AEC101 Manual CH 2.book
Contents
1. Electroa coustics Simulators of human head and ear Part 1 Ear simulator for the calibration of supra aural earphones when used with the Larson Davis Model 2559 1 2 preci sion air condenser microphone International Standard IEC 60318 2 1998 08 Electroa coustics Simulators of human head and ear Part 2 An interim acoustic coupler for the calibration of audiomet ric earphones in the extended high frequency range when used with the Larson Davis Model 2559 1 2 preci sion air condenser microphone and Type 1 and Type 2 adapter plates American National Standards Institute ANSI S3 7 1995 Methods for Coupler Calibration of Earphones Section 5 4 IEC coupler for supra aural earphones described in Annex C normative Calibration of circumaural earphones for extended high fre quency testing Physical Acoustic volume tolerances Microphone mounting thread Preamplifier mounting thread 0 4606 60 UNS 2B Maximum diameter 82 mm 3 2 Height 50 mm 2 0 without weight and earphone retainer 119 mm 4 7 with earphone retainer ring Weight 1 4kg 3 2 Ib Type 1 Plate Larson Davis Model MAEC101 06 Maximum diameter 120 mm 4 72 Height 10 8 mm 42 Weight 260 g 57 Ib Typical earphone Sennheiser HDA200 Type 2 Plate Larson Davis Model MAEC101 07 Maximum diameter 78 5 mm 3 09 Typical earphone Koss HV 1A A 2 AEC101 User Manual September 8 1999 Weights S2. Follow general electrical precautions for working with ener gized low voltage 200V maximum circuits The micro phone bias voltage may be present on exposed microphone contacts Do not turn on the Model 2900 analyzer until all connections have been made All other standard safety pro cedures should be followed The following equipment is required for this calibration pro cedure The response of the Model 2575 microphone used as a driver should be known with the appropriate degree of accuracy Part Number Description Comments 2900 2800 OPT 11 Analyzer and signal generator Provides excitation voltage and measurement ESOM Cr MAEC101 01 and 03 Coupler housing and tuning AEC101 stainless steel upper assembly cavity MAEC101 50 Coupler tuning tool AEC101 base MAEC101 04 may be used if no adjustment is necessary MAECI01 51 Driver tuning tool Cylindrical apparatus for mounting excitation driver on test AEC101 2559 1 2 precision microphone AEC101 cavity microphone Before beginning this procedure the Coupler subassembly should be assembled Verify that the stainless steel port tube is securely mounted in the coupler housing MAEC101 01 and that its hole is open and free of blockage Verification The following procedure may be used to measure the char acteristic frequency response of the AEC101 coupler Step 1 Assemble the coupler configuration shown in Fig ure 1 The assembly may be oriented vertically
3. Testing Transducers en 3 1 transducer ssh nai aline nes 3 1 Typed Plate shine AA 2 Type 2 Plate ss AA 2 W Weights 2 2223 ern AA 3
4. within its frequency response This coupler is part of the Larson Davis family of products for audiometer calibration and electro acoustic test With the other components of LD audiometer calibration systems it provides a durable means of calibrating and testing many types of electro acoustic transducers It may also be used for production testing where correlation between the coupler and real ear response is not a requisite August 26 1999 Introduction 1 1 Construction Standards The AEC101 is composed of three cavities coupled by pre cise acoustical volumes The main cavity includes a 1 2 microphone LD 2559 not included which is connected to the preamplifier inserted in the base of the coupler via a teflon insulator with gold plated contacts and stainless steel spring loaded pin Major mechanical parts are made of non magnetic stainless steel for hardness finish and long lasting quality The base has a non skid rubber bottom and a vibra tion isolation pad is provided with the system In use a supra aural earphone is securely contained by an earphone retainer ring made of durable black anodized alu minum Clamping force is supplied by a stainless steel weight 4 5 N lowered in the retainer ring This approach adapts to different earphones and avoids having to adjust complex spring loaded mechanisms The AEC101 also includes two adapter plates and a heftier flexible bag weight 9 5N required for circumaural ear phone
