GRAS 45CA Headphone Hearing Protector Test Fixture Instruction Manual

Instruction Manual
GRAS 45CA Headphone/Hearing-protector Test Fixture

LI0187 – 01 June 2022

Revision History
Any feedback or questions about this document are welcome at gras@gras.dk.

pressure equalization added.
3| 6 February 2018| 45CA-7 to 45CA-10 configurations with high-frequency ear simulator added
5| 3 May 2019| Table with correction factors added.
6| 29 August 2019| Hi-Res Configurations added.
7| 1 June 2022| TEDS functionality section added.

Copyright Notice
© 2016 – 2022 GRAS Sound & Vibration A/S
www.GRASacoustics.com
Any technical documentation that is made available by GRAS is the copyrighted work of GRAS and is owned by GRAS.
The content in this document is subject to change without notice. GRAS Sound & Vibration A/S is not liable or responsible for any errors or inaccuracies that may appear in this document.
Trademarks
Any other product names mentioned in this document may be trademarks or registered trademarks of  their respective companies and are hereby acknowledged.

Introduction

About this Manual
Part 1 describes the items of the configurations. They are ready for use and you will normally not
need to disassemble them. However, if you do, Part 2 describes how they are assembled.
Introduction to 45CA
The GRAS 45CA Hearing-protector Test Fixture is for testing:

• Hearing protection devices such as earmuffs and earplugs
• Sound sources such as headphones (supra-aural, circum-aural) and earphones.
  The test fixture is mounted on a resilient base that reduces the noise floor to a minimum in a typical test situation.
  Foam plugs and grease are used to  avoid sound leakage along the cables.
  The test fixture is delivered in the following configurations:

Testing of Hearing Protectors according to ISO 4869-3
For testing of ear muffs, two configurations are available, either with 1″ or ½″ microphones:
45CA-1 1″ 40EN Externally Polarized Pressure Microphones, conforms with ISO 4869-3.
45CA-2 ½″ 40AD Prepolarized Pressure Microphones, conforms with ISO 4869-3.
Testing of Headphones
For testing of headphones, two configurations with IEC 60318-1 ear simulators are available, either with externally or prepolarized microphones.
45CA-3 RA0039 IEC 60318-1 Ear Simulators, with 40AG Externally Polarized microphones.
45CA-4 RA0039 IEC 60318-1 Ear Simulators RA0039, with 40AO Pre-polarized Microphones.
Testing of Headphones, Earplugs, and Insert Earphones
For testing of headphones and insert earphones, two configurations with pinna simulators and IEC 60318-4 ear simulators are available, either externally polarized or prepolarized.
45CA-5 RA0045 IEC 60318-4 Ear Simulators RA0045, externally polarized.
45CA-6 RA0045-S1 IEC 60318-4 Ear Simulators, prepolarized.
45CA-7 RA0045 IEC 60318-4 Ear Simulators, ext. polarized, with Anthropometric Pinnae.
45CA-8 RA0045-S1 IEC 60318-4 Ear Simulators, prepolarized, with Anthropometric Pinnae.
High-Frequency/Hi-Re Testing
For testing up to 20 kHz, two configurations with High-Frequency Ear Simulators are available, either with externally or prepolarized microphones and anthropometric pinnae.
45CA-9 RA0401 High-Frequency Ear Simulators, with externally polarized microphones.
45CA-10 RA0402 High-Frequency Ear Simulators, with pre-polarized microphones.
For testing up to 50 kHz, two configurations with Hi-Res Ear Simulators are available, either with externally or prepolarized microphones and anthropometric pinnae.
45CA-11 RA0403 Hi-Res Ear Simulators, with externally polarized microphones.
45CA-12 RA0404 Hi-Res Ear Simulators, with pre-polarized microphones.
All configurations are 2-channel.
TEDS Compatibility
Test fixtures with constant-current power (CCP)microphone components (configurations -2, -4, -6, -8, -10, and -12) are IEEE 1451.4 TEDS v. 1.0 compliant. If your measurement platform supports Transducer Electronic Data Sheets (TEDS), you will be able to read and write data like properties and calibration data.
Delivered Items
45CA Headphone/Hearing-protector Test Fixture, Non-configured The components listed below are delivered if you order a 45CA, non-configured. If you order a pre-configured 45CA, the components that comprise the 45CA, non-configured are delivered as
part of the pre-configured assembly.

