Microphone Dialog Box Audiometer Test Setup AUDit Manual AEC100 Mic Tab AEC201 Mic Tab AEC202 or AEC203 Mic Tab AUDit Manual Microphones FIGURE 3 4 allow you to configure the microphone paired with each coupler If a specific coupler will not be used in the audiometer calibration no data entry is required Select the microphone used with the NBS 9A coupler This coupler was originally developed by the National Bureau of Standards now called the National Institute of Standards and Technology NIST It is specified in American National Standard Institute Specifications for Audiometers S3 6 2004 for calibrating earphones used in audiometry The Larson Davis AEC100 artificial ear is designed to meet the requirements of this standard Select the microphone PCB 377A 13 used with the AEC201 This coupler is designed to achieve the characteristics defined in International Electrotechnical Commission IEC
23. button to disable all tests Clicking OK accepts used Otherwise if the option is the currently enabled selections and clicking Cancel aborts checked the message Includes non the report standard RETSPL will appear on Once you have selected OK the report preview screen the first page of the report displays the selected data approximately as it will appear on the printed page FIGURE 17 3 The paper size and orientation are those selected in File Printer Setup 17 2 Printing Reports AUDit Manual Andiometer Calibration Welch Allyn GSI 1761 S N 0919 PCB Piezotronics Larson Davis Division 1681 West 820 North Provo UT 84601 Calibration Date 2011 09 08 Technician AEC201 AMC493B 5417 Electret Customer Larson Davis Bench Provo UT Audiometer Manufacturer Welch Allyn Model Number GSI 1761 Type 1 Serial Number 0919 Inventory 002139 Number of Channels 1 Channel Tested 1 Earphones Supra aural Insert Circumaural Manufacturer Telephomics EARtone Sennheiser Model Number TDH 50 49 3A HDA200 Right S N 1 1 1 Left SN 2 2 2 Bone Vibrator Manufacturer Model Number Serial Number Speakers Manufacturer Model Number Serial Number Instrumentation Manufacturer Model Serial Number Cal Due Sound Level Meter Larson Davis 824 2431 2012 10 31 Preamp Larsou Davis PRM902 1234 2012 10 28 Calibrator Larson Davis CAL250 1234 2012 11 31 Mastoid Larson Davis AMC493B 5417 2012 10 29 Open Air Mic Larsou Davis 2575 1316 2009 04 1
24. earphone may be retested after replacement audiometer adjustment by selecting it and clicking the Measure All button Follow the same procedure to test the remaining transducers 14 4 Broad Band Masking Measurement Screen AUDit Manual Speech Test This test verifies the calibration of audiometers which offer the facility for playback of standardized prepared speech signals Speech signals may be provided from a microphone tape or compact disc recording input electrically to the audiometer AUDit performs level tests on microphone tape CD inputs A and B as well as internally generated speech noise signals Speech Measurement Screen To perform a speech test from the main audiometer test summary screen highlight Speech Test with the pointer and click the Go To Measurement button Appropriate corrections are applied by AUDit within each test using microphone coupler and transducer data sheets and tables Speech Test 15 1 Beta Demo AUDit File Test View Report SLM Help Freq Modulation Source Narrow Band Level x Mic Broad Band Noise x Tape CD A XTape CD B x Speech Noise Transducers D Bone Vibrator Speakers Insert Earphone HL Dial Setting zo Measured SPL Hearing Level Deviation Target SPL 83 4 63 4 66 87 0to 93 0 83 0 63 0 7 87 0 to 93 0 83 2 63 2 6 87 0 to 93 0 96 3 76 3 87 0 to 93 0 TDH 50 Earphones Left 1 Right 1 4EC100 Coupler Mic 1316 Adjust Measure All Measure Selected Next Test
25. eee ec eeeeeeeeeeeeeeeeneeeees 5 21 Hearing Level Test 6 1 Calibration Main Measurement Screen cceeccecceesseesseceececeseeeneeeeecaeceneecenee ens 6 1 Frequency Test with Earphone Transducers cesccesseceececeseeeseceerecsaeceneeceneeens 6 2 IAUDIT 01 Rev Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Appendix A Frequency Test Calibration Main Measurement Screen Frequency Test with Earphone Transducers Linearity Test Linearity Measurement Screen Distortion Test Harmonic Distortion Measurement Screen Pulse Test Pulse Measurement Screen Cross Talk Test Frequency Modulation Test Narrow Band Level Test Narrow Band Level Test with Earphone Tr Narrow Band Level Test with Speakers Broad Band Noise Masking Test Broad Band Masking Measurement Screen Speech Test Speech Measurement Screen Speech Test with Earphone Transducers Mic TESt resies eroe opne ieee e s Tape CD A and Tape CD B Test Speech Test with Bone Vibrator Speech Test with Speakers Audiometer Test Notes Audiometer Test Notes Screen Reports and Data Base Functions Printing Reports Printing a Certificate Exporting Data Stored Measurements Database Functions Glossary ansducers AUDit Manual Welcome to AUDit Audiometer Intelligent Testing The Larson Davis audiometer calibration system has been d
26. errors PCB Piezotronics Inc will periodically update the material for inclusion in new editions Changes and improvements to the information described in this manual may be made at any time Recycling PCB Piezotronics Inc is an environmentally friendly organization and encourages our customers to be environmentally conscious When this product reaches its end of life please recycle the product through a local recycling center or return the product to PCB Piezotronics Inc Attn Recycling Coordinator 1681 West 820 North Provo Utah USA 84601 1341 where it will be accepted for disposal Warranty For warranty information refer to our Terms and Conditions of Sale on our website at www larsondavis com TermsConditions aspx Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Table of Contents Welcome to AUDit Audiometer Intelligent Testing 1 1 Formatting Conventions cece eeecseeesececsseesececeseceeceseeseseaeeseeeaecneesaecaeesaeaeens 1 2 Unpacking and Inspection xe yes resessie nenese e iiien Tavie S rE 1 2 Software Installation oo eee csseeseeeeeecceseeeeeeseecsecaeesaecsaesaeaecsceseseeeseeseeseaeeees 1 7 Starting the Softw ates resonis cscees esac ses eens Leek cok he EEE a E che EEA eE Eeo 1 8 Initial Configuration 2 1 Creating a Database o icis cisisce sscecesssesiehi aces eecsesneghseevhseusesecedss oth ssesyseuvesses EEr e EEST 2 1 Entering Instrumentation 00 ceeceseeseceseeeecee
27. more than just sound The motion of a microphone diaphragm is in response to a force acting on it The force can be caused by a number of sources only one of which are we interested sound Non sound forces are 1 direct physical contact such as that with a finger or a raindrop 2 those caused by the movement of air over the diaphragm such as environ A 7 A 8 mental wind or blowing 3 those caused by vibration of the microphone housing and 4 those caused by strong electro static fields Rules 1 Do not permit any solid or liquid to touch the microphone diaphragm Keep a protective grid over the diaphragm 2 Do not blow on a microphone and use a wind screen over the microphone to reduce the effect of wind noise 3 Mount microphones so their body is not subject to vibra tion particularly in direction at right angles to the plane of the diaphragm 4 Keep microphones away from strong electrical fields A microphone measures forces not pressures We would like the microphone to measure sound pressure force per unit area instead of sound force If the pressure is applied uni formly over the microphone diaphragm a simple constant the diaphragm area relates the two but if the pressure var ies across the diaphragm the relationship is more complex For example if a negative pressure is applied on one half the diaphragm and an equal positive pressure is applied to the other half the net force is zero and essentially no m
28. on where f is the fundamental frequency fp the first harmonic etc Levels must be expressed in linear units in this formula AUDit Manual Distortion Test 9 1 Harmonic Distortion Measurement Screen a GSI 1761 0919 AUDit File Test View Report SLM Help Harmonic Distortion Fund 2nd 3rd 4th Sth THD Devi Max 1218 738 731 468 615 06 493 25 Free Moi 167 675 678 376 578 05 20 25 Natrow Band Level 1231 770 751 442 616 06 413 25 Broad Band Noise 1076 564 577 232 425 04 a 25 Speech 1066 543 547 187 34 O4 21 25 1064 526 507 209 321 03 22 25 1084 549 539 224 03 22 25 1078 573 364 155 336 03 22 25 1084 561 436 21 O02 23 25 Transducers fae ae Se oe gt 24 25 ie Ft lt w fF 21 25 Bone Vibrator Insert Earphone Circumaural Earphone TDH 50 Earphones Left C 28280 Right C 28281 AEC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Ok Cancel FIGURE 9 1 Harmonic Distortion Test Screen To perform a distortion test from the main audiometer test status screen highlight the Harmonic Distortion test with the pointer and press the Go To Measurement button If you are already in a test screen FIGURE 9 1 press the same test in the Measurements window The SLM should be calibrated before a measurement is performed On the left below the Measurement table the Transducers list contains supra aural earphone bone vibrator insert and circumaural earphones All types of ea
29. port with AUDit e CBL006 serial cable e System 824 precision sound level meter NOTE The _ microphone preamp e EXA010 extension cable optional assembly may be suspended or supported Aa with a suitable microphone clamp If the PRM902 preamplifier dimensions or construction of the audio e 2575 microphone metric test room require a longer length of cable or the use of patch panels care e ADPO08 1 2 inch preamp to 1 inch microphone thread must be taken not to introduce ground adaptor loops or other problems which can lead t higher spiteniseli noise levels e CAL250 precision Sound Pressure Level calibrator 4 2 Booth Test or Ambient Noise Level Test AUDit Manual Assembling the system Step 1 Connect the CBL006 from the SERIAL connector on the butt plate of the 824 SLM to an active serial port on the computer FIGURE 4 1 Connecting CBLO006 to 824 AUDit Manual Assembling the system 4 3 Step 2 Install the PRM902 microphone preamplifier directly on the SLM or use the EXA010 extension cable by matching red dots on opposite gender connectors FIGURE 4 2 Connecting EXA010 extension cable to 824 and PRM902 Step 3 Thread the ADP008 onto the PRM902 preampli fier being careful not to strip the threads 4 4 Booth Test or Ambient Noise Level Test AUDit Manual Step 4 Thread the 2575 or other microphone onto the PRM902 preamplifier being careful not to strip the threads FIGURE 4 3 Connecting PRM902 ADP008 and 2575
30. table 1 of the standard NOTE ANSI S3 6 2004 pure tone Type I and 2 audiometers must have a facility for presenting a frequency modu lated tone Low Frequencies Tab High Frequencies Tab e Audiometer Type Enter the audiometer type number which should be stated in the audiometer specifications or labeled on the instrument itself Additional suffixes for high frequency speech or free field equivalent are not available but may be entered in the Audiometer Test Notes comments e Carrier Frequency Modulation Rate Of Enter the audiometer s frequency modulation percentage and rate of modulation These values will be verified in the appropriate test The Low Frequencies tab allows you to specify which audiometer frequencies will be tested It contains a list of audiometer frequencies from 125 to 8000 Hz The High Frequencies tab allows you to specify which high frequencies available on the audiometer will be tested These frequencies are used by extended high frequency pure tone audiometers Earphones Screen 3 8 AUDit uses the supra aural earphone reference equivalent threshold sound pressure levels RETSPLs in dB re 20 micropascals for common earphones as listed in Table 6 of ANSI S3 6 2004 The RETSPLs referred to the appropriate coupler are used in the calibration process In the case of insert earphones The RETSPLs listed in Table 7 of ANSI S3 6 2004 are used Circumaural earphones interim RETSPLs listed in Table
31. tabs Left and Right In this example the supra aural earphone transducers will be calibrated The procedure is the same for insert and circumaural earphones To perform a test of the supra aural earphones highlight the Supra aural Earphone transducer list item The Supra aural Earphone Frequency Accuracy tabs will appear on the right part of the screen One may select the test earphone by pressing on the Left or Right tab The list of the active frequencies selected earlier in the audiometer setup process appears in the right window Note the headers at the top of the table The dial and measured frequency value from the sound level meter are displayed and the deviation from the target frequency is displayed for each frequency The row of buttons at the bottom of the screen allows the technician to e Measure All measure all frequencies sequentially with software prompts e Measure Selected measure only the currently high lighted frequency with software prompts e Next Test move to the next measurement in the Mea surements list in the upper left window e OK end the current test e Cancel cancel the current test Press Measure All to perform a frequency test on the left earphone AUDit then displays the prompt shown in FIGURE 7 3 for the first frequency A Set 80 dBHL for max level Left at 125 Hz E Cancel FIGURE 7 3 Set Level and Frequency Dialog Box Frequency Test with Earphone Transducers 7 3 Set the
32. weight Step 7 Lower the black retainer ring over the vibrator holding the vibrator cable in line with the notch FIGURE 5 32 FIGURE 5 32 Retainer Ring being placed over vibrator AMC493B Assembly for Testing Bone Vibrators Step 8 Lower the mass on top of the vibrator by its handle FIGURE 5 33 FIGURE 5 33 Artificial ear with vibrator and mass installed The coupler and vibrator are now ready for measurement Set tone type level and presentation and make the reading on the measurement system B amp K 4930 Assembly for Testing Bone Vibrators Unlike the LD AMC493B the Briiel amp Kj r artificial mastoid uses an accelerometer to measure the bone vibrator output The LD audiometer calibration system can interface with the B amp K mastoid by using the high input impedance PRM902 preamplifier and a suitable adapter If the cable from the B amp K 4930 has a 10 32 microdot connector small threaded coaxial connector use the optional ADP007 On the other hand if your artificial mastoid has a BNC coaxial connector use the ADPO06 provided with the LD system You will also need the following Pan None AUDit software running on a PC CBLO006 Serial cable 8 pin mini DIN to DB 9 5 26 Audiometer Test System Assembly AUDit Manual CAL250 Precision SPL calibrator with 114 dB SPL output at 250 Hz B amp K 4930 Artificial Mastoid and accessories Microdot to 1 2 preamp adapter for charge coupled accelerome ter o
33. 1 0919 AUDit Dja tha Bajm 2 Booth Ambient Levels Measurement Test Information SL Meter Preamp Mic Calibrator 125 8K Hz 250 8K Hz 500 8K He M Show Fail G Test Name HVAC off ambient Saano ANa C Show OSHA C Show Both Qute Tech 1 Customer Name The Borland Clinic fi Clinic Circle Anytown PE 19874 Measurement Date 7 28 2011 11 05 30 Measure All FIGURE 4 7 Both Ambient Levels Measurement Screen The first five tabs Test Information SL Meter Preamp Mic and Calibrator are used to document the measurement Choose the measurement instrumentation and enter the mea surement descriptive text The measurement instrumentation available for selection is defined in Test Instrumentation The last three tabs are for displaying test results After selecting the equipment used for the ambient test click Measure All to begin the test 4 8 Booth Test or Ambient Noise Level Test AUDit Manual Ambient Measurement Averaging Sample 5 out of 10 NOTE A message Figure 4 10 will FIGURE 4 8 Ambient Level Test Message Window be displayed while the measurement is performed 125 8K Hz 250 8K Hz and 500 8K Hz and OSHA Tabs GSI 1761 0919 AUDit File Test View Report SLM Help wa a B Bea e Booth Ambient Levels Measurement Test Information SL Meter Preamp Mic Calibrator 125 8K Hz 250 8K Hz 500 8K Hz 4 gt IV Show Fail Frequency Measured SPL Ears Covered M
34. 10 377A13 PRM902 CAL250 or CAL200 10 foot extension cable with 7 pin LEMO connectors 1 2 precision air condenser random incidence microphone 1 2 diameter low noise microphone preamplifier Precision SPL calibrator with 114 dB SPL output at 250 Hz with 1 to 1 2 calibrator opening adaptor ADPO19 The following are AEC201 components AEC201 F AEC100 06 AEC201 2 MAEC100 08 MAE100 6 MAEC100 7 SAEC100 01 ACCO001 Artificial ear base including base contacts insulator and pad Coupler Type 1 adaptor optional Type 2 adaptor Conical ring Earphone retainer ring Mass handle screws into SAEC100 1 Weight assembly and rubber no handle Vibration isolation pad Audiometer Test System Assembly AUDit Manual AEC201 Initial Assembly WARNING Before continuing ensure that the 824 SLM is turned off The 824 should remain off until the system is fully assem bled The AEC201 artificial ear is a versatile coupler and allows measurement of a variety of earphones with its provided accessories Read the following instructions to unpack inspect and assemble the coupler for the first time Step 1 Place the cushioned vibration isolation pad on a table or other such stable surface near the audiom eter system Step 2 Visually inspect the coupler for gouges scratches and dents which may affect the measurement especially around the sharp lip which will be in contact with the test earphone Verify that the small tube i