5. 0 7 The handle should screw in securely 2 2 AEC101 User Manual September 8 1999 Step 4 If installed remove the coupler from the artificial ear base by gently unscrewing it counterclock wise Step 5 Inspect the spring loaded contact at the center of the base visually It should extend approximately 5 mm above the threaded ridge The teflon 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 6 Working over the cushioned pad ACC001 install the 1 2 microphone LD Model 2559 or equivalent on the center of the artificial ear base The microphone should install easily screw it fin ger tight figure 2 2 Figure 2 2 Microphone installed on AEC101 Step 7 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 2 3 September 8 1999 AEC101 IEC 318 Coupler Initial Inspection and Assembly 2 3 NOTE When removing the preamplifier unscrew it by holding on its body not the connector sleeve Figure 2 3 Preamp being installed in the AEC101 Step 8 Connect the instrument cable to the preamplifier The coupler is now ready for level calibration AEC101 IEC 318 Coupler SPL Calibration NOTE You will need to install the Level calibration
6. AEC101 IEC318 Artificial Ear Coupler User Manual O Larson Davis 1681 West 820 North Provo UT 84601 1341 Phone 801 375 0177 FAX 801 375 0182 www larsondavis com IAEC101 01 Rev A AEC101 User Manual Trademarks PC is a trademark and IBM is a registered trademark of International Business Machines Corporation Intel is a registered trademark of Intel Corporation Windows 95 Windows 98 and Windows NT are registered trademarks of Microsoft Corporation Other product and company names may be mentioned in this manual which are trademarks of their respective owners Disclaimer Even though Larson Davis has reviewed thiedocumentation Larson Davis makes no warranty or rep resentation either expressed or implied with respect to this 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 Larson Davis Support Policy Please retain the serial number and purchase date of your AEC101 You may be asked to provide this information when contacting Larson Davis for service or technical support Warranty Larson Davis warrants this product to be free from defects in material and workmanship for two years from the date of original purchase During the first year of warranty period Larson Davis will repair or at its option replace any defec tive componen
7. ency response of the AEC101 coupler This response should compare to the acoustical response indicated in the standard B 4 The coupler adjustment screws are sealed in position with locking compound Under normal circumstances they should not require adjustment Tuning adjusting the cou pler s tuning screws is performed with the equipment and setup described in this appendix Please contact Larson Davis for information about this procedure AEC101 User Manual August 26 1999 A About this manual AEC100 NBS 9 A ANSI 53 7 199 ss AA 1 Assembly him Audiometer Calibration C Calibration Environmental Conditions Circumaural earphone Compatibility Connecting the PC Construction ooo cece cecccccestececeseeesteeeeens E Earphone Frequency Response Environmental eee TEE 60378145 ieee eee TOO S nee mn lt NT IEC 6031822 ane TEC 603 1853 se a Initial Inspection eneeen K Koss HV TA an a aa a Measurements neennen Microphone mounting thread P Parts List Production Testing eeee SPARKTM 706RC 705 703 703 and BLAZETM USER MANUAL Index S Sennheiser HDA200 oaeee 3 1 SRC20 mem nn ee nm Sed 1 4 Standards Ra 1 2 AA 1 Supra aural earphone 3 1 T Telephonics TDH 39 49 50 3 1 Test Configurations eeneee 3 1 Testing Circumaural Earphones 3 4
8. hone Frequency Response Production Testing 1 4 AEC101 IEC 318 Coupler Initial Inspection and Assembly 2 1 AEC101 IEC 318 Coupler SPL Calibration ss 2 4 Testing Transducers with the AEC101 3 1 Audiometer Transducer Test Configurations en 3 1 Testing Supra Aural Earphones with the AECIO1 u ucessenseesensersersersnennne en 3 2 Testing Circumaural Earphones with the AEC101 en 3 4 Environmental conditions ss 3 4 Test Eonfigur tions s 2 4 2268 cabio gica ndo dbewtessdosbeassssedsaea seen 3 4 AEC101 Specifications ccscssssscssssscssssscsssescssssscssssscsssers A A T Standards bessert rin Diss eisen ner AA I Physical as ns in nr ann Sina dh AA 2 AEC101 Verification or Calibration see AB 1 Safety Pr cautions ist Bess SR aia eam aS AB 1 Equipment amp Materials 2eme ie den em sten AB 1 Verilication ss RR PAREI E DR PR RO PADRE DPS RAN abate Nien RR AB 2 Tunes BE ea a Teia Rene de Rae Sn AB 4 AEC101 USER MANUAL Introduction The AEC101 IEC 318 Artificial Ear Coupler Thank you for choosing the Larson Davis AEC101 IEC 318 Artificial Ear Coupler The AEC 101 coupler is an ear simula tor covering the frequency band from 20 to 10000 Hz which has been designed for the calibration of supra aural ear phones used in audiometry and telephonometry applied to the ear without acoustical leakage The AEC101 allows accurate and repeatable measurements