Included Items

 |

Acoustic Cup

|

1

|

GR0974

| Acoustic Plug| 1| RA0178
|

Foam Plug

|

2

|

GR1281

 |

Sealing Grease

|

1

|

MI0016

 |

Allen Key, 6 mm

|

1

|

YY0019

 |

Allen Key, 2.5 mm

|

1

|

YY0016

 |

Allen Key, 2 mm

|

1

|

YY0018

 |

Allen Key,1.5 mm

|

1

|

YY0012

45CA-1 Headphone/Hearing-protector Test Fixture, ISO 4869-3, 1″ Mic. LEMO
The 45CA-1 is a configuration for testing of outside-the-ear devices, i.e. for measuring the insertion loss of earmuffs and the sound quality of headphones. In this configuration, 45CA is configured with two GRAS 40EN 1″ pressure microphones. 40EN is an IEC 61094 WS1P 1″ externally polarized pressure microphone. This configuration conforms with ISO 4869-3. 45CA-1 is delivered fully configured, individually calibrated and ready for use. The following configuration-specific items are included:

Included Items

| 1² Externally Polarized Pressure Microphone|

2 x 40EN

| 1² to ½² Adapter|

2 x RA0017

| ½² to ¼² Adapter|

2 x RA0003

| ¼² Preamplifier, Short|

2 x 26AS

45CA-2 Headphone/Hearing-protector Test Fixture, ISO 4869-3, ½″ Mic. CCP
The 45CA-2 is a configuration for testing of outside-the-ear devices, i.e. for measuring the insertion loss of earmuffs and the sound quality of headphones. In this configuration, 45CA is configured with two GRAS 40AD ½″ pressure microphones. 40AD is an IEC 61094 WS2P ½″ prepolarized pressure microphone. This configuration conforms with ISO 4869-3. 45CA-2 is delivered fully configured, individually calibrated and ready for use. The following configuration-specific items are included:

Included Items

| ½² Prepolarized Pressure Microphone, High Sensitivity (Used without its protection grid)|

2 x 40AD

| 1² Microphone protection Grid|

2 x RA0177

| ½² to 1² Microphone Adapter|

2 x RA0058

| ½² to ¼² Adapter|

RA0412 (set)

| ¼² CCP Preamplifier with Microdot Connector, Very Short.|

2 x 26CB UN

 |

Microdot to BNC Cable, 3 m

|

2 x AA0070

45CA-3 Headphone/Hearing-protector Test Fixture, IEC 60318-1 LEMO
45CA-3 is configured for measurement of insertion loss of circum-aural hearing protectors and the sound quality of headphones, with two RA0039 Ear Simulators with 40AG ½″ externally polarized microphones. The configuration conforms with IEC 60318-1. The RA0039 cannot be used with a pinna simulator, and therefore cannot be used for measuring in-ear earphones.
45CA-3 is delivered fully configured, individually calibrated and ready for use. The following configuration-specific items are included:

Included Items

|

IEC 60318-1 Ear Simulator

|

2 x RA0039

| ½² Externally Polarized Pressure Micro- phone|

2 x 40AG

| ½² to 1² Adapter for RA0039|

2 x RA0176

| ½² to ¼² Adapter|

2 x GR0010

| ¼² Preamplifier, short|

2 x 26AS

45CA-4 Headphone/Hearing-protector Test Fixture, IEC 60318-1 CCP
The 45CA-4 is configured with two RA0039 Ear Simulators with 40AO ½″ prepolarized microphones. The configuration complies with IEC 60318-1 and is used for measurements of insertion loss of circum-aural hearing protectors and sound quality of headphones. The RA0039 cannot be used with a pinna simulator, and therefore cannot be used for measuring in-ear earphones.
45CA-4 is delivered fully configured, individually calibrated and ready for use.
The following configuration-specific items are included:

Included Items

|

IEC 60318-1 Ear Simulator

|

2 x RA0039

| ½² Prepolarized Pressure Microphone|

2 x 40AO

| Adapter|

2 x RA0176

| ½² to ¼² Adapter|

RA0412 (set)

| ¼² Preamplifier|

2 x 26CB UN

 |

Microdot to BNC Cable, 3 m

|

AA0070

45CA-5 Headphone/Hearing-protector Test Fixture, IEC 60318-4 LEMO
The 45CA-5 is configured with RA0045 externally polarized ear simulators for use with pinna simulators. It can be used for measurements of the insertion loss of ear muffs and ear plugs, and the sound quality of earphones and headphones. The configuration complies with IEC 60318-4. 45CA-5 is delivered fully configured, individually calibrated and ready for use. The following configuration-specific items are included:

Included Items

| Large right and left KEMAR pinna| KB0070 KB0071
| Pinna Holder Plate| 2 x GR1075
| Ear Canal Extension| 2 x GR1069
| IEC 60318-4 Externally Polarized Ear Simulator| 2 x RA0045
| ½² to ¼² Adapter| 2 x GR0010
| ¼² Preamplifier, short| 2 x 26AS

45CA-6 Headphone/Hearing-protector Test Fixture, IEC 60318-4 CCP
The 45CA-6 is configured with RA0045-S1 prepolarized ear simulators for use with pinna simulators. This configuration can be used for measurements of the insertion loss of ear muffs, sound quality of earphones and hearing aids. The configuration complies with IEC 60318-4. 45CA-6 is delivered fully configured, individually calibrated and ready for use. The following configuration- specific items are included:

Included Items

|

Large right and left KEMAR pinna

|

KB0070 KB0071

|

Pinna Holder Plate

|

2 x GR1075

|

Ear Canal Extension

|

2 x GR1069

|

IEC 60318-4 Prepolarized Ear Simulator

|

2 x RA0045-S1

| ½² to ¼² Adapter|

RA0412 (set)

| ¼² Preamplifier, short|

2 x 26CB UN

|

Microdot to BNC Cable, 3 m

|

2 x AA0018

45CA-7 Headphone/Hearing-protector Test Fixture, Anthropometric Pinnae, LEMO
The 45CA-7 is configured with RA0045 externally polarized ear simulators and anthropometric pinna simulators. It can be used for measurements of the insertion loss of ear muffs and ear plugs, and the sound quality of earphones and headphones. The configuration complies with IEC 60318-4. 45CA-7 is delivered fully configured, individually calibrated and ready for use. The following configuration-specific items are included:

Included Items

| Large right and left anthropometric pinnae| KB5010 KB5011
| Pinna Holder Plate| 2 x GR1075
| IEC 60318-4 Prepolarized Ear Simulator| 2 x RA0045-S1
| ½² to ¼² Adapter| RA0412 (set)
| ¼² Preamplifier, short| 2 x 26CB UN
| Microdot to BNC Cable, 3 m| 2 x AA0018
| Exterior Ear Canal (for calibration)| GR0408
| Union Nut (for calibration)| GR0409

45CA-10 Headphone/Hearing-protector Test Fixture, High-Frequency, CCP
The 45CA-10 is configured with RA0402 prepolarized ear simulators and anthropometric pinnae.
This configuration can be used for measurements of the insertion loss of ear muffs, sound quality of earphones and hearing aids. The configuration complies with IEC 60318-4.
45CA-10 is delivered fully configured, individually calibrated and ready for use.
The following configuration-specific items are included:

Included Items

|

Large right and left anthropometric pinnae

|

KB5010 KB5011

|

Pinna Holder Plate

|

2 x GR1075

|

Externally Polarized High-Frequency Ear

Simulator

|

2 x RA0401

| ½² to ¼² Adapter|

2 x GR0010

| ¼² Preamplifier, short|

2 x 26AS

|

Exterior Ear Canal (for calibration)

|

GR0408

|

Union Nut (for calibration)

|

GR0409

45CA-11 Headphone/Hearing-protector Test Fixture, Hi-Res, LEMO
The 45CA-11 is configured with RA0403 externally polarized hi-res ear simulators and anthropometric pinnae. It can be used for measurements of the insertion loss of ear muffs and ear plugs, and the sound quality of earphones and headphones. The configuration is compatible with IEC 60318-4. 45CA-11 is delivered fully configured, individually calibrated and ready for use. The following configuration-specific items are included:

Included Items

| Large right and left anthropometric pinnae| KB5010 KB5011
| Pinna Holder Plate| 2 x GR1075
| IEC 60318-4 Prepolarized Ear Simulator| 2 x RA0045-S1
| ½² to ¼² Adapter| RA0412 (set)
| ¼² Preamplifier, short| 2 x 26CB UN
| Microdot to BNC Cable, 3 m| 2 x AA0018
| Exterior Ear Canal (for calibration)| GR0408
| Union Nut (for calibration)| GR0409

Accessories

Pinnae

Pinna & Ear Simulator Mounting Kit (required to hold a pinna, included in 45CA-5 and -6) Contains a cover plate, ear canal extension, screws and Allen key.| RA0172

KEMAR Large Right Pinna for GRAS 45CA (Included in 45CA-5 and -6)

|

KB0070

KEMAR Large Left Pinna for GRAS 45CA (Included in 45CA-5 and -6)

|

KB0071

KEMAR Small Right Pinna for GRAS 45CA

|

KB0072

KEMAR Small Left Pinna for GRAS 45CA

|

KB0073

KEMAR Large Right Pinna for GRAS 45CA, shore 35

|

KB1070

KEMAR Large Left Pinna for GRAS 45CA shore 35

|

KB1071

KEMAR Right Anthropometric Pinna for GRAS 45CA

|

KB5010

KEMAR Left Anthropometric Pinna for GRAS 45CA

|

KB5011

Power Modules

2-Channel Universal Power Module with signal conditioning and PC interface| 12AQ
2-Channel Power Module with gain, filters and SysCheck generator| 12AA
Calibration Equipment

Intelligent Pistonphone Class 0

|

42AP

Pistonphone Class 1

|

42AA

Multifunction Sound Calibrator

|

42AG

Coupler for 1² microphones (included with 42AP but optional for 42AA)|

RA0023

Calibration Adapter for RA0039 (for 45CA-3 and -4 only)

|

RA0287

½” Calibration Adapter for KEMAR Pinna (For 45CA-5 and -6 only)

|

RA0157

Typical Application Setups

For testing of outside-the-ear devices – the insertion loss of ear muffs and the sound quality of headphones – 45CA-1 (with 1″ microphone) or 45CA-2 (with ½″ microphone) can be used.

For measurement of the sound quality of headphones, 45CA-3 or 45CA-4 can be used. They are configured with RA0039 Ear Simulators and 40AG ½″ externally polarized or 40AO ½″ prepolarized microphones. These configurations comply with IEC 60318-1. Fig. 2. A typical measurements setup for headphone testing. Here shown with externally polarized microphones (45CA-4).
For measurements of the insertion loss of ear muffs and ear plugs, and the sound quality of earphones and headphones, 45CA-5 or 45CA-6 can be used. They are configured with pinna simulators and either externally polarized or prepolarized ear simulators. These configurations comply with IEC 60318-4.

Fig. 3. Typical application setup for testing of earplugs. Here a configuration with externally polarized ear simulators is shown.
Test setups for the configurations 45CA-7 till 45CA-12 are similar to the one shown above.

Mounting the Pinnae

Mounting the Traditional Pinnae
The following pinnae are available for 45CA:

The RA0172 Pinna and Ear Simulator Mounting Kit must be used. This kit is included with 45CA configurations from 45CA-5 to 45CA-10. It comprises a cover plate, four screws, and an ear holder.

1. Make sure that the recess in the pinna locates with the screw in the recess and push it into the recess until it makes full contact with the base of the recess.
2. Make sure that the pinna edge is flush with the surface of the test fixture
3. Mount the cover plate.