35. 3 AEC101 Mic Larsou Davis 2559 3157 2012 01 01 AEC100 Mic Larsou Davis 2575 1316 2012 01 01 AEC104 Mic Larsou Davis 377A13 118894 2010 11 18 AEC102 Mic Larsou Davis 2559 3157 2012 01 01 AEC103 Mic Larsou Davis 2559 3157 2012 01 01 Supra sural Bone Circumaural Test Name Earphones Vibrator Hearing Level Pass Pass Frequency Pass NA Linearity Pass NA Harmonic Distortion Pass Pulse FAIL NA Cross Talk Pass NA Frequency Modulation Pass NA Narrow Band Level Pass NA Broad Band Noise FAIL NA Speech Pass FIGURE 17 3 Print Preview Screen AUDit Manual Printing Reports 17 3 Note that the cursor now has the shape of a small magnifying glass and may be used to zoom in on portions of the page Printing a Certificate It is often desirable to provide a customer with a single page certificate after performing an audiometer calibration or booth test service AUDit features certificate printing including a custom header and a paragraph which can be used for standard or test specific text The certificate includes the date on which the test was performed as well as the Issued Date FIGURE 17 4 shows the buttons for viewing and printing certificates AD i Next Page Pre i Two Page Zoom In Close ee Cal a ee ie e lane Dera Domica an vsem ree Pma ra FIGURE 17 4 Print Certificate To print a certificate ensure a new or recalled test is active then select Report Certificate on the main m
36. 50 ms e On Time time in milliseconds between successive 5 dB points of the envelope of the pulsed signal during which the signal is present nominally between 190 and 260 ms e Off Time time in milliseconds between successive 5 dB points of the envelope of the pulsed signal during which the signal is absent nominally between 190 and 260 ms e Width duration in milliseconds of the plateau during which the signal is within 1 dB of its nominal value e On Off Ratio ratio of the maximum level during the OFF portion of the pulse between the 20 dB point of the falling and rising edge of the envelope to the maxi mum level in the ON portion nominally greater than 20 dB Pulse signal envelope characteristics are measured at a nom inal frequency of 1000 Hz by AUDit However the mea surement may be made with another available pure tone frequency AUDit Manual Pulse Test 10 1 Pulse Measurement Screen a GSI 1761 0919 AUDit Measurements Hearing Level Frequency Linearity Distortion Frequency Rise Time Fall Time On Time Off Time Plate On Off Ratio mE 1000 34 0 360 2115 1860 1820 OK Freq Modulation Narrow Band Level Broad Band Noise Speech Transducers Insert Earphone Circumaural E arphone TDH 50 Earphones Left C 28280 Right C 28281 AEC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Cancel FIGURE 10 1 Pulse Test measurement Screen To perform a pulse test from the main
37. 80 5to 86 5 76 0to 82 0 74 5to 80 5 74 5to 80 5 76 0to 82 0 78 5to 84 5 79 0to 85 0 81 0to 91 0 80 5to 90 5 TDH 50 49 Earphones Left 2 Right 1 AEC201 Coupler Mic 118894 Adjust Measure All Measure Selected Next Test Save Cancel 01 08 2013 09 15AM NmMm FIGURE 6 5 Hearing Level Test It may be desired to adjust this level by pressing the Adjust button A small dialog box is then displayed where the technician may select the current frequency and adjust the level potentiometer of the audiometer to fall within the listed target SPL range Hearing Level Test AUDit Manual Adjust Level Measured SPL dBHL Frequency 730 eoo feoooo FIGURE 6 6 Adjust Level Dialog Box Once this is done the failed frequency may be retested with the Measure Selected button Hearing Level Test with Bone Vibrator Hearing Level Bone Vibrator Levels T Use defauts aevi ho sam Set to defauts Bone vibrator input levels Freg Modulation aes Narrow Band Level 250 Broad Band Noise Speech 315 Transducers Supra aural Earphone Speakers Insert Earphone Circumaural Earphone J233 Vibrator 0445 AMC493B Mastoid 5417 4EC103 Coupler Mic 118894 T 0 0C P 760 0mmHg H 30 Humidity T emp Adjust Measure All Measure Selected Next Test Save Cancel 01 15 2013 11 39AM NUM FIGURE 6 7 Hearing Level Test with Bone Vibrator Screen AUDit Manual Hearing Level Test with B
38. AEC100 Coupler Mic 1316 Measure Al Measure Selected Next Test Save Cancel FIGURE 8 3 Noise Floor Test Results Screen A failed level may be retested after adjustment by highlighting it and clicking the Measure Selected button Step 6 Follow the same procedure to test the other ear phone AUDit Manual Linearity Measurement Screen 8 3 Linearity Measurement Screen AUDit Manual CHAPTER Distortion Test Accurate distortion measurements of the pure tone signal source are performed by using narrow band fast Fourier transform FFT analysis Distortion can affect audiometric evaluations and may indicate hardware problems The maximum permissible levels in percent are listed in Table 3 of ANSI S3 6 2010 In general total harmonics should be less than 2 5 for air conduction and less than 5 5 for bone conduction Harmonic distortion is measured at the level listed in ANSI 3 6 Table 4 or the maximum hearing level of the audiometer whichever is lower Limitations in the frequency response of the measurement system dictate that distortion measurements above 5000 Hz should be made across the electrical terminals of the transducer The ADPO10 Audiometer Earphone Testing Adaptor is ideal for this purpose Insert it in the connection to the transducer and then connect its BNC to the ADPO06 BNC to 1 2 preamplifier adaptor on the PRM902 Total harmonic distortion is defined as follows THD percent 100 Fai 8
39. Audiometer Calibration System Manual ARSON DAVIS A PCB PIEZOTRONICS DIV Larson Davis Audiometer Calibration System Manual IAUDIT 01 Rev J Copyright Copyright 2015 by PCB Piezotronics Inc This manual is copyrighted with all rights reserved The manual may not be copied in whole or in part for any use without prior written consent of PCB Piezotronics Inc Trademarks PCB isa registered trademark of PCB Piezotronics Inc LEMO is a registered trademark of LEMO SA LEMO USA is a registered trademark of INTERLEMO HOLDING USA Microsoft Access and Microsoft Excel are either registered trademarks or trademarks of Microsoft Corporation in the United States and or other countries B amp K BK and Bruel amp Kjaer are registered trademarks of Bruel amp Kjaer Sound amp Vibration Measurement A S Disclaimer The following paragraph does not apply in any state or country where such statements are not agreeable with local law Even though PCB Piezotronics Inc has reviewed its documentation PCB Piezotronics Inc makes no warranty or representation either expressed or implied with respect to this instrument and documentation its quality performance merchantability or fitness for a particular purpose This documentation is subject to change without notice and should not be construed as a commitment or representation by PCB Piezotronics Inc This publication may contain inaccuracies or typographical
40. C1 are used by AUDit Contact Larson Davis for information on enabling additional earphones with the manufacturer s valid RETSPL data Audiometer Test Setup AUDit Manual Use the Select Earphones dialog box FIGURE 3 6 to specify the audiometer earphones information and the respective artificial ear couplers used in the test setup File Test View Report SLM Help ifort teal was Bl Ele e Setup Items Select Earphones Test Location Equipment Insert Circumaural Microphones Audiometer Model TDH 39 Bone Vibrator Meta Co oni Speakers E RETSPL Only use this button if you Right Serial Number 1 need non standard RETSPL Left Serial Number 2 Edit RETSPL Coupler AEC100 IEC 60318 3 Allow use of coupler with an AEC101 IEC 60318 1 earphone that has not been certified for that coupler AEC201 IEC 60318 1 Cancel FIGURE 3 6 Select Earphones Supra aural Tab On this tab you can also modify RETSPL values Click the Edit RETSPL button to display the RETSPL Editing dialog box AUDit Manual Earphones Screen Enter your own Reference Equivalent Threshold Sound Pressure Levels You only need to provide values for frequencies for which your audiometer will be tested 31 5 J0 800 63 1000 1250 1500 1600 2000 2500 3000 3150 4000 5000 PT 6000 15 5 6300 0 8000 13 m High Frequency 9000 10000 11000 11200
41. Freq Input Level tabs the speaker test levels can be specified for audiometric frequencies from 125 to 20000 Hertz Use the pointer or TAB key to move from one frequency to another and enter the desired test level The row of buttons at the bottom of the screen allows the technician to do the following e Adjust adjust the audiometer in real time if a precision output level adjustment is available e Measure All measure all frequencies sequentially with software prompts e Measure Selected measure only the currently highlighted frequency with software prompts e Next Test move to the next measurement in the Measurements list in the upper left window OK end the current test e Cancel cancel the current test 6 12 Hearing Level Test AUDit Manual AUDit Manual Press Measure All to perform a hearing level test using the speakers Since frequency modulation is required for this test you will also be prompted to select a FM test signal A Set WEEE 70 dBHL Left at 125 Hz FIGURE 6 12 Level and Frequency Set Dialog Set the appropriate level and frequency then press OK Each frequency will be tested until all have been measured consecutively This test can be performed in less than one minute by pressing the audiometer frequency increment button and then immediately pressing the Enter key OK on the computer Hearing Level Test with Speakers 6 13 6 14 Hearing Level Test AUDit Manual Frequency Test
42. PANL Ears Not Covered MPANL C Show ANSI 125 30 0 24 0 Show OSHA 250 0 20 0 16 0 Show Both 500 3 16 0 800 4 19 0 1000 3 21 0 1600 2 25 0 2000 1 23 0 3150 33 0 4000 32 0 6300 32 0 8000 32 0 FIGURE 4 9 Ambient Level 125 8kHz Results Window AUDit Manual Performing a Booth Test 4 9 NOTE The limits used in these tabs are from Tables III and B2 of the Ameri can National Standard on Maximum Per missible Ambient Noise Levels for Audiometric The OSHA limits are from OSHA 1910 95 Appendix D Saving a Booth Test Once the measurement is completed these three tabs show Booth Test results Figure 4 11 Failed frequencies are indi cated with a red mark In this case the failed 125 Hz third octave measured SPL was 26 9 dB SPL whereas the stan dard allows at most 30 0 for covered and 24 0 for not cov ered ears The exceeded limit values are displayed between parentheses Once the test is complete you may save it by clicking OK at the bottom of the Booth Ambient Levels Measurement screen which will display the dialog box shown in Figure 4 12 FIGURE 4 10 Ambient Level Test Save Window 4 10 Booth Test or Ambient Noise Level Test AUDit Manual Suspecting Instrument Noise File Test Yiew Report SLM Help AUDit Manual G s Should the readings of the ambient test be questionable you may want to check the measurement system noise There are a few ways to do this One simple al
43. Report SLM Help Dja shal rans B E 2 Measurements Frequency Linearity Distortion Pulse Cross Talk Freg Modulation Narrow Band Level Broad Band Noise Speech Transducers Bone Vibrator Speakers Insert Earphone Circumaural Earphone Pee Hearing Level High Freq Input Levels Set Levels to this value 80 Set All Set to Defaults 500 1500 f5 4000 630 1600 0 w 2000 70 2500 30 8 3000 70 3150 70 fo fo fo fo fo S a TDH 39 Earphones Left 2 Right 1 4EC100 Coupler Mic 118894 Adjust Measure All Measure Selected Next Test Save Ok Cancel AUDit Manual 01 15 2013 11 33AM FIGURE 6 2 Hearing Level Screen The Hearing Level screen is typical of the measurement screens On the left below the measurement table you will find the list of transducers for which the audiometer hearing level may be tested The large box at the right has multiple tabs and varies according to the transducer being tested For example all earphones types have four tabs Low and High Freq Input levels Left and Right On the other hand the bone vibrator has only two tabs Input levels and Bone Vibrator Levels In this section the supra aural earphone transducers will be calibrated The procedure is the same for insert and circumaural earphones Hearing Level Test with Earphone Transducers 6 3 To perform a test of the supra aural earphones highlight the Supra aural Earphone transducer list it
44. SWW 824 utility software CD WS001 3 1 2 inch foam windscreen AM814 06 Neg Pos AA term Spring Assy for individual AA battery cell use Audiometric test internal 824 firmware option BNC to 1 2 inch preamp thread adaptor with equivalent 47 pF capacitance for direct input to 824 1 2 inch preamp to 1 inch microphone thread adaptor Audiometer earphone adaptor for electrical input to 824 6cc coupler NBS 9 A coupler with base coupler retaining ring microphone cap mass and handle weight and pillow 1 2 inch MIC TO 1 inch CAL adaptor Precision microphone calibrator with 1 inch opening 1250 1 CAL250 operation manual Weather tight hard carrying case USB to serial adaptor 10 foot microphone extension cable Audiometer calibration software including IAUDit 01 software operator manual and media Unpacking and Inspection 1 3 SYS009 with AMC493B 1 inch precision pressure response microphone and case Precision integrating sound level meter including PRM902 1 2 inch preamplifier with 7 pin LEMO connector PSA027 90 264 Volt to 12 V Power supply BAT010 nickel metal hydride AA rechargeable battery pack CBLOO6 serial communications cable with 9 pin D connector CBL042 stereo phone plug to dual BNC output cable 1824 01 operator manual 1824 02 training manual 1824 03 firmware upgrade instruction sheet SWW 824 F utility software CD WS001 3 1 2 inch foam windscreen AM814 06 Neg Pos AA term Spring Assy for individual AA bat
45. Step 6 Replace the grid cap with the protective coupler cap MAE100 3 being careful not to impact the delicate diaphragm FIGURE 5 12 FIGURE 5 12 Installing Protective Ring on 2575 Microphone AEC100 Final Assembly for Testing Supra Aural Earphones The following steps are suggested for audiometer calibration with the AEC100 Step 1 Assemble the coupler as described in the AEC100 Coupler Assembly and Calibration on page 5 4 The coupler base should rest on the isolation pad and ambient noise and vibration should be mini mized Step 2 Perform a calibration of the system as described in AEC100 Coupler Assembly and Calibration on page 5 4 and replace the microphone grid cap with the protective coupler cap MAE100 3 being careful not to impact the delicate diaphragm 5 10 Audiometer Test System Assembly AUDit Manual FIGURE 5 13 Coupler being installed on AEC100 Step 3 Center the test earphone on the coupler Lower the black retainer ring over the earphone holding the earphone cable in line with the notch FIGURE 5 14 FIGURE 5 14 Retainer Ring being installed over headphone AUDit Manual AEC100 Coupler Assembly and Calibration 5 11 Step 4 Lower the mass by its handle to the top of the ear phone FIGURE 5 15 FIGURE 5 15 Mass being installed on AEC100 The coupler and earphone are now ready for measurement AEC201 Ear Simulator and Assembly and Calibration 5 12 For this you will need EXA0
46. Type 1 adapter such as the Sennheiser HDA200 install the Type adapter on the coupler with the AUDit Manual AEC201 Ear Simulator and Assembly and Calibration 5 19 cylindrical rim facing down Place the black coni cal ring on the top of the coupler and plate with its flat base on the bottom FIGURE 5 26 FIGURE 5 26 AEC201 with Type 1 Adapter installed Step 5 For earphones designed to be calibrated with a Type 2 adapter such as the Koss HV 1A use the Type 2 adapter which has crenellated distance clamps around its circumference Do not use the black conical ring FIGURE 5 27 FIGURE 5 27 Type 2 adapter installed on AEC201 Step 6 Center the test earphone on the coupler or place it as recommended if the cushion is asymmetrical 5 20 Audiometer Test System Assembly AUDit Manual Step 7 ANSI S3 6 2010 requires a static force of 9 to 10 N on the earphone during calibration Use the large weight bag FIGURE 5 28 FIGURE 5 28 Sennheiser earphone and weight bag being installed on AEC201 The coupler and earphone are now ready for measurement AMC493B Assembly for Testing Bone Vibrators Bone vibrators are used to test sound conduction through the head Their use is limited to a restricted frequency range The LD AMC493B artificial mastoid uses an innovative AUDit Manual AMC493B Assembly for Testing Bone Vibrators 5 21 Part Number Description design to allow bone vibrator calibration using an AEC100 or AEC201
47. View Report SLM Help Audiometer Test Audiometer Test Notes Booth Test Instrumentation Preferences Stored Measurements Begin or continue audiometer test FIGURE 3 1 Test Menu This will display the Enter Test Location screen FIGURE 3 2 It is the first of a series of entry screens listed in a column on the left side of the screen 3 1 Test Location 3 2 TEAR File Test View Report SLM Help Dae tal Setup Items Equipment Microphones Audiometer Earphones Bone Vibrator Speakers Enter Test Location Location Customer Name JOHN WILKES Location ROOM B12 fi CLINIC CIRCLE ANYTOWN PE 09876 Ok Cancel CAP num FIGURE 3 2 Test Location Dialog Box This is where customer information is entered Test Location FIGURE 3 2 contains the following fields e Customer Name the customer or company name e Location the location of the audiometer telephone number or other information Audiometer Test Setup AUDit Manual Equipment NOTE When the desired instrumenta tion is selected for use with an audiome ter measurement a copy of the selected instrumentation is stored with the mea surement If changes are made to the instrumentation those changes will not be reflected in the copy that is stored with the measurement The equipment used to test the audiometer is selected here from the instrumentation which was entered earlier Equipment that has been previo
48. aching AEC201 Step 7 Connect the instrument cable to the preamplifier The coupler is now ready for level calibration Level calibration is performed with the Larson Davis Model CAL250 precision calibrator It offers a level of 114 dB with an accuracy of 0 2 dB at 251 2 Hz You will have to insert the provided 1 to 1 2 adaptor in the top of the calibrator To calibrate the measurement system and artificial ear follow the procedure below Step 1 Assemble the coupler as described in AEC201 Ear Simulator and Assembly and Calibration on page 5 12 The coupler base should rest on the isolation pad and ambient noise and vibration should be minimized AEC201 Ear Simulator and Assembly and Calibration 5 15 Do not remove the microphone grid Step 2 Place the calibrator opening on the microphone cap and seat it fully FIGURE 5 18 FIGURE 5 19 Installing the CAL250 on AEC201 Step 3 Activate the calibrator as prompted by the soft ware and verify the stability of the indication on the measurement system FIGURE 5 19 Do not hold the calibrator during calibration Its tone will last about one minute depending on the battery and will turn off automatically FIGURE 5 20 CAL250 being activated on AEC201 5 16 Audiometer Test System Assembly AUDit Manual Step 4 AUDit requires a calibration in each of two mea surement ranges The calibrator tone may have to be reactivated for the second calibration as prompted by the software