9. ication for Audiometers Earphone Frequency Response Production Testing As is the case with other artificial ear couplers the AEC101 approximates the average human ear only for a limited fre quency range and with certain earphones The measured responses may be significantly different from one earphone type to another However an exact correlation is not always required for production testing It is possible to use the AEC101 as part of an accurate system for production testing of earphones or other electro acoustic transducers Such a system may consist of the following components e Test earphone and adapter to AEC101 e Larson Davis Model AEC101 coupler e Larson Davis Model 2559 1 2 microphone e Cable from earphone connector to BNC output of source e Larson Davis Model SRC20 synthesized signal source e Precision amplifier if required e Precision sound level meter such as Larson Davis Model 824 Lite or 824 with frequency analysis capability Frequency response level linearity and harmonic distortion can be measured using the signal generation capability of the SRC20 the coupler and precision sound level meter AEC101 User Manual August 26 1999 September 8 1999 AECIOIL IEC 318 Coupler Initial Inspection and Assembly The AEC101 IEC 318 Coupler is available in a variety of configurations You may have purchased the coupler alone with various accessories or within a complete audiometer test system In
10. is performed with the Larson Davis Model adapter ADP019 into the CAL250 in CAL250 precision calibrator It offers a level of 114 dB with order to calibrate 1 2 inch microphones an accuracy of 0 2 dB at 250Hz 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 fol low the procedure below Step 1 Assemble the coupler as described in the Initial Inspection and Assembly section above The cou pler base should rest on the isolation pad and ambient noise and vibration should be minimized 2 4 AEC101 User Manual September 8 1999 NOTE Do not remove the microphone Step 2 Place the calibrator opening on the microphone grid cap and seat it fully figure 4 4 Figure 2 4 Installing the CAL250 on AEC101 Step 3 Activate the calibrator as prompted by the soft ware and verify the stability of the indication on the measurement system figure 4 5 Do not hold the calibrator during calibration Its tone will last about one minute depending on the battery and will turn off automatically Figure 2 5 CAL250 being activated on AEC101 September 8 1999 AEC101 IEC 318 Coupler Initial Inspection and Assembly 2 5 2 6 AEC101 User Manual September 8 1999 Testing Transducers with the AECIOI This chapter covers test configurations for the audiometer transducers which can calibrated with the LD AEC101 Please contact Larson Davis if yo
11. leakage from the coupler through paths other than the capillary leak hole Screw the coupler over the base figure 3 1 until finger tight The sealant should not affect the volume of the cavity or occlude the leak hole Figure 3 1 Coupler being installed on AEC101 Step 4 Place the black conical ring figure 3 2 on the top of the coupler Figure 3 2 Black Conical ring installed on AEC101 3 2 AEC101 User Manual September 8 1999 Step 5 For headphones with a very stiff ear cap apply a thin less than Imm film of sealant or rubber sheet on the contact area between coupler and ear phone Step 6 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 3 3 Figure 3 3 Retainer ring being installed on AEC101 Step 7 Lower the mass by its handle to the top of the ear phone figure 3 3 Figure 3 4 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 September 8 1999 Testing Transducers with the AEC101 3 3 Testing Circumaural Earphones with the AEC101 Environmental conditions met Condition Range in ANSI S3 6 1996 Range in IEC 318 1 1998 Annex C Clause 6 Calibration 98 to 104 kPa 98 3 to 104 3 kPa 18 to 26 degrees C 20 to 26 degrees C Circumaural earphones are available for audiometer