Mounting the Anthropometric Pinnae
Two anthropometric pinnae ara avilable:

Fig. 5. Side and front view of a left anthropometric pinna.
Mounting the Anthropometric Pinna:

1. Slacken the screw holding the Ear Simulator, see Fig. 7.

2. Pull out the Ear Simulator.

3. Screw the Pinna onto the Ear Simulator, see Fig. 6
   Fig. 6. The pinna is screw-mounted on the RA0045 Ear Simulator. For clarity, preamplifier and cable are not shown.

4. Push the assembly into 45CA as far as it will go. Ensure that the pinna is tilted correctly (as described in the standard, e.g. the 60318-7), see also Fig. 5, the left part.

5. Tighten the locking screw.

Removing the Anthropometric Pinna
As the Anthropometric Pinna is screw-mounted onto the RA0045 Ear Simulator, this assembly must be removed from the 45CA before the pinna can be separated from the ear simulator.

1. Loosen the screw holding the ear simulator, see Fig. 7 on page 22.
2. Gently pull out the assembly.

Pressure Equalization

45CA is furnished with capillary equalization tubes that connect the cavity under the ear muffs to the external air. When these tubes are not sealed, the pressure build-up that will occur when you fit the ear-muffs will be equalized.
However, before measuring according to ISO4869-3 you may have to close the tubes after having fitted the hearing protector. For this purpose, two 6 mm M3 grub screws are part of the delivery. These are mounted at the bottom of the 45CA test fixture head.

The screws seal after a few turns.

Calibration and Verification

45CA-1 and 45CA-2
Before calibration, the microphone and preamplifier must be removed from the 45CA. To get a good hold on the microphone, cover plate and insert must be removed.
45CA-1 – with 1″ microphone

1. Remove the GR1085 cover plate. Remove the four bolts using the 2 mm Allen key.
2. Remove the GR0970 Insert by loosening the screw at the bottom and pulling it out.
3. Using the 2,5 mm Allen key, loosen the two grub screws at the side of the head.Fig. 10. The microphone can be removed for calibration when the insert and cover plate have been removed. When reinstalled, it must be located precisely as shown,  protruding 1,89 mm at the horizontal center line.
4. Pull out the microphone.
   You are now ready to calibrate. The GRAS RA0023 Coupler for 1″ microphones must be used, it is included with the 42AP and an optional accessory for 42AA.
   The correction factor is 0.0 dB, and therefore you analyzer should read 114 dB +/- correction for the static ambient pressure. Refer to your pistonphone manual for detailed calibration instructions.

Reinstalling the Microphones
When calibration has been completed, you must reinstall the microphones in the test fixture.
This is done reversing the steps on the previous page.
When installed correctly, the microphones (with protection grid) must protrude 1.89 mm at the horizontal center line as shown in Fig. 10 on page 24. This will ensure that the microphone diaphragm is flush with the surface of the 45CA at the horizontal center line, as defined in ISO 4869-3.
45CA-2 – with ½″ Microphones
When mounted in the ½″ to 1″ Adapter, the ½″ microphones can be calibrated the same way as the 1″ microphones. Microphone and adapter can be removed as described on page 17.
Place the microphone with its adapter in the pistonphone collar.
The correction factor is 0.0 dB, and therefore you analyzer should read 114 dB +/- correction for the static ambient pressure.
Refer to your pistonphone manual for detailed calibration instructions.
45CA-3 and 45CA-4
45CA-3 and 45CA-4 can be calibrated in-situ without dismantling couplers and microphones.
However, the accuracy that can be obtained is no better than ±0.3 dB, so this would rather be a verification. A proper calibration requires that the microphone is dismantled and calibrated separately.
Verification
The 45CA-3 and 45CA-4 can be verified in-situ using the Calibration Adapter RA0287.

1. Loosen the Pistonphone’s collar and mount the verification adapter.
2. Place the pistonphone onto the ear simulator.
3. Hold the Pistonphone strictly horizontally. An accuracy of ± 0.3 dB can be obtained.
   Refer to your pistonphone manual for further instructions.