49. an incompatibility is detected 2 14 Preferences AUDit Manual AUDit Manual Checking the Show warning when there is no RETSPL defined for a given frequency option will cause a warning message to appear before running a test without RETSPL defined for the frequency to be tested as shown in Figure 2 14 Checking the Display frequencies when there is no RETSPL will allow the frequencies in the Hearing Level tests to be displayed without RETSPL being associated with them When RETSPL is not defined for the frequencies to be tested the message shown in Figure 2 14 appears RETSPL not defined for 6000 19000 Hz Test results at these frequencies will be incorrect To correct this do one of the following 1 Enter a valid RETSPL for the above frequencies 2 Unselect the frequencies from the test configuration FIGURE 2 14 Frequencies without RETSPL Click Yes to display all frequencies including those with our without RETSPL Click No to close the dialog box to display only those frequencies with RETSPL Click Cancel to uncheck the option to show this warning message until it is re checked on the Preferences dialog box Checking the Display Ears Not Covered column for Booth Tests option will display columns in the 125 Hz to 8 kHz 250 Hz to 8 kHz and 500 Hz to 8 kHz booth tests and all of the reports Preferences 2 15 Click RS232 Port to access the screen for RS232 communications port options Here you may s
50. ase should rest on the isolation pad and ambient noise and vibration should be mini mized AUDit Manual AEC100 Coupler Assembly and Calibration 5 7 Step 2 Place the calibrator opening on the microphone and seat it fully FIGURE 5 9 Note Do not remove the microphone grid cap FIGURE 5 9 CAL250 being lowered onto 2575 microphone Step 3 Activate the calibrator as prompted by the soft ware and verify the stability of the indication on the measurement system FIGURE 5 10 Do not 5 8 Audiometer Test System Assembly AUDit Manual hold the calibrator during calibration Its tone will last about one minute depending on the battery and will turn off automatically FIGURE 5 10 Starting Calibration tone with on switch In actual practice for most testing Step 4 AUDit requires a calibration in each of two mea the grid cap does not need to be surement ranges The calibrator tone may have to removed This will help reduce the be reactivated for the second calibration as possibility of accidental damage to prompted by the software the delicate and expensive precision Step 5 j See Note at left before proceeding After the cali microphone diaphragm bration carefully remove the grid cap by holding the microphone body and unscrewing the grid counterclockwise FIGURE 5 11 Store it in the microphone case AUDit Manual AEC100 Coupler Assembly and Calibration 5 9 FIGURE 5 11 Removing grid cap from 2575 Microphone
51. ate of the 824 to an active RS 232 port on the computer FIGURE 5 2 FIGURE 5 2 Connecting CBL006 to 824 Step 2 Connect the male end of the EXA010 extension cable to the nose cone of the 824 by matching the red dots on mating connectors FIGURE 5 3 FIGURE 5 3 EXA010 extension cable approaching System 824 Step 3 After the PRM902 microphone preamplifier has been inserted and treated in the appropriate cou pler see below connect it to the nose cone of the AUDit Manual Connect the PC 824 and PRM902 Preamplifier 5 3 824 with the EXA010 extension cable by match ing the red dots on mating connectors FIGURE 5 FIGURE 5 4 Preamp connecting to extension cable and to AEC100 Step 4 The 824 SLM may now be turned on by parame ters Pressing the key on the 824 Step 5 Press O scroll down with the to Commu nication and press P to edit Serial Comm parameters Set the parameters as desired 9600 Baud serial address 000 and Hdwr flow control are suggested AEC100 Coupler Assembly and Calibration 5 4 For this you will need the following Part Number Description AUDit AUDit software running on a PC CBL0O06 serial cable f Serial cable 8 pin mini DIN to DB 9 824 System824 precision sound level meter SLM EXA010 10 foot extension cable with 7 pin LEMO connectors 2575 1 precision air condenser microphone PRM902 1 2 diameter low noise microphone preamplifier CAL250 Precision SPL calibrator w
52. ations such as American National Standards Institute Specifications for Audiometers S3 6 2004 When configuring the audiometer transducer test the AUDit software suggests or defaults to appropriate setups These test setups are covered in greater detail in subsequent sections Telephonics TDH 39 49 50 Sennheiser HDA200 Koss HV 1A Radio Ear B 71 Speakers Insert Earphone AEC100 NBS 9 A cou pler or AEC201 IEC 60318 Ear Simulator AEC201 IEC 60318 Ear Simulator with MAEC101 06 Type 1 adaptor plate AEC201 IEC 60318 Ear Simulator with MAEC101 07 Type 2 adaptor plate AEC100 NBS 9 A cou pler or AEC201 Ear Simulator and AMC493B Artificial mastoid Use ambient noise level test setup from Chapter 4 AEC202 or AEC203 2 0 cm or Type 2 coupler AEC204 ear simulator Use 4 5 N weight Test up to 8000 Hz Use 9 10N weight Extended frequency tests up to 16000 Hz may be performed Use 9 10N weight Extended frequency tests up to 16000 Hz may be performed Use 9 10N weight Refer to earphone and coupler manufacturer information Table 5 1 Audiometer Transducer Test Configurations Connect the PC 824 and PRM902 Preamplifier WARNING Before continuing ensure that the 824 SLM is turned off The 824 should remain off until the system is fully assem bled Audiometer Test System Assembly AUDit Manual Step 1 Connect the CBL006 RS 232 cable from the SERIAL connector on the butt pl
53. bone vibrator used for bone conduction audiometry Information is entered by clicking Test Instrumentation And selecting Mastoids in the upper left box of the screen Only two types of mastoids are currently supported by AUDit software the Larson Davis Model AMC493 and Bruel amp Kjaer 4930 artificial mastoids Therefore the Manufacturer entry is a pull down menu with those two choices Enter the manufacturer model and serial number of your mastoid and its calibration due date It is not necessary to enter a sensitivity with the Larson Davis artificial mastoid AMC493B information can be imported directly from a csv file using Import Data The Bruel amp Kjaer calibration chart typically has three parts Enter values read from Page 2 Frequency Response at constant dynamic force using the 5 4 N black curve Entering Instrumentation 2 9 File Test view Report SLM Help Dja af atlas lea 2 Instrumentation Select available Mastoid or enter data to add a new instrument Sound Level Meters F Calibrators Mastoid AECT o0 Sensitivity AEC101 Sensitivity A4EC201 Sensitivity Microphones Note To manually enter data for new instrument you must enter or change the serial number before you can add the instrument Manufacturer Larson Davis EF Current Model am C4938 Mastoids 4930 SN 2022839 Serial number 5339 AMC493B SN 5417 Sensitivity p 00 mN year month day Calibration due 2
54. bration system software maintains all tests audiometer and booth in a database which is compatible with database software This section will illustrate the use of the database to retrieve booth and audiometer measurements To recall a stored measurement click on the Test Stored Measurements item on the main menu bar FIGURE 17 11 Beta Demo AUDit File BESA View Report SLM Help 4udiometer Test Audiometer Test Notes Booth Test Instrumentation Preferences Stored Measurements FIGURE 17 11 Test Pull Down Menu Stored Measurements items Stored Measurements Database Functions 17 9 Audiometer Measurements The audiometer measurements available in the current AUDit database can be searched with the dialog box shown in FIGURE 17 12 Audiometric Measurements Booth Test Data Search database by entering a Technician name Audiometer Model Audiometer Serial number and or a date range List all tests in the database by leaving the edit fields blank Technician Model Serial Num From Date To Date Channel Al Update List Technician Date da 3 24 2010 GSI 1761 Mar 28 2010 da 5 12 2010 GSI 1761 May 12 2010 da 6 12 2010 GSI 1716 May 12 2010 da 5 28 2010 GSI 1716 May 28 2010 da 5 30 2010 GSI 1716 May 30 2010 da 5 30 2010 corecte GSI 1716 May 30 2010 da 5 30 2010 corecte GSI 1716 May 30 4096 GSI 1716 May 30 2010 GSI 1716 May 31 2010 16 Jun 02 2010 16 Jun
55. broad band white noise masking measurement using narrow band fast Fourier transform FFT analysis The requirements of ANSI S3 6 2004 are listed in Section 6 3 2 A minimum sound pressure spectrum flatness of within 5 dB of the level at 1000 Hz is required The measurement is performed with an appropriate coupler Broad Band Masking Measurement Screen To perform a broad band noise test from the main audiometer test status screen highlight the Broad Band Noise test with the pointer and click the Go To Measurement button FIGURE 14 1 AUDit Manual Broad Band Noise Masking Test 14 1 Beta Demo AUDit DE Broad Band Masking Most Analog Audiometers can not meet i 470 ANSI S3 6 6 3 2 standard 1000Hz HL Dial Setting Choose 1000 Hz or Overall C Overall Sound Source _SPL 1000H2 Hearing Level Deviation Target SPL X white Noise 79 9 59 9 10 1 87 0 to 93 0 Tape CD A 80 2 60 2 38 87 0to93 0 Tape CD B 80 1 60 1 39 87 0 to 93 0 Transducers Supra aural Earphon Insert Earphone Circumaural Earphone TDH 50 Earphones Left 1 Right 1 AEC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Cancel FIGURE 14 1 Broad Band Masking Measurement Screen All earphones types have two tabs Left and Right In this example the supra aural earphone transducers will be calibrated The procedure is the same for all listed transducers Highlight the Supra aural Earphone transducer list item The Supra au
56. ceeeseeeeeeseseeseesaecsecaeceesseeaeees 2 3 Preferentes irreg irise a cules Sa S NN EEEREN EIRE atek cutee REAS SRE 2 13 Audiometer Test Setup 3 1 Equipment 3635 28 34 ran ees eh A R E le NE R 3 3 Microph neS sssrinin aeea aaee E EERS have Ea e 3 4 AUGIOMETSN ssi e e E EE E E T E EE EE oS Era EEST 3 7 Earphones Screen oen Based ienee r eee Agen Meteosat ete 3 8 Booth Test or Ambient Noise Level Test 4 1 Equipment for Booth Testo eeeesccessecencecseceeeeceeeeceaeeenceeeecaeeeneeeeecsaeeeaeeceeeenes 4 2 Assembling the System ee nr E E EA a EN E 4 3 Connecting the SLM veyed pe ine eaea arees eoe sae EE Sa aSK ines 4 5 System Acoustic Calibration 0 0 eee eececeseeeeeeseeeeesaeceseaeceecesceseeeeesseseeseneeaes 4 6 Performing a Booth Test sssini cseceeceeesseesecesceeceeseeeseeseaseseesaecaeeeaecneseeeeeeees 4 8 Saving a Booth Test visccccaccsssccssssesisees sag taschisbtiiaee tsp isecsi eeveon hi csieeaskeuoe se 4 10 Suspecting Instrument Noise 0 0 eee cee eeeeeeecseeceecacesaeeseceseeseceseeeeseeeaaesaeeaes 4 11 Audiometer Test System Assembly 5 1 Audiometer Transducer Test Configurations 2 0 0 0 ce eeeecceeseeeeeseeneeeseceeaeeneens 5 2 Connect the PC 824 and PRM902 Preamplifier eee eeesse cee ceeceeeeeeeeeees 5 2 AEC100 Coupler Assembly and Calibration 2 0 0 0 ee ceececeeeeeeereessececnseeeeeeees 5 4 AEC201 Ear Simulator and Assembly and Calibration 0 eee eeeeeeeeee 5 12 AMC493B Assembly for Testing Bone Vibrators 0
57. cel FIGURE 15 6 Bone Vibrator Test Screen To perform a test of the bone vibrator transducer highlight the Bone Vibrator transducer list item The default output level is present at the upper right hand side The measured SPL value from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed Press Measure All to perform all speech tests on the bone vibrator If you are using a Larson Davis Mastoid you will be prompted to enter temperature and humidity values used within the software for artificial mastoid corrections FIGURE 15 7 15 6 Speech Test with Bone Vibrator AUDit Manual Temperature Humidity Humidity 45 Temperature 22 0 4D Pressure fior 30 in mmHg or kPa FIGURE 15 7 Temperature and Humidity Entry Box Hint degrees C degrees F 32 x 5 9 Speech Test with Speakers Left Right Binaural Incidence Angle p Source Measured SPL Hearing Level Mic Tape CD A Tape CD B Speech Noise Left Speaker 1 1 Right Speaker 1 2 Mic 1316 Measure All Measure Selected Next Test HL Dial Setting z0 Deviation Target SPL 28 83 5t089 5 FIGURE 15 8 Speaker Test Screen AUDit Manual Speech Test with Speakers 15 7 Sound field audiometric testing using speakers may be performed in a variety of ways In table 9 ANSI S3 6 2004 lists reference equivalent threshold sound pressure levels RETSPL for binaural listening in f
58. columns are also 2 The measured SPL value from the sound level meter is displayed converted to hearing level and the deviation from the target SPL is displayed along with the permissible target SPL range Click Measure All to perform a narrow band level test on the current earphone AUDit then displays the prompt shown in Figure 13 3 for the first frequency AUDit AUDit Manual Narrow Band Level Test with Earphone Transducers 13 3 13 4 FIGURE 13 3 Level and Frequency Set Dialog Box Set the appropriate narrow band level and frequency then press OK Each frequency will be tested consecutively until all have been measured This can be done very quickly by pressing the audiometer frequency increment button and then immediately pressing the Enter OK key on the computer Narrow Band Level i Right Low Freg Input Levels High Freq Input Levels Frequency Measured SPL Hearing Level Deviation Target SPL 125 113 9 100 0 88 1 83 8 83 9 83 0 87 7 88 8 87 4 84 5 85 7 68 4 1 6 118 5 to 126 5 69 5 0 97 5 to 105 5 70 6 i 84 5 to 92 5 70 3 i 80 5 to 88 5 70 4 i 80 5 to 88 5 69 5 D 80 5 to 88 5 70 7 84 0 to 92 0 73 3 82 5 to 90 5 71 9 82 5 to 90 5 66 0 4 85 5 to 93 5 85 0 to 93 0 TDH 50 Earphones Left 1 Right 1 4EC100 Coupler Mic 1316 FIGURE 13 4 Narrow Band Level Test Results Screen Tests that are out of tolerance limits will be indicated by a red X After adjustment any failed frequen
59. coustic Near Field for the advantages of being in the acoustic far field Geometric Far Field The distance from a source of sound is greater than the largest dimension of the sound source In the far field the effect of source geometry is negligible Sound sources often have a variety of specific sources within them A 3 Free Field Frequency Hz rad sec Frequency Band Pass Filter A 4 such as exhaust and intake noise When in the far field the sources have all merged into one so that measurements made even further away will be no different See the defini tion of Geometric Near Field for the advantages of being in the geometric far field A sound field that is free of reflections This does not mean that the sound is all coming from one direction as is often assumed since the source of sound may be spatially exten sive See the definitions of near and far fields for more detail This definition is often used in conjunction with reverberant field The rate at which an oscillating signal completes a complete cycle by returning to the original value It can be expressed in cycles per second and the value has the unit symbol Hz Hertz added and the letter f is used for a universal descrip tor It can also be expressed in radians per second which has no symbol and the greek letter is used for a universal descriptor The two expressions are related through the expression 2 11 f The part of certain sound level met
60. crophone used for open air measurements such as the ambient noise level measurement of the Booth Test or speakers tests Audiometer a GSI 1761 0919 AUDit DER File Test View Report SLM Help Setup Items Audiometer Description Audiometers Low Frequencies High Frequencies Audiometer Manufacturer Welch Allyn Bone Vibrator Speakers Model GSI 1761 Audiometer Type 1 Serial Number 0919 Inventory Number 002139 year month da Number of Channels 16 2 v Date last calibrated 2011 Sep v Channel to test Calibration due date 2012 Sep f4 1 amp Carrier frequency modulation rate of 4 5 Hz with FM tone Deviationat 85 Z See Manufacturer s specification sheet for modulation rate and Tone Deviation Cancel FIGURE 3 5 Audiometer Description Screen 3 6 Audiometer Test Setup AUDit Manual AUDit Manual The Audiometer Description screen contains information on the audiometer or signal generator under test while its transducers are defined in the remaining screens of the setup items The Audiometer Description screen is composed of three different tabs to describe the audiometer and the frequencies at which it is tested Audiometer 3 7 Audiometers Tab NOTE American National Standard S3 6 2004 Specifications for Audiome ters specifies the designation of audiom eters e g Type 3 Type 4 satisfying the standard The minimum required facili ties for each designation are listed in
61. crophones are not direc tional so they measure whatever is there regardless of source Rules 1 When making hand held measurements keep your body at right angles to the direction of the sound you are inter ested in and hold the meter as far from your body as possi ble Use a tripod whenever possible 2 Measure the influence of other sources by measuring the background sound level without the source of interest You may have to correct for the background There are two types of near fields the acoustic near field and the geometric near field Acoustic Near Field The distance from a source of sound is less than an acoustic wavelength In the near field the effect of the type of sound source is significant Since the wave length varies with frequency See the definition of Wave length the distance will vary with frequency The most common example of a near field is driving an automobile with an open window As you move your ear to the plane of the window the sound pressure level builds up rapidly wind noise since most of the pressure changes are to move the air and very little of it compresses the air to create sound Per sons not far way can hardly hear what you hear The acous tic near field is characterized by pressures that do not create sound that can be measured in the far field Therefore mea surements made here are not useful in predicting the sound levels far way or the sound power of the source Geometric Near F