12. mall mass with handle supra aural earphones 460 g 1 01 Ib Large mass circumaural earphones 970 g 2 14 Ib Calibration Environmental Conditions Reference ambient pressure Reference temperature Reference relative humidity IEC 318 1 Calibration should be performed at the above conditions within 3 0 kPa 3 0 C and 20 R H or else actual values shall be stated Compatibility Microphone Larson Davis Model 2559 1 2 condenser microphone of Type WS2P per IEC 61094 4 Preamplifier Larson Davis Model PRM902 PRM904 PRM900B or C PRM826 Type Plate Larson Davis Model MAEC101 06 Type 2 Plate Larson Davis Model MAEC101 07 Please contact Larson Davis for compatibility with other accessories September 8 1999 A 3 A 4 AEC101 User Manual September 8 1999 APPENDIX Safety Precautions AECIOI Verification or Calibration This appendix describes the method used to verify calibra tion and overall stability of the Larson Davis AEC101 IEC 318 coupler Some custom components are required for this procedure They are available from LD Please contact Lar son Davis if you have any questions about this procedure This procedure uses the Larson Davis Model 2900 real time analyzer which provides the input signal and measures the AEC101 output Refer to the 2900 User s Manual for com plete instructions on this instrument Equipment amp Materials August 26 1999
13. on and Certification Services Larson Davis offers NIST traceable calibration services compliant with ISO 10012 Remember that your microphone and preamplifier are an important part of your acoustic measurement system and it is important that your system is properly calibrated by people who understand the complexities of these components Larson Davis encourages you to return your system to the factory for calibration each year thus validating the accuracy and quality of your measurement with a factory calibration cer tificate Please refer to the Larson Davis price list for details of cost or contact the factory or your Lar son Davis Representative for details In many cases engineering improvements and firmware upgrades are included with calibration at no additional cost As an additional incentive to take advantage of our calibration services Larson Davis will extend the labor warranty by another year following a paid calibration certification AEC101 User Manual Chapter 1 Chapter 2 Chapter 3 Appendix A Appendix B AEC101 USER MANUAL Table of Contents Introduction 1 1 The AEC101 IEC 318 Artificial Ear Coupler ss 1 1 CONSTTU TION a ae ter RAS PO EO PERES 1 2 Standards 22 san tree coco dbase ties db peida ato seconageerictvesgseesna 1 2 About this manual inneren 1 3 Measurements ca coe ak annee tora qo nas ais Sa ets mens 1 3 Audiometer Calibration ss 1 3 Earp
14. or horizontally The driver tuning tool must be held tight against the coupler rubber bands or clamps B 2 AEC101 User Manual August 26 1999 work well Isolate the assembly from external sound or vibration e g on soft foam blocks in a very quiet environment Mic adapter connector LD ADP051 1 to 1 2 adapter LD ADP042 or ADP008 1 microphone LD 2575 Driver tuning tool LD MAEC101 51 Coupler 1 2 microphone LD 2559 Coupler tuning tool LD MAEC101 50 1 2 preamp LD PRM900C or equiv Figure 1 Coupler Test Configuration Step 2 Connect the coupler configuration to the analyzer and signal generator as shown in Figure 2 August 26 1999 B 3 Tuning i Mic Mic Extension AC DC Extension Cable ACDC Adder Cable OUT LD ADPoso AC IN DC IN 1 8 Phone to BNC Mic Extension Cable SOURCE 2 1 OUTPUT PREAMP INPUTS Test 2900 with Function Generator Figure 2 Coupler connection to analyzer Step 3 Use the Model 2900 analyzer and its internal noise generator to perform a frequency response of the AEC101 coupler The internal noise generator may be set to a sweeping sine wave test with appropriate sweep rate and level to measure the response with the analyzer s filters When cor rected for the frequency response of the driver sec tion the measured spectrum provides the frequ