Calibration of 45CA-3 and 45CA-4
To perform a proper calibration, you must dismount the ear simulator from the test fixture.

1. Release the two grub screws on the side of the test fixture, see Fig. 7 on page 22. The screw must be loosened to fully release its pressure on the ear simulator. Removing the cover plate will make removal of the ear simulator easier.
2. Remove the ear simulator unit.
3. Unscrew the microphone from the ear simulator unit.
4. Insert the microphone in the pistonphone.
   See your pistonphone manual for further instructions.
   The correction factor is 0.0 dB (42AP and 42AA), and therefore you analyzer should read 114 dB +/- correction for the static ambient pressure. Refer to your pistonphone manual for detailed calibration instructions. When calibration has been done, install the microphone in the coupler and the coupler in the test fixture by reversing this procedure.

45CA-5 and 45CA-6
The RA0045/RA0045-S1 Ear Simulators can be calibrated in-situ once the pinna has been removed.

1. Remove the pinna.
2.  Mount the RA0157 Calibration adapter on the pistonphone.
   Hold the pistonphone strictly horizontally.
   The correction factor is -0.62 dB, and therefore your analyzer should read 114 dB minus 0.62dB at 250 Hz and correction for the static ambient pressure. Refer to your pistonphone manual for detailed calibration instructions.

46BP-1 45CA-7 to -12
As described on page 22 the anthropometric pinna is mounted directly on the Ear Simulator, without the use of en ear canal extension. Therefore, for calibration with a pistonphone with a ½″ coupler, the ear simulator and the anthropometric pinna must be removed to allow mounting of the GR0408 External Ear Canal.
Removing the Ear Simulator and Anthropometric Pinna

1. Loosen the screw holding the ear simulator, see Fig. 7 on page 22.

2. Gently pull out the assembly. See also Fig. 8 on page 23.
   Important. Do NOT pull at the ear lobe.

3. Unscrew the pinna simulator from the ear simulator

4. Mount the external ear canal with the union nut onto the ear simulator.
   You are now ready to calibrate. The Ear Simulator fits directly into a pistonphone with a ½″ coupler. Refer to your pistonphone manual for further information. See the corrections factors in the table below.

Correction Factors
The correction factors for the various calibration options are listed below. The correction factors are needed because the different calibration options introduce varying effective volumes.
The correction factors have nothing to do with the different pinna used.

45CA-1 to -12 with Standard Ear Simulator (RA0045-series and RA040X-series)

In-situ calibration, without dismantling

 | Accessories| Correction factor
42AP and 42AA| RA0157| -0.62 dB
The cover plate and ear simulator removed
42AP and 42AA| GR0408| -1.03 dB
42AG @250 Hz, 114 dB| GR0408| -0.09 dB
42AG @250 Hz, 94 dB| GR0408| -0.09 dB
42AG @1KHz, 114 dB| GR0408| -0.2 dB
42AG @1KHz, 114 dB| GR0408| -0.2 dB

Technical Specifications

45CA
45CA is built in accordance with ISO 4869-3.

45CA-1 and 45CA-2

Self Insertion Loss, measured with closed ear simulators

80 – 250 Hz

|

50dB

350- 4000 Hz

|

65dB

5000- 20000 Hz

|

55dB

45CA-3 and 45CA-4

RA0039 Ear Simulator

Standards
IEC 60318-1| Ear simulator for the calibration of supra-aural and circumaural earphones

ITU-T Recommendation P.57

| Series P: Telephone transmission quality, Objective measuring apparatus: Artificial ears
Frequency Response
Typical frequency response|
Sensitivity
Sensitivity| 12.5 mV/Pa
Dynamic Range
with 40AG| 20 dBA to 164 dB
with 40AO| 20 dBA to 163 dB
Dimensions
Height| 19.8.0 mm
Diameter| 60 mm
Environmental Calibration Conditions
Temperature| 23 °C ±3 °C
Relative humidity| 60 % ±20 %
Barometric pressure| 101.3 kPa ±3 kPa