62. cy may be retested with the Measure Selected button Narrow Band Level Test with Earphone Transducers AUDit Manual Narrow Band Level Test with Speakers Narrow Band Level Right Binaural Low Freq Input Levels High Freq Input Levels Incidence angle 0 Frequency 125 250 500 750 Measured SPL C 45 C 90 Hearing Level Deviation Target SPL Left Speaker 1 1 Right Speaker 1 2 Mic 3361 Measure All Measure Selected Next Test Save Cancel AUDit Manual FIGURE 13 5 Narrow Band Test With Speakers Screen Sound field audiometric testing using speakers may be performed in a variety of ways Table 9 ANSI S3 6 2004 lists reference equivalent threshold sound pressure levels RETSPL for binaural listening in free field at 0 degree incidence as well as monaural listening in sound field for 0 45 and 90 degree incidence These RETSPLs are used in AUDit to translate the measured sound pressure levels to hearing level Note that the prescriptions in Section 9 5 1 of the standard for sound field characteristics should be followed These include the requirement that the ambient noise in the sound field shall not exceed that specified in ANSI S3 1 1991 The ambient noise Booth test in AUDit is helpful in making this determination Narrow Band Level Test with Speakers 13 5 To perform a test using speakers highlight the Speakers transducer list item The Narrow Band Level screen Figure 13 5 for the spea
63. d Most often it converts the changing pressure associ ated with sound into an electrical voltage that duplicates the changes It can be composed of one of the following types Capacitor Condenser A microphone that uses the motion of a thin diaphragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal For high sensitivity this device has a voltage applied across the diaphragm from an internal source Electret A microphone that uses the motion of a thin dia phragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal The voltage across the diaphragm is caused by the charge embedded in the electret material so no internal source is needed Microphone Uses The frequency response of micro phones can be adjusted to be used in specific applications Among those used are Frontal incidence Free Field The microphone has been adjusted to have an essentially flat frequency response when in a space relatively free of reflections and when pointed at the source of the sound Random incidence The microphone has been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions Pressure The microphone has not been adjusted to have an essentially flat frequency response for sound waves imping ing on the microphone from all directions What a microphone measures A microphone detects
64. dd a new instrument Sound Level Meters Calibrators Microphone Low Freq Response High Freq Response Grid Corrections Enter response values from chart included with microphone 31 5 500 0 03 2000 0 06 s000 j 1 6 630 0 04 2500 0 03 3000 0 03 3150 0 02 aooo 012 s000 01 1500 0 07 6000 0 13 6300 foai Cancel 750 1 0 05 Current Microphones soo 0 05 2559 SN 3322 i 1000 0 06 1250 0 06 Import Data 1600 0 07 Update Delete For Help press F1 FIGURE 2 7 Microphone Frequency Response Information Dialog Box High frequency and grid cap corrections may not be necessary if you are not performing the calibration of extended frequency audiometers AUDit Manual Entering Instrumentation 2 7 2 8 Larson Davis 2575 1316 0 43 0 36 0 29 0 23 0 18 0 14 0 1 0 07 0 05 0 03 0 01 0 0 01 0 02 0 03 0 04 0 05 0 06 0 06 0 06 0 06 0 06 0 07 0 07 0 07 0 07 0 07 0 07 0 06 0 06 0 06 0 05 0 04 0 03 0 0 40 96 4 13 2009 FIGURE 2 8 Example of Imported CSV File Entering Instrumentation AUDit Manual AMC493 Artificial Mastoid The sensitivity of a B amp K mastoid is found on its calibration chart under the heading Force Sensitivity including cable and is in units of mV N Field tests show the sensitivity offset for the AMC493 to be approximately 12 5 dB AUDit Manual The artificial mastoid is used to calibrate the
65. dulation Measurement Screen File Test View Report SLM Help Measurements Hearing Level Frequency Linearity Distortion Pulse Cross Talk Narrow Band Level Broad Band Noise Speech Transducers Supra aural Earphone Insert Earphone Circumaural Earphone AUDit Manual Frequency Modulation ANSI Limits 3 121 3to 128 7 242 5to 257 5 485 0to 515 0 727 5to 772 5 970 0to 1030 0 1455 0to 1545 0 1940 0 to 2060 0 2910 0to 3090 0 3880 0 to 4120 0 5820 0 to 6180 0 7760 0 to 8240 0 TDH 50 Earphones Left C 28280 Right C 28281 AEC100 Coupler Mic 1316 Rate 6 0 Hz Dev 9 0 Measure Selected Next Test Save Ok Cancel 09 29 AM Measure All 01 08 2013 FIGURE 12 1 Frequency Modulation Test Screen Frequency Modulation Test 12 1 On this screen all values come directly from the meters To perform a frequency modulation test from the main audiometer test status screen highlight the Freq Modulation test with the pointer and press the Go To Measurement button In this example the supra aural earphone transducers will be calibrated Highlight the Supra aural Earphone transducer list item The Frequency Modulation tabs will appear on the right part of the screen You may select which earphone to test by pressing on the Left or Right tab Press Measure All to perform a frequency modulation test on the left earphone AUDit then displays the prompt shown in FIGURE 12 2 to measure the f
66. e performed in a variety of ways Table 9 of ANSI S3 6 2004 lists reference equivalent threshold sound pressure levels RETSPL for binaural listening in free field at O degree incidence as well as monaural listening for 0 45 and 90 degree incidence These RETSPLs are used in AUDit to translate the measured sound pressure levels to hearing levels Note that the prescriptions in section 9 5 1 of the standard for sound field characteristics should be followed These include the requirement that the ambient noise in the sound field shall not exceed that specified in ANSI S3 1 1991 The ambient noise Booth test in AUDit is helpful in making this determination To perform a test using speakers highlight the Speakers transducer list item The Hearing Level screen for the Hearing Level Test with Speakers 6 11 speakers transducers has five tabs as shown previously in F FIGURE 6 lt n 1 gt e Left e Right e Low Freq Input Levels e High Freq Input Levels e Binaural If the Left tab is selected as shown an incidence angle of 0 45 or 90 degrees must be chosen so that the appropriate RETSPL correction is applied Note the headers at the top of the table Measured SPL value from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed The Right tab operates in exactly the same manner The Binaural tab has only one incidence angle selection zero degrees For Low Freq Input Level or High
67. earphones typically rest against the head with little or no contact with the pinna external ear Their speaker or driver is coupled to the ear with a relatively large volume of air under the ear cap 5 18 Audiometer Test System Assembly AUDit Manual RETSPLs for two circumaural earphones are listed in Annex C of ANSI S3 6 2010 These two types of cirumaural earphones are available in AUDit the Sennheiser HDA200 and Koss HV 1A Environmental conditions It is stated in various standards that the extended high frequency calibration of circumaural earphones be performed only when the following environmental conditions are met Condition Range in ANSI S3 6 2010 Range in IEC 60318 1 2009 Annex C Clause 6 Calibration 98 to 104 kPa 98 325 to 104 325 kPa 18 to 26 degrees C 20 to 26 degrees C Relative Humidity 30 to 80 RH 30 to 70 RH AEC201 Configuration The following steps are suggested for circumaural earphone audiometer calibration with the AEC201 Step 1 Assemble the coupler as described in theAEC201 Ear Simulator and Assembly and Calibration on page 5 12 The coupler base should rest on the iso lation pad and ambient noise and vibration should be minimized Step 2 Perform a calibration of the system as described in AEC201 Acoustic Calibration on page 5 15 Step 3 Screw the coupler over the base FIGURE 5 25 FIGURE 5 25 Coupler being installed on AEC201 Step 4 For earphones designed to be calibrated with a
68. elect port number COM1 to COM8 and RS232 baud rate 300 to 115kBaud from pull down menus GSI 1761 12345 AUDit DER File Test View Report SLM Help System setup items Communications Port Options Organization AS232 Setup Sound Level Meter RS 232 Port COM1 lt Communications Pc COM1 lt Communications Port gt COMS lt ATEN USB to Serial Br COM lt Silicon Labs CP210 U RS 232 Port Baud Rate JbUU v Cancel FIGURE 2 15 RS 232 Communications Dialog Box You have now completed the initial configuration of the AUDit software In the next chapter the system will be assembled and calibrated to perform an audiometric booth ambient level test 2 16 Preferences AUDit Manual Audiometer Test Setup For every audiometer test the AUDit software allows you to fully define the measurement as well as the components of the equipment under test When a measurement is defined all this information is recorded in the database Therefore an audiometer system only needs to be defined once saving a lot of time in subsequent tests In this chapter you will set up the audiometer test by performing this data entry You will be able to refer to instruments which were entered previously in the Instrumentation screen Audiometers and their many transducer types will also be entered To begin entering test information click the Test Audiometer Test drop down menu item FIGURE 3 1 w GS 1761 12345 AUDit
69. elp year month day TestDate 2010 Aug z 17 Audiometer Grason Stadler GSI 1761 SN 12345 Calibration Technician demo GSI 61 Supra aural Insert Circumaural Earphones Bone vibrator Speakers Earphones Earphones Frequency Linearity Harmonic Distortion Pulse Cross Talk Frequency Modulation Narrow Band Level Broad Band Noise Speech Go To Measurement Go To Equipment Setup Cancel Done CAP NUM FIGURE 6 1 Main Measurement Screen The main measurement screen allows one to enter the test date and technician name The tested audiometer manufacturer model and serial number are displayed as AUDit Manual Hearing Level Test 6 1 The SLM should be calibrated before a measurement is performed entered in the previous setup A table of tests and transducers shows the available tests for the particular audiometer For example the Hearing Level test may be performed with supra aural insert or circumaural earphones as well as with the bone vibrator and speakers Appropriate corrections are applied within each test using microphone coupler and standard adjustments To begin the audiometer calibration process highlight the Hearing Level test with the pointer and press the Go To Measurement button If you are already in a test screen press the same test in the Measurements window at the upper left 6 2 Hearing Level Test AUDit Manual Hearing Level Test with Earphone Transducers File Test View
70. em The four Supra aural Earphone Hearing Level tabs will appear on the right part of the screen Default low and high frequency input levels are typically set to 70 dB HL on each tab Each value may be changed by highlighting it and entering a new value Use the pointer or the TAB key to move to another frequency Once the input levels have been verified one may select which earphone to test by pressing on the Left or Right tab File Test View Report SLM Help Measurements Hearing Level Frequency i ight Low Freq Input Levels High Freq Input Levels Linearity ee Frequency Measured SPL Hearing Level Deviation TargetSPL ulse Cross Talk 125 ws Freq Modulation 250 Narrow Band Level 500 Broad Band Noise 750 Speech 1000 1500 2000 3000 4000 Transducers 6000 8000 Bone Vibrator Speakers Insert Earphone Circumaural Earphone Earphones not selected Coupler not selected Mic not selected Adjust Measure All Measure Selected Next Test Save Ok Cancel CAP NUM FIGURE 6 3 Active Frequencies List The list of the active frequencies selected earlier in the audiometer setup appears in the right window Note the headers at the top of the table The measured SPL value Hearing Level Test AUDit Manual AUDit Manual from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed The row of buttons at the bottom of the screen allows t
71. energy at each frequency In this respect it is similar to white light The rapid oscillatory compressional changes in a medium solid liquid or gas that propagate to distant points It is characterized by changes in density pressure motion and temperature as well as other physical quantities Not all rapid changes in the medium are sound wind noise since they do not propagate The auditory sensation evoked by the oscillatory changes Difference between sound and noise Sound is the physical phenomenon associated with acoustic small pressure waves Use of the word sound provides a neutral description of some acoustic event Generally noise is defined as unwanted sound It can also be defined as sound that causes adverse effects on people such as hearing loss or annoyance It can also be defined as the sound made by other people In every case noise involves the judgment of someone and puts noise in the realm of psychology not physics Rules 1 Use word sound to describe measurements to remove the emotional overtones associated with the word noise Some sound metrics use noise in their name and it is proper to use the name as it is The physical characteristic of sound that can be detected by microphones Not all pressure signals detected by a micro AUDit Manual AUDit Manual phone are sound e g wind noise It is the amplitude of the oscillating sound pressure and is measured in Pascals Pa Newtons per square meter
72. enu bar FIGURE 17 6 Beta Demo AUDit File Test view e uniiey SLM Help Report Certificate Export Test Date __ Compare With FIGURE 17 5 Main Menu Certificate Pull Down Menu item 17 4 Printing a Certificate AUDit Manual Certification Paragraph The certification paragraph is a small unformatted text file which may contain any text you wish to have appear on the certificate The Certification Paragraph dialog box allows the retrieval and modification of a previously saved paragraph as well as the creation of a new paragraph In the example in FIGURE 17 6 the paragraph includes the calibration entity name and text referring to the standard Other comments may be included such as calibration status of the equipment used to calibrate the audiometer FIGURE 17 6 shows the Certificate Paragraph dialog box with options for including borders including the date of signature and displaying the message Includes non standard RETSPL when not using standard RETSPL Certification Paragraph John Loki certifies that this audiometer meets or exceeds the minimum specification ANSI 3 6 2004 Other text relevant to the certification may be provided here Paragraph File Name C Users biverson Documents lengthT est acp IV Include border M Include date of signature MM Display RETSPL Message Edit Save OK Cancel FIGURE 17 6 Certification Paragraph Dialog Box AUDit Manual Printing a Cert
73. er will further describe these functions of the AUDit software Printing Reports The Report menu can only be Both audiometer calibrations and Booth measurements can accessed from the Measurement be printed An audiometer test can be printed in its entirety Summary page or only a subset of the measurements can be output To begin printing a recent or recalled test must be active on the AUDit main screen To recall a previous test follow the procedures outlined later in this chapter Once an AUDit test is active click on Report Report on the main menu FIGURE 17 1 Beta Demo AUDit File Test view Memia SLM Help Export d Compare With Test Date H FIGURE 17 1 Main Menu Report Pull Down Menu If the active measurement is an audiometer measurement the dialog box shown in FIGURE 17 2 will appear AUDit Manual Reports and Data Base Functions 17 1 Hearing level Frequency accuracy Hearing level linearity Harmonic distortion Pulsed tones Cross talk Frequency modulation Narrow band level Broad band white noise Speech hearing level Vv lv v Vv MV Vv Iv Vv Vv Vv IV Display RETSPL Message Select All Clear Al Cancel FIGURE 17 2 Measurement Report Select Box The Display RETSPL Message Click on the desired subset of measurements Cl ick the option does not display the message Select All button to enable printout of all test data or the if only standard RETSPL is being Clear All
74. ers that divides the fre quency spectrum on the sound or vibration into a part that is unchanged and a part that is filtered out It can be composed of one or more of the following types Low Pass A frequency filter that permits signals to pass through that have frequencies below a certain fixed fre quency called a cutoff frequency It is used to discriminate against higher frequencies High Pass A frequency filter that permits signals to pass through that have frequencies above a certain fixed fre quency called a cutoff frequency It is used to discriminate against lower frequencies Bandpass A frequency filter that permits signals to pass through that have frequencies above a certain fixed fre quency called a lower cutoff frequency and below a certain fixed frequency called an upper cutoff frequency The differ ence between the two cutoff frequencies is called the band width It is used to discriminate against both lower and higher frequencies so it passes only a band of frequencies AUDit Manual Frequency Filter Weighted AUDit Manual Octave band A bandpass frequency filter that permits sig nals to pass through that have a bandwidth based on octaves An octave is a doubling of frequency so the upper cutoff fre quency is twice the lower cutoff frequency This filter is often further subdivided in 1 3 and 1 12 octaves 3 and 12 bands per octave for finer frequency resolution Instruments with these filters have a s