15. p 4 For earphones designed to be calibrated with a Type 1 adapter such as the Sennheiser HDA200 install the Type 1 adapter on the coupler with the 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 3 6 Figure 3 6 AEC101 with Type 1 Adapter installed September 8 1999 Testing Transducers with the AEC101 3 5 3 6 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 3 7 Figure 3 7 Type 2 adapter adapter installed on AEC101 Step 6 Center the test earphone on the coupler or place it as recommended if the cushion is asymmetrical AEC101 User Manual September 8 1999 Step 7 ANSI S3 6 1996 requires a static force of 9 to 10 N on the earphone during calibration Use the large weight figure 3 8 Figure 3 8 Sennheiser earphone and weight being installed on AEC101 The coupler and earphone are now ready for measurement Set tone type level and presentation and make the reading on the measurement system September 8 1999 Testing Transducers with the AEC101 3 7 3 8 AEC101 User Manual September 8 1999 APPENDIX Standards AECIOI Specifications Fulfills the requirements of September 8 1999 International Standard IEC 60318 1 1998 07
16. s for the test and calibration of earphones Appendix A Calibration Method description of the proce dure used to calibrate and verify the AEC101 stability Appendix B Specifications Audiometer Calibration August 26 1999 The Larson Davis AEC101 IEC 318 Artificial Ear Coupler may be used for a number of precision electro acoustic test applications such as audiometer calibration and earphone frequency response production testing The accuracy of an individual s hearing evaluation is extremely important for clinical legal as well as personal reasons The audiometers used to quantify hearing loss are complex instruments They include signal generation pre sentation and electro acoustic components which must be verified periodically to ensure accuracy and repeatability Introduction 1 3 Audiometers are often located in test areas which must also be tested for ambient noise and it is preferable not to remove them from their installation Therefore portable cal ibration systems are indicated The Larson Davis AEC101 IEC 318 Artificial Ear Coupler is ideal for a lightweight portable calibration system It may be added to the LD SYS008 and SYS009 audiometer cali bration systems which include a precision sound level meter System824 and software AUDit to perform exhaustive calibration according to the American National Standards Institute ANSI S3 7 1995 Methods for Coupler Calibration of Earphones and S3 6 1996 Specif
17. s using extended high frequencies from 8000 to 16000 Hz These 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 Interim RETSPLs for two circumaural earphones are listed in Annex C of ANSI S3 6 1996 the Sennheiser HDA200 and Koss HV IA It is recommended from various standards that the extended high frequency calibration of circumaural earphones be per formed when the following environmental conditions are Relative Humidity 30 to 80 RH 30 to 70 RH Any condition not met Calibration is not allowed State actual values Test Configurations 3 4 The following steps are suggested for circumaural earphone audiometer calibration with the AEC101 Step 1 Assemble the coupler as described in the Initial Assembly above 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 the Calibration chapter AEC101 User Manual September 8 1999 Step 3 As desired apply sealant on the lower portion of the microphone to prevent air leakage from the coupler through paths other than the capillary leak hole Screw the coupler over the base figure 3 5 The sealant should not affect the volume of the cavity or occlude the leak hole Figure 3 5 Coupler being installed on AEC101 Ste
18. t s without charge for parts or labor if the unit is returned freight prepaid to an autho rized service center The product will be returned freight prepaid During the second year warranty period there will be no charge for replacement parts provided the product is returned to a Larson Davis repair facility Product defects caused by misuse accidents or user modification are not covered by this warranty The warranties described above are exclusive and in lieu of all other warranties whether statutory express or implied including but not limited to any implied warranty of merchantability or fitness for a particular purpose and all warranties arising from the course of dealing or usage or trade The buyer s sole and exclusive remedy is for repair or replacement of the non conforming product or part thereof or refund of the purchase price but in no event shall Larson Davis its contractors and suppli ers be liable for any special indirect incidental or consequential damages whether the claims are based in contract in tort including negligence or otherwise with respect to or arising out of the prod uct furnished hereunder Representation and warranties made by any person including authorized dealers representatives and employees of Larson Davis which alter or are in addition to the terms of this warranty shall not be binding upon Larson Davis unless in writing and signed by one of its offic ers AEC101 User Manual Calibrati