45CA-5 to 45CA-8

RA0045/RA0045-S1 Ear Simulator

Standards
IEC 60318-4| Occluded-ear simulators for the measurement of earphones coupled to the ear by

ear inserts

ITU-T Recommendation P.57| Series P: Telephone transmission quality, Objective measuring apparatus: Artificial ears
ANSI S3.25/ASA-2009| American National Standard For an Occluded Ear Simulator
Frequency Response
Typical transfer impedance re 500 Hz|
Resonance frequency| 13.5 kHz ± 1 kHz
Sensitivity
Sensitivity| 12.5 mV/Pa
Dynamic Range|
RA0045 (LEMO)| 25 dBA to 164 dB
RA0045-S1 (CCP)| 25 dBA to 153 dB
Effective Volume
at 500 Hz| 1260 mm3
Dimensions
Height| 23.0 mm
Diameter| 23.75 mm

45CA-9 and 45CA-10

RA0401/0402 High-Frequency Ear Simulator

Standards
IEC 60318-4| Occluded-ear simulators for the measurement of earphones coupled to the ear by

ear inserts

ITU-T Recommendation P.57| Series P: Telephone transmission quality, Objective measuring apparatus: Artificial ears
ANSI S3.25/ASA-2009| American National Standard For an Occluded Ear Simulator
Frequency Response
Typical transfer impedance re 500 Hz|
Resonance frequency| 13.5 kHz ± 1 kHz
Sensitivity
Sensitivity| 12.5 mV/Pa
Dynamic Range|
RA0401 (LEMO)| 25 dBA to 164 dB
RA0402 (CCP)| 25 dBA to 153 dB
Effective Volume
at 500 Hz| 1260 mm3
Dimensions
Height| 23.0 mm
Diameter| 23.75 mm

45CA-11 and 45CA-12

RA0403/RA0404 Hi-Res Ear Simulator

Standards, based on:
IEC 60318-4 (compatible)| Occluded-ear simulators for the measurement of earphones coupled to the ear by

ear inserts.

ITU-T Recommendation P.57| Series P: Telephone transmission quality, Objective measuring apparatus: Artificial ears
ANSI S3.25/ASA-2009| American National Standard For an Occluded Ear Simulator
Frequency Response
Typical transfer impedance re 500 Hz|
Resonance frequency| 13.5 kHz ± 1 kHz
Sensitivity
Sensitivity| 1.6 mV/Pa
Dynamic Range|
RA0403 (LEMO)| 44 dBA to 169 dB
RA0404 (CCP)| 46 dBA to 174 dB
Effective Volume
at 500 Hz| 1260 mm3
Dimensions
Height| 23.0 mm
Diameter| 23.75 mm

Warranty, Service and Repair

Calibration
Before leaving the factory, all GRAS products are calibrated in a controlled laboratory environment using traceable calibration equipment.
We recommend a yearly recalibration at minimum, depending on the use, measurement environment, and internal quality control programs.
Warranty
Damaged ear simulators can be replaced or repaired. The microphone diaphragm, body, and protection grid are made of high-grade stainless steel, which makes the microphone resistant to physical damage, as well as corrosion caused by aggressive air or gasses. This, combined with the reinforced gold-plated microphone terminal which guarantees a highly reliable connection, enables GRAS to offer 5 years warranty against defective materials and workmanship. The warranty does not cover products that are damaged due to negligent use, an incorrect power supply, or an incorrect connection to the equipment.
Service and Repairs
All repairs are made at GRAS International Support Center located in Denmark. Our Support Center is equipped with the newest test equipment and staffed with dedicated and highly skilled engineers. Upon request, we make cost estimates based on fixed repair categories. If a product covered by warranty is sent for service, it is repaired free of charge, unless the damage is the result of negligent use or other violations of the warranty. All repairs are delivered with a service report, as well as an updated calibration chart.

Manufactured to conform with:

GRAS Sound & Vibration continually strives to improve the quality of our products for our customers; therefore, the specifications and accessories are subject to change.
Instruction Manual
GRAS 45CA Headphone/Hearing-protector Test Fixture

References

• GRAS Sound and Vibration

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