75. esigned for simplicity portability and durability System weight volume and component count have been carefully managed Measurements for this system are made using the Larson Davis Model 824 precision sound level meter which enables the user to perform complete Audiometer Calibrations per the requirements of ANSI 3 6 2004 and IEC 60645 2001 as well as testing Maximum Permissible Ambient Noise Levels for Audiometric Test Rooms per ANSI S3 1 1999 R2008 This system offers the following features e A whole range of transducers their corrections and limits have been implemented including circumaural supra aural insert earphones bone vibrators and speakers e A measurement database search allows quick reference to previously calibrated audiometers to speed up test configuration or compare the current test with historical data e Extended frequencies can be tested using appropriate couplers such as the Larson Davis AEC201 coupler and plates Welcome to AUDit Audiometer Intelligent Testing 1 1 Formatting Conventions This manual uses the following format conventions e In step by step directions the process what you do is shown in the right column and the rationale why you do it with other cautions and comments are shown in the left column e User Input this bold sans serif typeface indicates values or selections entered in the software e Screen prompts this bold italic typeface denotes menu items prompts m
76. essages and other textual information reported by the software Unpacking and Inspection If you have received this manual as part of a complete Larson Davis audiometer calibration system this section will acquaint you with its components Your order has been shipped in protective packaging As most audiometer calibration hardware must be recertified on an annual basis please try to save these packing materials for future use Important If your packaging was Please compare your system with the following table and damaged in transit please contact note any discrepancies before contacting your Larson Davis your shipping provider for instruc representative tions on filing a claim 1 2 Formatting Conventions AUDit Manual SYS008 This system has the same components as the SYSO09 with the exception of the AMC493B artificial mastoid Part Description 824 AUD ADP006 ADP008 ADP010 AEC100 ADP019 CAL250 CCS007 DVX011 EXA010 SWW AUDIT AUDit Manual 1 inch precision pressure response microphone and case Precision integrating sound level meter including PRM902 1 2 inch preamplifier with 7 pin LEMO connector PSA027 90 264 Volt to 12 V Power supply BAT010 nickel metal hydride AA rechargeable battery pack CBLOO6 serial communications cable with 9 pin D connector CBL042 stereo phone plug to dual BNC output cable 1824 01 operator manual 1824 02 training manual 1824 03 firmware upgrade instruction sheet
77. firmware option BNC to 1 2 inch preamp thread adaptor with equivalent 47 pF capacitance for direct input to 824 1 2 inch preamp to 1 inch microphone thread adaptor audiometer earphone adaptor for electrical input to 824 1 2 inch MIC TO 1 inch CAL adaptor IEC 60318 1 2009 Ear Simulator with 377A13 microphone Precision microphone calibrator with 1 inch opening 1250 1 CAL250 operator manual Weather tight hard carrying case USB to serial adaptor 10 foot microphone extension cable Audiometer calibration software including IAUDit 01 software operator manual and media AUDit Manual Unpacking and Inspection SYS011 with AMC493B and AEC201 A Part Description Precision integrating sound level meter including PRM902 1 2 inch preamplifier with 7 pin LEMO connector PSA027 90 264 Volt to 12 V Power supply BAT010 nickel metal hydride AA rechargeable battery pack CBLOO6 serial communications cable with 9 pin D connector CBL042 stereo phone plug to dual BNC output cable 1824 01 operator manual 1824 02 training manual 1824 03 firmware upgrade instruction sheet SWW 824 F utility software CD WS001 3 1 2 inch foam windscreen AM814 06 Neg Pos AA term Spring Assy for individual AA battery cell use Audiometric test internal 824 firmware option BNC to 1 2 inch preamp thread adaptor with equivalent 47 pF capacitance for direct input to 824 1 2 inch preamp to 1 inch microphone thread adaptor audiometer earphone adaptor fo
78. for masking and stimulus purposes The Larson Davis audiometer calibration system performs the narrow band level measurements using real time third octave filter analysis Specifications regarding the masking sound level controls are enumerated in Section 7 of ANSI S3 6 2004 Various requirements include the accuracy of the masking sound level which we test here Maximum permissible deviation from the indicated value is 3 dB below to 5 dB above the indicated level see Section 7 4 2 of the standard Narrow Band Level Test 13 1 Narrow Band Level Test with Earphone Transducers File Test View Report SLM Help Measurements Hearing Level Narrow Band Level Broad Band Noise Speech Transducers Speakers Insert Earphone Circumaural Earphone All earphone transducer types have four tabs in the large test window FIGURE 13 1 at the right Left Right Low and High Freq Input Levels In this section the supra aural earphone transducers will be calibrated The procedure is the same for insert and circumaural earphones Narrow Band Level Left Right Low Freq Input Levels High Frea Input Levels Measured SPL Hearing Level Deviation Target SPL RETSPL HL Low HLHi 121 0 100 4 86 3 819 82 4 82 1 855 83 0 85 0 49 0 85 6 69 5 5 118 5to 126 5 51 5 69 9 97 5to 105 5 30 5 84 5to 92 5 175 80 5to 88 5 13 5 80 5to 88 5 13 5 80 5to 88 5 13 5 84 0to 92 0 17 0 82 5to 90 5 15 5 82 5to 90 5 15 5 85 5t
79. g Box Creating a Database AUDit Manual Entering Instrumentation NOTE When the desired instrumenta tion is selected for use with an audiome ter measurement a copy is stored with the measurement If changes are later made to the instrumentation those changes will not be reflected in the copy that is stored with the measurement AUDit Manual The AUDit audiometer calibration software maintains a list of the instruments used for calibration These are normally certified traceable to NIST National Institute of Standards and Technology measurement standards at specified intervals All this information is entered in the Instrumentation Screen shown in FIGURE 2 4 Click Test Instrumentation to display the Instrumentation screen i 61 1234 AUDit View Report SLM Help Audiometer Test Audiometer Test Notes Booth Test Instrumentation Preferences Stored Measurements FIGURE 2 3 File Instrumentation Menu Entering Instrumentation 2 3 2 4 GSI 1761 0919 AUDit File Test view Report SLM Help Instrumentation Calibrators Microphones Mastoids Current Sound Level Meters 824 SN 2431 Select available Sound Level Meter or enter data to add a new instrument Sound Level Meter Note To enter data for an insrument you must enter or change the serial number before you can add the instrument Manufacturer Larson Davis Model 824 Serial number 2431 year month day
80. g it and pressing the Measure Selected button coupled into the artificial ear Possible The Adjust button is inactive in this screen because sources are HVAC abient noise room frequency measurements are slightly longer and the display noise or vibration Make sure to use the i not effective for adjustment in real time pad and test on a solid surface Verify j that the ambient noise levels are satisfac Follow the same procedure to test the right earphone torily low AUDit Manual Frequency Test with Earphone Transducers 7 5 Frequency Test with Earphone Transducers AUDit Manual CHAPTER Linearity Test Various requirements regarding signal level controls appear in Section 7 of ANSI S3 6 2004 AUDit allows the measurement of linearity from the maximum hearing level down to the noise floor of the measurement system The test frequency maximum dBHL and dial step may be selected by the technician Defaults are 1000 Hz 110 dBHL maximum level and 5 dBHL steps Linearity Measurement Screen GSI 1716 1 AUDit DAR File Test View Report SLM Help Linearity Left Right Test Frequency 1000 0 v Direction bd Max dBHL 110 Dial step 5 DialLlevel dB HL HL Variance MeasuredSPL Measured Step Step Variance TargetStep Narrow Band Level 55 55 7 62 7 j 1 4 0to 6 0 Broad Band Noise 50 50 6 57 6 1 4 0t06 0 Anese 455 525 1 4 0t06 0 40 4 47 4 R 4 0 to 6 0 35 3 42 3 3 R 4 0 to 6 0 30 2 37 2
81. garithmic form of sound pressure It is also expressed by attachment of the word decibel to the number The loga rithm is taken of the ratio of the actual sound pressure to a reference sound pressure which is 20 MicroPascals u Pa There are various descriptors attached to this level depend ing on how the actual sound pressure is processed in the meter Instantaneous The time varying reading on a meter face on in a meter output due to changes in the sound pressure The reading will depend on the time weighting applied The fundamental relationship between the two is logarithmic 20 L 20108 Pens mio C where pg is the reference sound pressure of 20 uPa The square of the sound pressure is a power like quantity that can be expressed in the original form of the level definition Sound Pressure Level can be converted to sound pressure as follows If the sound pressure is 1 Pascal then the sound pressure level is L 2108 20log 50000 20 4 699 94 0dB 20 10 A 12 Calibrators often use a level of 94 dB so they generate a sound pressure of 1 Pascal If the sound pressure level 76 3 dB then the sound pres sure is AUDit Manual Pa 20 10 e10 Sound Speed c Spectrum Frequency Spectrum Time Weighting AUDit Manual 763 20 906108 20e 10 200 0065 0 13 Energy Average Leq The value of a steady sound measured over a fixed time period that has the same s
82. hannels Channel tested Sup ra aural Insert Circumaural Manufacturer Telephentcs Brymer Jonn Model Number DAS A 3h BDAZON Riqht 8 N Left S N Bone Vibrator Manufacturer ad Medel Number 7 Serial Number Manufacturer Model Number Serial Number Instrumentation ppe g ar Modal Sana Number Cal Due Sound Level Matei er av s R2g ait Nll 01 04 Preang raon Davis PRM Open A ms tacn Davis 575 e racn Davis Davis on Davia Davia that FIGURE 17 8 Certificate Paragraph Print Preview Exporting Data Audiometer and booth test data are maintained in a database by AUDit You may wish to export the results of a certain test to another application for further manipulation This is possible with the Export function To export test data ensure a new or recalled test is active then select Report Export on the main menu bar FIGURE 17 9 AUDit Manual Exporting Data 17 7 1 Beta Demo AUDit File Test view MOa SLM Help ela hl Report Certificate i export TestDate Compare With FIGURE 17 9 Export Data Main Menu Pull Down Menu As an example an audiometer test file may be exported to csv format and then formatted with Microsoft Excel to add graphs and tables for greater impact Frequency Linearity Harmonic Distortion Pulse Cross Talk Frequency Modulation Narrow Band Level Broad Band Noise Speech Supra aural earphones Left Ea
83. he technician to e Adjust adjust the audiometer in real time if a precision output level adjustment is available e Measure All measure all frequencies sequentially with software prompts e Measure Selected measure only the currently highlighted frequency with software prompts e Next Test move to the next measurement in the Measurements list in the upper left window Press Measure All to perform a hearing level test on the left earphone AUDit then displays the prompt shown in Figure 6 4 for the first frequency Set 70 dBHL Left at 125 Hz E Cancel FIGURE 6 4 Prompt for First Frequency Setting Set the appropriate level and frequency on the audiometer then press OK Each frequency will be tested until all have been measured This can be done in less than one minute by pressing the audiometer frequency increment button and then immediately pressing the Enter OK key on the computer In the example all frequencies passed except for the last 8000 Hz This is indicated by a large red X next to the frequency Hearing Level Test with Earphone Transducers 6 5 File Test View Report SLM Help olaja afua BE e Measurements Freg Modulation Narrow Band Level Broad Band Noise Speech Transducers Bone Vibrator Speakers Insert Earphone Circumaural Earphone Hearing Level Let Fight Low Freq Input Levels High Freq Input Levels Target SPL 112 0to 118 0 94 0to 100 0
84. he time constant is 35ms for the rise and 1 5 sec onds 1500 ms for the decay The reason for the double con stant is to allow the very short signal to be captured and displayed The oscillatory movement of a mechanical system gener ally taken to be solid It is used as a broad descriptor of oscillations The distance between peaks of a propagating wave with a well defined frequency It is related to the frequency through the following equation SKIS where c is the sound speed and f is the frequency in Hz It has the dimensions of length A number that is related to the wavelength of sound and is used to compare the size of objects relative to the wave length or the time delay in sound propagation It is related to wavelength through the following equation 2r _ 2nf_ 92 k c c where A is the wavelength c is the sound speed f is the fre quency in Hz and is the radian frequency It has the dimensions of inverse length AUDit Manual AUDit Manual
85. ield The distance from a source of sound is less than the largest dimension of the sound source In the near field effect of source geometry is significant Sound sources often have a variety of specific sources within them such as exhaust and intake noise When in the near field the sound of a weaker but close source can be louder than that of a more distant but stronger source Therefore measure ments made here can be used to separate the various sources of sound but are not useful in predicting the sound levels and sound spectrum far from the source A 9 Noise Sound Sound Pressure A 10 Typically it is unwanted sound This word adds the response of humans to the physical phenomenon of sound The descriptor should be used only when negative effects on people are known to occur Unfortunately this word is used also to describe sounds with no tonal content random Ambient The all encompassing sound at a given location caused by all sources of sound It is generally random but need not be Background The all encompassing sound at a given location caused by all sources of sound but excluding the source to be measured It is essentially the sound that interferes with a measurement Pink It is a random sound that maintains constant energy per octave Pink light is similar to pink noise in that it has a higher level at the lower frequencies red end of the spec trum White It is a random sound that contains equal
86. ificate 17 5 Creating or Editing a Certification Paragraph To create a new certification paragraph or edit the current paragraph click on Edit Once you are done editing save the paragraph under the same name by clicking on Save or change the file name or location by clicking on Save As Certification paragraphs can only be stored with the acp extension Press OK to accept and exit to the Certificate Preview Screen Browsing for a Certification Paragraph Certificate Preview Screen To find a previously saved paragraph click on the Browse key Look in AUDit amp e EE paunize 2 10 E test4 acp O DAODisks El test4acp acp ODAOsetupnew E test acp Ej test2 acp Eltest3 acp Filename EMI sample acp Files of type Audiometer Certificate Paragraph acp v Cancel FIGURE 17 7 Search for Certification Dialog Browse Box The selected paragraph will now be displayed in the Edit rectangle After creating recalling or editing a certification paragraph selecting OK will display the certificate preview 17 6 Printing a Certificate AUDit Manual a GSI 1716 5804 AUDit Prey Page IwoPage Zoomln Zoom Dut Close yrs wins ia eek eS of Calibration oh Davia Div West 20 Nort Prove UT Hasi Calibration Date 010 106 Q Technician AZCIIU Tear new Customer 3 Prov Audiomate Manufacturer Model Number CSI 1715 Typa Serial Number 704 Inventory Number of C
87. irst frequency 12 2 Measurement FIGURE 12 2 Set Level and Frequency Dialog Box Set the audiometer to the prompted FM stimulus level and frequency then press OK There may be a delay while the measurement system acquires an average reading FIGURE 12 3 Measuring 1 of 3 Attempting to read stable data from the 824 FIGURE 12 3 Noise or Variation Message Window The presence of noise variations in the readings or other problems may prompt the display shown in FIGURE 12 4 Frequency Modulation Measurement Screen AUDit Manual AUDit Try again A Unable to get a good reading probably due to too much external noise FIGURE 12 4 Unable to get Reading Message Window It may be useful to observe the sound level meter display and change output level as needed If the software is unable to retrieve an acceptable measurement the frequency will be skipped Each frequency is tested consecutively in the same manner Frequency Modulation Dial Freg Carrier Freq ANSI Limits i Max Rep rate Deviation 125 125 5 121 3 to 128 7 131 3 4 46 8 6 250 251 0 242 5 to 257 5 262 6 4 47 8 7 500 502 3 485 0 to 515 0 525 0 4 47 8 7 750 755 5 727 5 to 772 5 789 3 4 46 8 8 1000 1004 4 970 0 to 1030 0 1049 3 4 46 8 8 1500 1507 6 1455 0 to 1545 0 1570 0 4 80 8 1 2000 2005 1 1940 0 to 2060 0 2092 9 4 31 8 1 3000 3012 1 2910 0 to 3090 0 3141 3 4 31 8 1 4000 4003 8 3880 0 to 4120 0 4181 5 4 31 8 2 6000 6040 6 5820 0 t