19. testing The AEC101 was designed to achieve the characteristics defined in International Electrotechnical Commission IEC 60318 1 1998 Ear simulator for the calibration of supra aural earphones The AEC101 coupler also meets the requirements of the American National Standard ANSI S3 7 1995 Methods for Coupler Calibration of Earphones section 5 4 It is used with the Larson Davis 2559 precision 1 2 random incidence microphone and a measuring system typically the PRM902 preamplifier and System 824 real time analyzer sound level meter With the help of adapter plates described in IEC 60318 3 An interim acoustic coupler for the calibration of audiometric earphones in the extended high frequency range and in ANSI S3 7 1995 Methods for Coupler Calibration of Ear Phones Annex C the AEC101 may also serve to calibrate AEC101 User Manual August 26 1999 About this manual specific high acoustic damping earphones in the range from 8 kHz up to 16 kHz Measurements This manual describes the care and usage of your AEC101 IEC 318 Artificial Ear Coupler and accessories The follow ing subjects will be covered Chapter 1 Introduction overview of AEC101 properties and standards Chapter 2 Initial Inspection Assembly and Calibration initial familiarization with the AEC101 components assem bly to a typical measurement system System824 and cali bration Chapter 3 Testing Transducers with the AEC101 setup and procedure
20. this chapter the initial inspection of the AEC101 will be covered You will also assemble an AEC101 and connect it to a measurement system in this case the System 824 precision real time sound level meter analyzer For this you will need PRN CAL250 Precision SPL calibrator with 114 dB SPL output at 250 Hz with 1 to 1 2 calibrator opening adaptor WARNING Before continuing ensure that the 824 SLM is turned off Sensitive circuitry may be adversely affected by transients during assembly if the 824 is on The 824 should remain off until the system is fully assembled AEC101 IEC 318 Coupler Initial Inspection and Assembly 2 1 The AEC101 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 in the capillary leak hole is present with no other obstructions figure 2 1 Leak Hole Figure 2 1 AEC101 with coupler leak hole Step 3 Check the threaded hole on the weight assembly SAEC100 01 for obstructions and screw in the mass handle MAEC10
21. u have any system assem bly questions not covered in this manual Audiometer Transducer Test Configurations The table below lists some typical audiometer transducers many of which are covered in specifications such as Ameri can National Standards Institute Specifications for Audiom eters S3 6 1996 These test setups are covered in greater detail in subsequent sections Supra aural earphone Telephonics TDH 39 AEC100 NBS 9 A cou Use 4 5 N weight Test 49 50 pler or AEC101 IEC 318 up to 8000 Hz artificial ear Circumaural earphone Sennheiser HDA200 AEC101 IEC 318 artifi Use 9 10N weight cial ear with Extended frequency tests MAEC101 06 Type 1 up to 16000 Hz may be adaptor plate performed Circumaural earphone Koss HV IA AEC101 IEC 318 artifi Use 9 10N weight cial ear with Extended frequency tests MAEC101 07 Type 2 up to 16000 Hz may be adaptor plate performed September 8 1999 Testing Transducers with the AEC101 3 1 Testing Supra Aural Earphones with the AEC101 The following steps are suggested for audiometer calibration with the AEC101 Step 1 Step 2 Step 3 Assemble the coupler as described in the Initial Assembly Chapter The coupler base should rest on the isolation pad and ambient noise and vibra tion should be minimized Perform a calibration of the system as described in the Calibration Chapter above As desired apply sealant on the lower portion of the microphone to prevent air
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