88. ith 114 dB SPL output at 250 Hz The following are AEC100 components Audiometer Test System Assembly AUDit Manual AEC100 Initial Assembly AUDit Manual WARNING Before continuing ensure that the 824 SLM is turned off The 824 should remain off until the system is fully assem bled The AEC100 artificial ear is an elegant compact precision coupler built to provide a lifetime of dependable use with reasonable care Read the following instructions to unpack inspect and assemble the coupler for the first time Step 1 Place the cushioned vibration isolation pad on a table or other such stable surface near the audiom eter system Step 2 Visually inspect the coupler MAE100 1 for gouges scratches and dents which may affect the measurement especially around the lip which will be in contact with the test earphone Verify that the small metallic wire in the capillary leak hole is present with no other obstructions FIGURE 5 5 FIGURE 5 5 AEC100 with coupler leak hole AEC100 Coupler Assembly and Calibration 5 5 When removing the preamplifier unscrew it by holding on its body not the connector sleeve Step 3 If installed remove the coupler cap MAE100 3 from the artificial ear base SP MAE100 40 by gently unscrewing it counterclockwise FIGURE 5 6 FIGURE 5 6 Protective ring being removed from Step 4 Step 5 AEC100 Inspect a spring loaded contact at the center of the base visually It sho
89. kers transducers has five tabs Low and High Freq Input Levels Left Right and Binaural For the right two tabs the speaker test levels can be specified for audiometric frequencies from 125 to 20000 Hertz The remaining tabs select the speaker s to be tested left right or both binaural In this example the Left tab is selected The incidence angle of 0 45 or 90 degrees must be selected so that the appropriate RETSPL correction is applied The measured SPL value from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed The Right tab operates in the same manner The Binaural tab has only one incidence angle selection zero degrees Click the Measure All button to perform a narrow band NB level test using the speakers Since narrow band modulation is required for this test you will also be prompted to select a NB test signal FIGURE 13 6 Set NB 70 dBHL Left at 125 Hz Cancel FIGURE 13 6 Set Level and Frequency Dialog Box Set the appropriate level and frequency then press OK Each frequency will be tested consecutively until all have been measured This test can also be performed rapidly by pressing the audiometer frequency increment button and then immediately pressing the Enter OK key on the computer Narrow Band Level Test with Speakers AUDit Manual CHAPTER Broad Band Noise Masking Test The Larson Davis audiometer calibration system performs accurate
90. m2 Jan 7 po Import Data Add Update Delete Cancel FIGURE 2 9 Mastoids Information Dialog Box 2 10 Entering Instrumentation AUDit Manual Sample Calibration Report Artificial Mastoid Test Report Sensitivity when used on an AEC201 Model AMC493B Serial Number 5021 AEC201 Serial Number 0102 Tested without Black Conical Ring Sensitivity dB 100 1K 10K Frequency Hz Mastoid Sensitivity reference 20 uPa uN Frequency Sensitivity Uncertainty Frequency Sensitivity Uncertainty Hz dB dB Hz dB dB 250 8 5 0 5 1600 9 4 0 6 315 7 0 0 6 2000 7 9 0 8 400 6 1 0 5 2500 6 1 0 6 500 6 0 0 5 3000 6 2 0 6 630 7 3 0 6 3150 6 9 0 7 750 8 4 0 5 4000 10 4 0 6 800 8 6 0 5 5000 11 8 0 8 1000 9 5 0 6 6000 12 9 0 6 1250 9 9 0 6 6300 13 7 0 5 1500 9 8 0 6 8000 20 1 0 6 Temperature C 23 1 Relative Humdity 49 5 Static Pressure kPa 85 4 2 0 data corrected to 101 3 3 0 Uncertainty at 95 confidence level k 2 Tested by Scott Montgomery on 2 UN2011 Test performed at Larson Davis a division of PCB Piezotronics Inc 1681 West 820 North Provo Utah 84601 Tel 716 684 0001 www LarsonDavis com The results documented in this report relate only to the item s tested This report may not be reproduced except in full without the written approval of the issuer Page 1 of 2 FIGURE 2 10 Sample Artificial Mastoid Response chart AUDit Manual Entering Instrumentati
91. midity Entry Screen Enter the humidity value as well as the temperature in degrees centigrade as indicated on the meter inside the AMC493B storage case AUDit then displays the prompt shown in Figure 6 9 for the first frequency AUDit Manual Hearing Level Test with Bone Vibrator 6 9 FIGURE 6 10 Hearing Level Set Screen Set the appropriate level and frequency then press OK Each frequency will be tested until all have been measured consecutively This can be done in less than one minute by pressing the audiometer frequency increment button and then immediately pressing the Enter OK key on the computer Hearing Level Test AUDit Manual Hearing Level Test with Speakers GSI 1761 0919 AUDit File Test View Report SLM Help Measurements Frequency Linearity Distortion Pulse Cross Talk Freq Modulation Narrow Band Level Broad Band Noise Speech Transducers Supra aural Earphone Bone Vibrator Insert Earphone Circumaural Earphone TER Hearing Level ight Low Freq Input Levels High Freq Input Levels Binaural Incidence angle O C 45 C 90 Frequency 125 250 500 750 1000 1500 2000 3000 4000 6000 8000 Measured SPL Hearing Level Deviation Target SPL Speakers not selected Mic 1316 Adjust Measure All Measure Selected Next Test Save Cancel FIGURE 6 11 Hearing Level Test with Speakers Screen AUDit Manual Sound field audiometric testing using speakers may b
92. n the capillary leak hole is present with no other obstructions FIGURE 5 16 Coupler Spring Loaded contact Leak Hole FIGURE 5 16 AEC201 with coupler leak hole AUDit Manual AEC201 Ear Simulator and Assembly and Calibration 5 13 Step 3 If installed remove the coupler from the artificial ear base by gently unscrewing it counterclock wise Step 4 Inspect the spring loaded contact at the center of the base visually It should extend approximately 5 mm above the threaded ridge The insulator around it should be free of dust and other particles Please do not handle the contact and protect it by keeping the coupler on whenever a microphone is not installed Step 5 Install the 1 2 microphone PCB model 377A13 on the center of the artificial ear base The micro phone should install easily screw it finger tight FIGURE 5 17 FIGURE 5 17 Microphone installed on AEC201 Step 6 Insert the 1 2 microphone preamplifier LD Model PRM902 or equivalent gently in the side port until its threads contact those of the base The preamplifier should install easily screw it finger tight FIGURE 5 18 5 14 Audiometer Test System Assembly AUDit Manual When removing the preamplifier unscrew it by holding on its body not the connector sleeve AEC201 Acoustic Calibration You will need to install the adapter ADPO19 into the CAL250 in order to calibrate 1 2 inch microphones AUDit Manual FIGURE 5 18 Preamp appro
93. nergy Equivalent Sound Level eq Far Field AUDit Manual reference is generally set to be the lowest value of the quan tity The part of a sound level meter that converts the actual fluc tuating sound or vibration signal from the microphone to one that indicates its amplitude It first squares the signal then averages it in accordance with the time weighting character istic and then takes the square root This results in an ampli tude described as rms root mean square The level of a constant sound over a specific time period that has the same sound energy as the actual unsteady sound over the same period T3 rP t dt 2 Pot where p is the sound pressure and the Measurement Dura tion specific time period T T gt T See Sound Exposure Level There are two types of far fields the acoustic far field and the geometric far field Acoustic Far Field The distance from a source of sound is greater than an acoustic wavelength In the far field the effect of the type of sound source is negligible Since the wavelength varies with frequency See the definition of Wavelength the distance will vary with frequency To be in the far field for all frequencies measured the lowest fre quency should be chosen for determining the distance For example if the lowest frequency is 20 Hz the wavelength at normal temperatures is near 56 ft 17 m at 1000 Hz the wavelength is near 1 1 ft 1 3 m See the definition of A
94. nstrumentation and selecting Calibrators in the upper left box of the screen a GSI 1761 0919 AUDit File Test View Report SLM Help tal aujas BJE el Instrumentation Select available Calibrator or enter data to add a new instrument Sound Level Meters Calibrators Calibrator Microphones Mastoids Note To enter data for an insrument Preamps you must enter or change the serial number before you can add the instrument Manufacturer Larson Davis ae Model CAL250 J Calibrators Serial Number 1234 year month day Calibration Due 2012 z 31 Frequency 251 2 Output Level 114 0 Update Delete Cancel FIGURE 2 5 Calibrator Information Dialog Box AUDit Manual Entering Instrumentation 2 5 NOTE The Larson Davis CAL250 cal Enter the serial number of your calibrator its calibration due ibrator provided with your system has a frequency of 251 2 Hertz and a level of 114 0 dB re 20 micropascals Output fre quency and level are used by the AUDit the calibration procedure Entering incorrect values could lead to measure ment errors Microphone date frequency and output level The calibration year must have four digits Once all fields are completed click Add Microphone information is entered by clicking Test Instrumentation and selecting Microphones in the upper left box of the screen a GSI 1761 0919 AUDit File Test view Report SLM Help Instrumentation Select available Microphone or en
95. o 6180 0 6285 8 4 80 8 3 8000 8052 4 7760 0 to 8240 0 8390 9 4 80 8 3 TDH 50 Earphones Left C 28280 Right C 28281 AEC100 Coupler Mic 1316 FIGURE 12 5 Frequency Modulation Results Screen The results of the frequency modulation measurement are listed for each frequency in the tab Figure 12 5 The values are in order AUDit Manual Frequency Modulation Measurement Screen 12 3 12 4 e Dial Freq selected audiometric presentation frequency e Carrier Freq measured carrier frequency of the modu lated signal e ANSI Limits allowed range within 3 of the nominal frequency e Min minimum frequency of the FM signal e Max maximum frequency of the FM signal e Rep Rate rate at which the FM signal is modulated in hertz must be within 4 to 20 Hz and within 10 of the value stated in the audiometer setup screen Deviation It must be within 10 of the value stated in the audiometer setup screen Any value which is out of tolerance is displayed within parentheses Frequencies out of tolerance are indicated by a large red X A failed frequency may be retested after adjustment by highlighting it and pressing the Measure Selected button Follow the same procedure to test the remaining transducers Frequency Modulation Measurement Screen AUDit Manual Narrow Band Level Test The Narrow Band Level Test is very similar to the Hearing Level test covered earlier Narrow band noise is available in certain audiometers
96. o 93 5 18 5 85 0to 93 0 18 0 TDH 50 Earphones Left C 28280 Right C 28281 AEC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Ok Cancel 01 22 2013 08 44 AM NUM FIGURE 13 1 Narrow Band Level Measurement Screen 13 2 To perform a test of the supra aural earphones highlight the Supra aural Earphone transducer list item Default low and high frequency input levels are typically set to 70 dB HL on each tab Narrow Band Level Test with Earphone Transducers AUDit Manual Once the input levels have been verified you may select which earphone to test by pressing on the Left or Right tab Left Right Low Freq Input Levels High Freq Input Levels Frequency Measured SPL Hearing Level Deviation TargetSPL 125 121 5 70 0 0 0 118 5 to 126 5 250 100 6 70 1 0 1 97 5to105 5 500 86 1 68 6 1 4 845t0o925 750 82 4 68 9 1 1 80 5 to 88 5 1000 825 69 0 1 0 80 5t088 5 1500 81 1 67 6 24 80510885 2000 85 4 68 4 1 6 84 0t092 0 3000 83 0 67 5 25 825to905 4000 67 8 22 825to0905 gt lt 5000 83 2 64 7 5 3 85 5 to 93 5 85 0 to 93 0 TOH 50 Earphones Left C 28280 Right C 28281 4EC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Cancel FIGURE 13 2 Active Frequencies List If the Show Applied Correction The list of the active frequencies selected earlier in the option is checked the RETSPL HL audiometer setup appears in the right window FIGURE 13 High and HL Low
97. old This is most likely to occur if very low hearing threshold levels are being measured AUDit allows simultaneous assessment of noise levels for audiometric measurements with ears covered or not covered in the frequency ranges of 125 250 and 500 Hz to 8000 Hz This test and its pass fail limits are based on the recommen dations of American National Standard on Maximum Per missible Ambient Noise Levels for Audiometric Test Rooms ANSI S3 1 1991 R2008 It also allows assessment of ambient levels per OSHA 1915 95 Appendix D In order to consider the worst case conditions for an audio metric test the ambient noise test should be performed with all possible noise sources present If certain sources are operating at certain times but not at others it may be neces sary to schedule the measurement accordingly AUDit Manual 4 1 Assembling the system The Larson Davis System 824 precision sound level meter meets all the requirements of the aforementioned standards and rules for the measurement of ambient noise level in the audiometric test room Its low self noise and internal frac tional octave band measurement capability enable it to accu rately measure octave and third octave levels much below the minimum required levels when using a high sensitivity microphone such as the Larson Davis model 2575 Equipment for Booth Test The equipment listed below is suggested for ambient noise testing using AUDit e PC with serial
98. on 2 11 Preamplifier The Larson Davis System 824 precision sound level meter SLM is supplied with a Model PRM902 preamplifier To enter your preamplifier information click Test Instrumentation And select Preamps in the upper left box of the screen GS 1761 0919 AUDit File Test View Report SLM Help lay j d sil B E f 2 Instrumentation Select available Preamp or enter data to add a new instrument Sound Level Meters Calibrators Microphones Mastoids Preamp Note To enter data for an instrument you must enter or change the serial number before you can add the instrument Manufacturer Larson D avis Current Microphone Preamps Model PRM302 Serial number 11234 year month day Calibration due 2012 Oct v EN Delete Cancel FIGURE 2 11 Preamplifier Information Dialog Box Enter the serial number etched on the barrel of your preamplifier and its calibration due date which is typically the same as that of the 824 Once all fields are completed click Add A new Preamp entry will appear in the lower left box 2 12 Entering Instrumentation AUDit Manual Preferences This configuration item allows the entry of the calibrating organization and selection of communication parameters for the System 824 SLM a 61 1234 AUDit View Report SLM Help Audiometer Test Audiometer Test Notes Booth Test Instrumentation Preferences Stored Measurements FIGURE 2 12 Test
99. one Vibrator 6 7 File Test View Report SLM Help To perform a test of the bone vibrator transducer highlight the Bone Vibrator transducer list item The Hearing Level screen for the bone vibrator transducer has two tabs Input Levels and Bone Vibrator Levels In the first tab the test bone vibrator levels can be specified or set to default values Use the pointer or TAB key to move from one frequency to another The Bone Vibrator Levels tab displays calibration results ZA eA lil at Measurements Frequency Linearity Hearing Level Bone Vibrator Levels Input Levels Distortion T 5 Matad C Forhead Pulse Cross Talk Freg Modulation Frequency _In Lvl RETFL FL Mast 3 E b Meas __ Target Lvi Narrow Band Level Broad Band Noise Speech Transducers 20 40 40 40 40 40 40 40 40 40 Insert Earphone Circumaural Earphone 67 0 58 0 48 5 425 36 5 10 5 1 76 5 3 0 11 9 i T 3 86 1 3 0 13 5 g 74 9 3 0 14 4 i y t 68 0 3 0 15 3 i k 61 1 3 0 15 3 E I A 55 6 3 0 17 5 g 52 5 3 0 20 6 E y 55 0 3 0 21 6 k 5 58 3 5 0 23 7 j I x 54 7 5 0 AMC493 Vibrator 3338 AMC493B Mastoid 5417 AEC100 Coupler Mic 1316 7 23 00 P 760 0mmHg H 50 Humidity T emp Adjust Measure All Measure Selected Next Test Save Cancel 01 08 2013 09 13 AM FIGURE 6 8 Bone Vibrator Levels Tab Checking the Sho
100. otion of the diaphragm occurs This occurs at high frequencies and for specific orientations of the microphone Rules 1 Do not use a microphone at frequencies higher than speci fied by the manufacturer to increase the frequency response choose smaller microphones 2 Choose a microphone for free field or random incidence to minimize the influence of orientation A microphone influences the sound being measured The microphone measures very small forces low level sound can run about one billionth of a PSI Every measurement instru ment changes the thing being measured and for very small forces that effect can be significant When sound impinges directly on a microphone the incident wave must be reflected since it cannot pass through the microphone This results in the extra force required to reflect the sound and a microphone output that is higher than would exist if the microphone were not there This is more important at high frequencies and when the microphone is facing the sound source Rules 1 Do not use a microphone at frequencies higher than speci fied by the manufacturer to increase the frequency response choose smaller microphones AUDit Manual Near Field AUDit Manual 2 Choose a microphone for free field or random incidence to minimize the influence of orientation A microphone measures what is there from any direction Most measurements are intended to measure the sound level of a specific source but most mi
101. ound energy as the actual time varying sound over the same period This descriptor is widely used It is a fixed average See Sound Pressure Impulse The value of an impulsive sound The reading will depend on the time weighting applied Unweighted Peak The peak value of a sound with a meter that has flat frequency weighting and a peak detector Weighted Peak The peak value of a sound with a meter that has a frequency weighting other than flat and a peak detec tor The speed at which sound waves propagate It is measured in meters per second It should not be confused with sound or particle velocity which relates to the physical motion of the medium itself c 20 05 degC 273 m s c 49 03 degF 460 ft sec The amplitude of sound or vibration at various frequencies It is given by a set of numbers that describe the amplitude at each frequency or band of frequencies It is often prefixed with a descriptor that identifies it such as sound pressure spectrum It is generally expressed as a spectrum level The response speed of the detector in a sound level meter There are several speeds used Vibration Wavelength 1 Wavenumber k A 14 Slow The time constant is second 1000 ms This is the slowest and is commonly used in environmental noise mea surements Fast The time constant is 1 8 second 125 ms This is a less commonly used weighting but will detect changes in sound level more rapidly Impulse T
102. r connected to a network Communications One available 9 pin serial communication port 9600 baud or greater recommended or DVX011 USB Adapter to DBM9 interface 824 to USB port on PC Place the AUDit CD in your PC and follow the onscreen instructions You can accept the default settings on each screen for proper installation FIGURE 1 1 AUDit Icon on desktop Look for new icon on the PC Desktop Contact PCB Piezotronics Technical Support at 888 258 3222 toll free or 1 716 926 8243 if you encounter any problems with the installation or use of AUDit software Software Installation 1 7 Starting the Software Step 1 On the PC desktop double click the AUDit icon to run the software If this is the first time you have used the AUDit software you will be asked if you wish to create a new database A Database C Program Files PCB Piezotronics AUDit2 auditdb mdb doesn t exist Do you want to create a new database Yes Or open an existing database No use File ChangeDatabase FIGURE 1 2 Create new database Dialog Box Step 2 Selecting Yes will create a database named Auditdb mdb in the default directory To create a database later in another directory select No A Could not Open New database keeping old FIGURE 1 3 Could not open database Dialog Window Step 3 You will be able to enter a database name and directory in the File Change Database menu item Press OK to acknowledge the prompt and displa
103. r BNC to 1 2 microphone thread adapter 47 if with shorting ADP007 or ADP006 Test Configuration AUDit Manual cap Larson Davis recommends making measurements as close as possible to the temperature at which the artificial mastoid was calibrated Step 1 Assemble the measurement system as in the sec tion on Connecting the PC 824 and PRM902 Pre amplifier Step 2 Thread the ADP008 onto the preamplifier and then thread the 2575 microphone on the preampli fier FIGURE 5 34 FIGURE 5 34 ADP008 being installed on PRM902 Step 3 Perform a system SPL calibration using the CAL250 AMC493B Assembly for Testing Bone Vibrators 5 27 Step 4 Remove the ADP008 adaptor and 2575 micro phone and replace them with the appropriate adaptor to connect to the artificial mastoid FIG URE 5 35 FIGURE 5 35 Adapters to connect to B amp K mastoid Step 5 Install the bone vibrator on the B amp K 4930 as described in the B amp K user manual The coupler and vibrator are now ready for measurement 5 28 Audiometer Test System Assembly AUDit Manual CHAPTER Hearing Level Test Once AUDit has been configured with the test instrumentation and audiometer information an actual audiometer calibration may be performed The main measurement screen is accessed from the Audiometer Test Setup screen by pressing the OK button Calibration Main Measurement Screen GSI 1761 12345 AUDit DAR File Test Yiew Report SLM H
104. r electrical input to 824 1 2 inch MIC TO 1 inch CAL adaptor IEC 60318 1 2009 Ear Simulator with 377A13 microphone Artificial mastoid coupler and case IAMC493B 01 AMC493B operator manual MAE100 55 additional weight ring Precision microphone calibrator with 1 inch opening 1250 1 CAL250 operator manual Weather tight hard carrying case USB to serial adaptor 10 foot microphone extension cable Audiometer calibration software including IAUDit 01 software operator manual and media Optional Components e AEC202 2cc Artificial coupler for use with 1 2 inch 1 6 microphone for insert earphone measurement Microphone not included e AEC203 2cc Artificial coupler for 1 inch microphone compliant to ANSI 3 7 Microphone not included e AEC204 Ear simulator with 1 2 inch microphone Unpacking and Inspection AUDit Manual Software Installation Hardware and Software Requirements Installing the Software Getting Help AUDit Manual The following table lists the requirements for the installation and use of the AUDit software for audiometer calibration Operating system Windows XP SP3 32 bit Windows Vista Professional SP1 32 bit Windows 7 32 bit and 64 bit and Windows 8 32 bit and 64 bit AUDit software must be installed using Administrator rights Network AUDit is not designed to work on a distributed network from a network drive However it may be operated from a local installation on a compute
105. ral Earphone tabs will appear on the right part of the screen One may select which earphone to test by pressing on the Left or Right tab In the HL Dial Setting enter the Hearing Level Dial Setting that you will use for the measurement Press Measure All to perform a broad band masking test on the left earphone AUDit then displays the prompt shown in FIGURE 14 2 14 2 Broad Band Masking Measurement Screen AUDit Manual GSI 1761 0919 AUDit File Test View Report SLM Help E OGE d png sibl Measurements Broad Band Masking Hearing Level Frequency Left Right Linearity penil ial Setting 70 Distortion Each frequency from 250 Hz to 5000Hz at 25 Hz interval HL Dial Setting Euse Tak Tested against the 1000 Hz level 5dB Freg Modulation View Data Nartow Bandi evel Sound Source Pass Fail Number of Fail Freq at Max Broad Band Noise x White Noise Fail 4 4575 Tape CD a ae aes Tape CD B 71 2 to 81 2 Transducers Insert Earphone Circumaural Earphone TDH 50 49 Earphones Left 28280 Right 28281 AEC100 Coupler Mic 1316 Measure All i g Next Test Save Ok Cancel 08 16 2011 12 41 PM FIGURE 14 3 Broad Band Noise Results Screen The results of the broad band noise measurement are listed in the tabs for each earphone FIGURE 14 3 Tests which are out of tolerance limits will be indicated by a large red X AUDit Manual Broad Band Masking Measurement Screen 14 3 A failed
106. reading AUDit should then display the prompt in FIGURE 11 3 Left Earphone placed on coupler 1000 0 Hz 80 dBHL Right Earphonefaway From coupler OFF Left Earphone ON Cancel FIGURE 11 3 Earphone on Coupler Dialog Box Present the appropriate tone on the left earphone Once the measurement has been performed the prompt in FIGURE 11 4 will appear AUDit Manual Crosstalk Measurement Screen 11 3 Crosstalk Measurement Screen Left Earphone placed on coupler 1000 0 Hz 80 dBHL Right Earphonefaway From coupler OFF Left Earphone ON E Cancel FIGURE 11 4 Earphones Cross Talk Test Dialog Box Leave the left earphone on the coupler but present the tone on the right earphone ensuring that it is occluded and far enough away from the coupler to prevent acoustic pickup FIGURE 11 5 contains the next prompt Left Earphone placed on coupler 1000 0 Hz 80 dBHL Right Earphonefaway From coupler ON Left Earphone OFF Cancel FIGURE 11 5 Right Earphone on Coupler Dialog Box Replace the left earphone on the coupler with the right earphone The right earphone should still be driven with the tone The level will once again be measured Once this is done the last prompt FIGURE 11 6 is displayed Right Earphone placed on coupler 1000 0 Hz 80 dBHL Right Earphone ON Left Earphone away from coupler OFF Cancel FIGURE 11 6 Cross Talk Test Right Earphone on Coupler Dialog Box AUDit Manual AUDit
107. ree field at 0 degree incidence as well as monaural listening in sound field for 0 45 and 90 degree incidence These RETSPLs are used in AUDit to translate the measured sound pressure levels to hearing level Note that the prescriptions in Section 9 5 1 of the standard for sound field characteristics should be followed These include the requirement that the ambient noise in the sound field shall not exceed that specified in ANSI S3 1 1991 The ambient noise booth test in AUDit is helpful in making this determination To perform a test using speakers highlight the Speakers transducer list item left right or both binaural In this example the Left tab is selected An incidence angle of 0 45 or 90 degrees must be chosen so that the appropriate RETSPL correction is applied Note the headers at the top of the table The measured SPL value from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed The Right tab operates in exactly the same manner The Binaural tab has only one incidence angle selection zero degrees Click Measure All to perform all speech tests on the selected speaker s They are similar to the earphone speech tests An unsatisfactory reading is indicated by a large red X with values within parentheses Speech Test with Speakers AUDit Manual CHAPTER Audiometer Test Notes Before and during the calibration of an audiometer a visual inspection of its component
108. riate maximum output level of the audiom eter Click the Measure All button to perform a linear ity test on the right earphone AUDit then displays the prompt shown in Figure 8 2 to measure the lower end of the test range A Set 110 dBHL Right at 1000 0 Hz Cancel FIGURE 8 2 Level and Frequency Set Dialog Box Step 5 Set the audiometer to the prompted level and fre quency and then click OK There may be a delay while the measurement system gain is adjusted Once the noise floor has been measured e g 1 0 dB it will appear on the Linearity screen FIG URE 8 1 All level steps from the maximum level to the noise floor will be tested consecutively with AUDit prompts to change the level Steps which are out of tolerance will be indicated AUDit Manual by a large red X on the results screen as shown in FIGURE 8 3 a GSI 1716 5804 AUDit File Test View Report SLM Help BEA Kaaa aa EI Measurements Linearity Hearing Level Left Right Test Frequency 1000 0 v Direction Down Max dBHL 110 Dial step 5 Freg Modulation Dial Level Measured SPL Measured Step Deviation TargetStep Narrow Band Level 55 61 7 5 1 01 40to6 0 roan i Noise 50 56 6 5 0 00 40to6 0 R 51 6 02 40to60 46 4 01 40to6 0 41 3 37 2 AUDit 31 2 Transducers oe 2 dd Set 30 dBHL Left at 1000 0 Hz Insert Earphone 164 Circumaural Earphone 118 i Cancel TDH 50 Earphones Left 2 Right 1
109. rom ANSI S3 6 section 7 2 on the accuracy of sound pressure levels An unsatisfactory reading is indicated by a large red X It may be necessary to adjust the level by pressing the Adjust button AUDit Manual Mic Test 15 3 Adjust Level Measured SPL dBHL 92 8 72 8 Select Reading Basis 1000 Hz Frequency Overall C Weight FIGURE 15 3 Current Level Readings Screen A small dialog box appears FIGURE 15 3 which shows the current SPL and HL readings which the technician may adjust to bring the level within the listed target SPL range The adjustment does not affect the test result performed before To verify the adjustment the input may be retested with the Measure Selected button Tape CD A and Tape CD B Test 15 4 To perform a speech level test on the left earphone Tape CD A or B inputs highlight the appropriate subtest and press Measure Selected AUDit then displays the prompt shown in FIGURE 15 4 A Set Tape CD B 70 dBHL Left i Cancel FIGURE 15 4 Set Tape Level and Frequency Dialog Box Tape CD A and Tape CD B Test AUDit Manual Speech Noise Test AUDit Manual The speech material calibration signal should be provided to the appropriate input Set the listed level input and presentation on the audiometer then press OK The measured SPL is corrected for coupler microphone and other responses and should be 12 5 dB above the 1000 Hz RETSPL for the transducer in use See ANSI S3 6 2004 Section
110. rphone Freq Hz 125 250 500 750 1000 1500 2000 3000 4000 6000 Right Earphone Freq Hz 125 77 250 Pass Pass FAIL Pass Pass Pass FAIL Pass Hearing Level Te Measured SPL 117 5 96 6 83 9 79 4 78 3 78 1 81 4 79 6 80 4 82 8 Measured SPL 116 2 96 5 M 4 gt n Audiometer Report n a n a n a n a n a n a n a Hearing Level 72 5 69 6 70 4 70 4 70 8 70 6 72 4 68 1 68 4 66 8 Hearing Level 71 2 69 5 SPL Deviation SPL 25 0 4 0 4 0 4 0 8 0 6 24 1 9 1 6 3 2 SPL Deviation SPL 1 2 0 5 fam i Left Earphone HL Test i 85 0 50 0 T eee 75 0 Target dB HL 700 i e 112 0 to 118 0 ee 94 0 to 100 0 coo CO 80 5 to 86 5 Rg iB a t 5 425 250 500 750 1000 1500 2000 3000 4000 6000 i 10 OU 74 5 to 80 5 m Hearing 72 5 69 6 70 4 70 4 70 8 70 6 724 68 1 68 4 66 8 76 0 to 82 0 imit 76 0 76 0 76 0 76 0 76 0 76 0 76 0 80 0 80 0 80 0 78 5 to 845 Limit 64 0 64 0 64 0 64 0 64 0 64 0 64 0 60 0 60 0 60 0 79 0 to 85 0 81 0 to 91 0 Audiometer Frequency Target 112 0 to 118 0 94 0 to 100 0 s NUM 17 8 FIGURE 17 10 Data File Exported into Microsoft Excel Exporting Data AUDit Manual Stored Measurements Database Functions AUDit Manual The Larson Davis audiometer cali
111. rphones have two tabs Left and Right The bone vibrator has only one tab In this example the supra aural earphone 9 2 Harmonic Distortion Measurement Screen AUDit Manual AUDit Manual transducers will be calibrated The procedure is nearly the same for all transducers Remember to use the electrical terminal adaptor ADPO10 for frequencies above 5000 Hz Highlight the Supra aural Earphone transducer list item The Supra aural Earphone tabs will appear on the right part of the screen FIGURE 9 1 Click the Measure All button to perform a distortion test on the left earphone AUDit then displays the prompt shown in Figure 9 2 to measure the first frequency A Set 75 dBHL or max level Left whichever is lower at 125 Hz FIGURE 9 2 Level and Frequency Set Dialog Box Set the audiometer to the prompted level and frequency then press OK There may be a delay while the measurement system gain is adjusted When test frequencies greater than 5000 Hz it will be necessary to use the ADP010 and ADP006 combination to measure distortion on the electrical signal Harmonic Distortion Measurement Screen 9 3 GSI 1716 5804 AUDit DEK Harmonic Distortion Fund 2nd 3d 4th Sth THD Devi Max 121 3 572 731 485 609 27 25 116 1 484 665 438 542 22 25 Narrow Band Level 123 5 61 2 72 1 48 5 58 5 2 25 Broad Band Noise 116 8 522 637 50 1 2 25 Speech 25 Transducers Bone Vibrator In
112. s and control is necessary AUDit s Audiometer Test Notes screen FIGURE 16 1 affords a simple way to annotate the test report with comments and the condition of components or controls Beta Demo AUDit View Report SLM Help File gece Audiometer Test Notes Preferences FIGURE 16 1 Audiometer Test Notes Menu Item The Audiometer Test Notes screen is accessed from the main menu by pressing the Test Audiometer Test Notes selection Audiometer Test Notes 16 1 AUDit Manual Audiometer Test Notes Screen This screen has two tabs Visual Check and Comments A thorough visual and functional inspection of the audiometer and its accessories can be conducted with the help of the checklist in the first tab FIGURE 16 2 Visual Check Tab File Test View Report SLM Help 2 8 Fa 2 Visual Check Comments z gt 2 gt 0 aa 0 Earphone selector switch Response card Output seletor switch Ch 1 input selector switch Ch 2 input selector switch Function selector switch Microphone Monitor earphone speaker Manual pulse tone control VU meter Left earphone Tone On lamp Right earphone Left earphone cushion Right earphone cushion Left earphone cord Right earphone cord Headband Bone vibrator Bone vibrator cord Power cord Gi 3 G Power On lamp G G Attenuator Masking control Volume control G G O3 gt e e i
113. sert Earphone Circumaural Earphone TDH 50 Earphones Left 2 Right 1 AEC100 Coupler Mic 1316 Measure All Measure Selected Next Test Save Cancel FIGURE 9 3 THD Test Results Screen The results of the distortion measurement are listed in the tab FIGURE 9 3 with each harmonic s level in dB and the total harmonic distortion in percent Frequencies which are out of tolerance will be indicated by a large red X A failed frequency may be retested after adjustment by highlighting it and pressing the Measure Selected button Harmonic Distortion Measurement Screen AUDit Manual CHAPTER Pulse Test In some audiometry cases the presentation of pulsed tones is preferred The Larson Davis audiometer calibration sys tem performs accurate pulse measurements of the pure tone signal source by using digital signal processing techniques Requirements for the envelope of pulsed pure tone signals are listed in Section 7 5 4 of ANSI S3 6 2010 The relevant parameters for the automatically pulsed tones are defined below e Frequency fundamental rate of change of the pure tone signal in Hertz e Rise Time time in milliseconds between the 20 dB point referenced to the maximum level and 1 dB point on the rising edge of the pulsed signal envelope nomi nally between 20 and 50 ms e Fall Time time in milliseconds between the 1 dB point and 20 dB point on the falling edge of the pulsed signal envelope nominally between 20 and
114. surements Customer Boh Name From Date To Date Date May 17 2010 Jun 02 2010 Jun 02 2010 Jun 02 2012 FIGURE 17 13 Search Booth Measurements Dialog Box AUDit Manual Stored Measurements Database Functions 17 11 17 12 Entry fields for customer booth name calibration from to date and channel number can be used to search for the proper test When all fields are left blank all tests in the current database are displayed To find a certain test enter a search criterion in a field Alphabetical characters are not case sensitive in the search but otherwise search entries must be spelled exactly as they appear in the test Spaces before or after an entry are disregarded Dates may be entered in the following formats Apr 20 2010 or 04 20 10 The To Date must be equal to or later than the From Date Click on Update List to display the search results Retrieve the test by highlighting it and then clicking on Retrieve at the bottom of the dialog box Delete the highlighted test by clicking on Delete Deleted tests cannot be recalled Stored Measurements Database Functions AUDit Manual APPENDIX Glossary This appendix contains technical definitions of key acousti cal and vibration terms commonly used with Larson Davis instruments The reader is referred to American National Standards Institute document 1 1 1994 for additional defi nitions Specific use of the terms defined are in the main body of
115. te 6n e o e Power switch Fuse Tone interrupter G G G G D Q Q e e o o e e o te e Oi Tone reverse switch Freq selector switch F C C C C eer C Cc 9 C C e e e e Q G Ok Cancel FIGURE 16 2 Audiometer Test Notes Visual Check Tab This tab enumerates many components accessories and controls of the audiometer Some list items have properties which are governed by specifications in the ANSI S3 6 2004 standard Any non conforming or defective item should be checked by clicking the applicable radio button to the left of 16 2 Audiometer Test Notes Screen AUDit Manual Comments Tab AUDit Manual the item These items will appear in the test report and will be stored in the database The second tab allows the calibration technician to note any particularities of the tested system These comments also will appear in the test report and will be stored in the database Audiometer Test Notes Screen 16 3 16 4 Audiometer Test Notes Screen AUDit Manual Reports and Data Base Functions AUDit incorporates a number of features which help maintain a record of audiometer calibrations Tests performed can be printed immediately or stored for future hard copy Results may be kept in an indexed database with comprehensive search capabilities or exported to your external application in formatted output This chapt
116. ter data to add a new instrument Sound Level Meters Eek Calibrators Microphone Low Freq Pressure Response High Freq Pressure Response Grid Corrections Note To manually enter data for an instrument you must enter or change the serial number before you can add the instrument Manufacturer flasonDavis cunan Modet 377413 Microphones 2575 SN 1316 377413 SN 118894 Serial number 118894 2559 SN 3157 Sensitivity 13 45 mV Pa year month day Calibration due 2012 Oct 30 Delete Ok Cancel FIGURE 2 6 Microphone information Dialog Box 2 6 Entering Instrumentation Import Data AUDit Manual Note The 377AI3 requires the polarization voltage set for Electret in the 824 In SETUP SLM Settings set Transducer to Elctret For 2575 377A13 and 2559 microphones data can be imported directly from a csv file using the import data button After importing the csv file click OK to save the imported data to the AUDit database For other microphones frequency response information is available on the provided calibration chart and can be entered manually Some audiometric frequencies may not be listed exactly e g 200 Hz is listed as 199 53 Hz If the frequency labeled in the software is between two frequencies on the certificate you may wish to enter an interpolated value a 61 1 AUDit File Test View Report SLM Help il BIE a Instrumentation Select available Microphone or enter data to a
117. ternative is to repeat the measurement with the non activated calibrator left on top of the microphone Another is to do the booth test without a bias voltage on the microphone This has the effect of reduc ing its sensitivity and will show the electrical noise of the system The results of this first method are shown in FIG URE 4 11 The failed 125 Hz third octave measured SPL was 25 9 dB SPL Booth Ambient Levels Measurement Test Information SL Meter Preamp Mic Calibrator 125 8K Hz 250 8K Hz 500 8KHz _4 gt Show Fail Frequency X 125 250 X 500 800 1000 1600 2000 3150 4000 6300 8000 Measured SPL 25 9 Ears Covered MPANL Ears Not Covered MPANL C Show ANSI 30 0 24 0 C Show OSHA 20 0 16 0 Show Both 16 0 11 0 19 0 21 0 25 0 29 0 33 0 32 0 32 0 32 0 Ok Cancel FIGURE 4 11 Booth Ambient Levels Window As you can see the noise level at the third octave centered at 125 Hz is 4 4 dB SPL well below the failing ambient level Suspecting Instrument Noise 4 11 Hint To remove the bias voltage from the microphone stop the 824 and press Setup Right Arrow to modify the Audtest AUD settings Scroll to SLM press D Right Arrow and scroll down to modify SLM parameter Transducer Press the D Check key and per form an Overall Reset to select Elc tret Remember to rest the transducer to condnser before making new mea surements Edit Settings ii Aud Test AUD
118. tery cell use Audiometric test internal 824 firmware option BNC to 1 2 inch preamp thread adaptor with equivalent 47 pF capacitance for direct input to 824 1 2 inch preamp to 1 inch microphone thread adaptor audiometer earphone adaptor for electrical input to 824 6cc coupler NBS 9 A coupler with base coupler retaining ring micro phone cap mass and handle weight and pillow 1 2 inch MIC TO 1 inch CAL adaptor Artificial mastoid coupler and case IAMC493B 01 AMC493B operator manual MAE100 55 additional weight ring Precision microphone calibrator with 1 inch opening 1250 1 CAL250 operator manual Weather tight hard carrying case USB to serial adaptor 10 foot microphone extension cable Audiometer calibration software including IAUDit 01 software operator manual and media 1 4 Unpacking and Inspection AUDit Manual SYS010 with AEC201 A Precision integrating sound level meter including PRM902 1 2 inch preamplifier with 7 pin LEMO connector PSA027 90 264 Volt to 12 V Power supply BAT010 nickel metal hydride AA rechargeable battery pack CBLOO6 serial communications cable with 9 pin D connector CBL042 stereo phone plug to dual BNC output cable 1824 01 operator manual 1824 02 training manual 1824 03 firmware upgrade instruction sheet SWW 824 F utility software CD WS001 3 1 2 inch foam windscreen AM814 06 Neg Pos AA term Spring Assy for individual AA battery cell use Audiometric test internal 824
119. the text Average Sound Level Layg It is the logarithmic average of the sound during a Measure ment Duration specific time period using the chosen Exchange Rate Factor Exposure to this sound level over the period would result in the same noise dose and the actual unsteady sound levels If the Measurement Duration is the same as the Criterion Duration then Lays Lpwa c T 1 Live qLo gy al 10 T L L qt where the Measurement Duration specified time period is T T T and q is the Exchange Rate Factor Only sound lev els above the Threshold Level are included in the integral Standard ANSI 12 19 Calibration Adjustment of a sound or vibration measurement system so that it agrees with a reference sound or vibration source It should be done before each set of measurements Decibel dB A logarithmic form of any measured physical quantity typi cally used in sound and vibration measurements Whenever the word level is used it implies this logarithmic form The relationship is relatively simple but the mathematics can AUDit Manual Glossary A 1 become complex It is widely used and was developed so that the very wide range of any quantity could be repre sented more simply It is not possible to directly add or sub tract physical quantities when expressed in decibel form The word level is always attached to a physical quantity when it is expressed in decibels for example L represents the sound pressure level
120. tion 4 6 Booth Test or Ambient Noise Level Test AUDit Manual SLM Calibration Measured SPL Ref Level Difference 114 0 00 Calibrator SN Model Manufacturer Larson Davis 5019 CAL250 y Microphone SN Model Manufacturer Larson Davis Model 2575 Serial Number 1316 1316 2575 bd Model CAL250 Output Level 114 0 Serial Number 5019 Frequency 251 2 Set Calibration Close Hint Do not hold or bump the cali brator during calibration Vibrations may affect readings All measure ment system components should have reached a stable temperature before calibrating Your calibrator should remain on for the duration of the calibration about 30 seconds If its battery is low replace it to extend the tone duration AUDit Manual FIGURE 4 6 SLM Calibration Window AUDit will display the SLM Calibration dialog box Select your calibrator and microphone in the pull down menus Note that the current level and the difference between it and the calibrator output level are displayed at the top of the box Figure 4 6 You may use this display to check calibra tion without changing it then click on Close to exit To change calibration click Set Calibration System Acoustic Calibration 4 7 Performing a Booth Test Once the SLM has been calibrated the ambient noise levels can be measured Select the Test Booth Test menu item to display the Booth Ambient Levels Measurement screen GSI 176
121. udiometer calibration process highlight the Frequency test with the pointer and press the Go To Measurement button If you are already in a test screen press the same test in the Measurements window Note that the SLM should be calibrated before a measurement is performed Frequency Test with Earphone Transducers Frequency Accuracy IV Show Applied Corrections Dial Frequency Measured Frequency Deviati Target Frequency Freq 125 250 Transducers Insert Earphone Circumaural E arphone 125 7 123 8to 126 2 1 0 251 5 247 5to 252 5 1 0 503 0 i 495 0 to 505 0 1 0 755 8 7 742 5to 757 5 1 0 1006 2 990 0to 1010 0 1 0 1507 4 1485 0to 1515 0 1 0 2008 0 f 1980 0 to 2020 0 1 0 3014 0 2970 0 to 3030 0 1 0 3960 0 to 4040 0 1 0 5940 0 to 6060 0 1 0 7920 0 to 8080 0 TDH 50 49 Earphones Left 2 Right 1 AEC201 Coupler Mic 118894 Measure All Measure Selected Next Test Save Cancel 01 08 2013 03 16 AM FIGURE 7 2 Frequency Test Screen 7 2 Frequency Test with Earphone Transducers AUDit Manual Checking the Show Applied Correc tions on this tab displays the Freq column which shows the percentage difference allowed for the associated frequency to pass the test AUDit Manual The Frequency test screen FIGURE 7 2 is the same for all earphone types On the left below the measurement table the transducers list contains supra aural insert and circumaural earphones All earphones types have two
122. ufficient number of them to cover the usual range of frequencies encountered in sound and vibration measurements The frequency chosen to describe the band is that of the center frequency Note table in Fre quency Filter Frequency Weighting A special frequency filter that adjusts the amplitude of all parts of the frequency spectrum of the sound or vibration unlike band pass filters It can be composed of one or more of the following types A Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to low levels of sound This weighting is most often used for evaluation of environmental sounds See table below B Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to higher levels of sound This weighting is seldom used See table below C Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to high levels of sound This weighting is most often used for evaluation of equipment sounds See table below Flat Weighting A filter that does not adjust the levels of a A 5 Leq Level dB A 6 frequency spectrum It is usually an alternative selection for the frequency weighting selection Center Frequencies Hz Weighting Network Frequency Response 1 3 Octa
123. uld extend approximately 5 mm above the threaded ridge The insulator around it should be free of dust and other particles Please do not handle the contact and protect it by keeping the coupler cap on whenever a micro phone is not installed Install the 1 microphone LD Model 2575 or equivalent on the center of the artificial ear base The microphone should install easily screw it fin ger tight FIGURE 5 7 FIGURE 5 7 2575 Microphone and AEC100 Step 6 Insert the 1 2 microphone preamplifier LD Model PRM902 or equivalent gently in the side port until its threads contact those of the base The preamplifier should install easily screw it finger 5 6 Audiometer Test System Assembly AUDit Manual tight FIGURE 5 8 Connect the instrument cable to the preamplifier The coupler is now ready for level calibration FIGURE 5 8 Preamp connecting to AEC100 and Extension Cable AEC100 Acoustic Calibration It is necessary to remove the calibra Level calibration is performed with the Larson Davis Model tor 1 2 inch adaptor ADPO19 ring CAL250 precision calibrator It offers a level of 114 dB with from the CAL250 to allow the one an accuracy of 0 2 dB at 251 2Hz To calibrate the inch microphone to fit inside the cal measurement system and artificial ear follow the procedure ibrator one inch opening below Step 1 Assemble the coupler as described in the AEC100 Acoustic Calibration on page 5 7 section above The coupler b
124. usly entered into the instrumentation database is available for selection in these dialogs To use a new piece of equipment in a test first enter it into the instrumentation database then it can be selected here Mastoid Tab File Test Yiew Report SLM Help Djs Malia BE 2 Setup Items Test Location Microphones Audiometer Speakers Model Manufacturer Select Instrumentation ZIM Sound Level Meter Calibrato Preamp Earphones gt cea gates Serial Number 5339 AMC493B Larson Davis Calibration Due 2012 01 01 Coupler for Larson Davis Mastoid C AEC100 IEC 60318 3 C AEC101 IEC 60318 1 AEC201 IEC 60318 1 FIGURE 3 3 Mastoid Selection Tab AUDit Manual The serial number is selectable from a drop down list of the previously entered serial numbers which determines the Model and Manufacturer The Larson Davis AMC493B and B amp K 4930 artificial mastoids are supported by AUDit The Equipment 3 3 two boxes at the bottom of the screen are active only for the appropriate mastoid Coupler for Larson Davis Mastoid Since the Larson Davis AMC493B artificial mastoid requires corrections based on the coupler with which it is used these radio buttons selects either the Larson Davis Model AEC201 or AEC100 coupler Mic used to calibrate the SLM This box is only enabled with the Bruel amp Kjaer artificial mastoid It is used to specify which microphone will be used to calibrate the SLM
125. ve 1 Octave A B C 20 50 4 24 2 6 2 25 44 7 20 4 4 4 31 5 31 5 39 4 17 1 3 0 40 34 6 14 2 2 0 50 30 2 11 6 1 3 63 63 26 2 9 3 0 8 80 22 5 7 4 0 5 100 19 1 5 6 0 3 125 125 16 1 4 2 0 2 160 13 4 3 0 0 1 200 10 9 2 0 0 250 250 8 6 1 3 0 315 6 6 0 8 0 400 4 8 0 5 0 500 500 3 2 0 3 0 630 1 9 0 1 0 800 0 8 0 0 1000 1000 0 0 0 1250 0 6 0 0 1600 1 0 0 0 1 2000 2000 1 2 0 1 0 2 2500 1 3 0 2 0 3 3150 1 2 0 4 0 5 4000 4000 1 0 0 7 0 8 5000 0 5 1 2 1 3 6300 0 1 1 9 2 0 8000 8000 1 1 2 9 3 0 10000 2 5 4 3 4 4 12500 4 3 6 1 6 2 16000 16000 6 6 8 4 8 5 20000 9 3 11 1 11 2 See Energy Equivalent Sound Level Sound Level Energy Average and Time Weighted Average A descriptor of a measured physical quantity typically used in sound and vibration measurements It is attached to the name of the physical quantity to denote that it is a logarith mic measure of the quantity and not the quantity itself The word decibel is often added after the number to express the AUDit Manual Measurement Duration T Microphone Guidelines AUDit Manual same thing When frequency weighting is used the annota tion is often expressed as dB A or dB B The time period of measurement It applies to hearing dam age risk and is generally expressed in hours Standard ANSI 12 19 Microphone Types A device for detecting the presence of soun
126. w Applied Corrections option displays the following columns In Lvl RETFL FL Mast Mic T H and P The list of the active frequencies selected earlier in the audiometer setup appears in the right window Placement of the bone vibrator affects output Select the proper option Mastoid or Forehead Note the headers at the top of the table The measured SPL value from the sound level meter is converted to hearing level and the deviation from the target SPL is displayed 6 8 Hearing Level Test AUDit Manual Not all frequencies have a valid The row of buttons at the bottom of the screen allows the RETSPL i e 160 Hz technician to e Adjust adjust the audiometer in real time if a precision output level adjustment is available e Measure All measure all frequencies sequentially with software prompts e Measure Selected measure only the currently highlighted frequency with software prompts e Next Test move to the next measurement in the Measurements list in the upper left window OK end the current test e Cancel cancel the current test Press Measure All to perform a hearing level test on the bone vibrator If you are using a Larson Davis mastoid you will be prompted to enter temperature and humidity values Figure 6 9 used within the software for artificial mastoid corrections Temperature Humidity Humidity 45 Temperature 22 0 C Pressure fior 30 in mmHg or kPa FIGURE 6 9 Temperature Hu
127. y the main menu 1 8 Starting the Software AUDit Manual Initial Configuration Before performing a measurement a few items need to be configured in the AUDit software This chapter covers setting up a database configuring the system printer entering calibration instrumentation information and other user preferences Creating a Database Change database The measurement database is a Microsoft Access compatible file which contains information about calibration instruments as well as audiometer and booth test results During installation you may have elected to create a blank database by default Auditdb mdb in the current directory If so you may skip this section To create a new database click File Change Database in the AUDit menu to open the Change Database dialog box then click Browse Enter name of new database and click connect or press browse Selecting an existing database in the Browse dialog will open it Database CD ocuments and Settings All Users Application Connect Cancel FIGURE 2 1 Change Database Dialog Box AUDit Manual Initial Configuration 2 1 2 2 The Open dialog box will appear allowing you to select a database To create a database enter a new database name and select open Look in 5 auni 5a EB DAO Setup FAN suditdb mdb Filename auditdb mdb Files of type Access Database Files mdb v Cancel H FIGURE 2 2 Open Dialo

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AUDiT™ Software Operation Manual