GRAS RA0045 Externally Polarized Ear Simulator According to IEC 60318-4 (60711)

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The IEC 60318-4 ear simulator is widely applied in verfication of frequency response of acoustic products, e.g. in the consumer audio industry, but also for measurements on hearing aids. It is recognized for its ability to simulate the acoustic load as presented by the ear. Placing a headphone on a standardized ear simulator, e.g. a GRAS RA0045 Ear Simulator ensures that the headphone is facing the same acoustic input impedance as a real human ear would provide.

An ear simulator based on the standard IEC 60318-4 is therefore necessary to obtain a realistic acoustic transmission line from the output of the transducer (e.g headphone or a hearing aid) placed in a known measurement plane (eg. the ear entrance point) to the ear drum point in the ear simulator. However, the tradicional IEC 60318-4 (GRAS RA0045) ear simulator has an undamped length resonance at 13.5 kHz that makes it difficult to use for high-frequency testing.Therefore, GRAS has introduced two improved variants of the IEC 60318-4 ear simulator. They retain a firm footing in the standard but improve the ability to measure at high frequencies. Discover the evolution of the IEC 60318-4 ear simulators here.

 

The Standard IEC 60318-4 (711) Ear Simulator (GRAS RA0045)

It has a step half-wave resonance at 13.5 kHz which effectively limits its usefulness to below at least 10 kHz. It uses a ½" microphone.
Learn more

Ear RA040X

The High-Frequency Ear Simulator (GRAS RA0401/02)

It has a dampings system that attenuates the half-wave resonance at 13.5 kHz and thus extends the useful frequency range to 20 kHz. It uses a ½" microphone. Learn more

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The Hi-Res Ear Simulator (GRAS RA0403/04)

It also has a damping system that attenuates the length-related resonances above 10 kHz, but the use of a ¼” microphone extends the useful frequency range to 50 kHz and beyond. Learn more

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The Broadest Range of Ear Simulators

GRAS offers the industry’s broadest range of ear simulators and couplers: A full range of IEC 60318-1 to 5 ear simulators, complemented by a number of improved versions of the standardized IEC 60318-4 ear simulator. This range of ear simulators comprises:

> The standardized IEC 60318-4 ear simulator
> A low-noise version for measurements down to 10.5 dB
> A high-frequency version for measurements up to 20 kHz
> A Hi-Res version for measurements up to 50 kHz

Whether your need is IEC-standardized testing, improved standardized testing with anthropometric pinnae or testing up to 20 kHz or even 50 kHz, we have preconfigured ready-to-use solutions. 

LEARN ABOUT OUR TEST SOLUTIONS

If you need an even more highly specialized test set-up tailored to your specific needs, we can help you with a customized solutioncontact your local GRAS partner for further information. 

Volume: 1260 mm³ @ 500 Hz
Dyn range: 25 dB(A) to 164 dB
IEC: 60318-4

GRAS RA0045 Externally Polarized Ear Simulator According to IEC 60318-4 (60711)

Technology

Introduction

The RA0045 Ear Simulator is for making acoustic measurements on earphones coupled to the human ear by ear inserts such as tubes, ear moulds, or ear tips. The acoustic input impedance of RA0045 closely resembles that of the human ear and, as a result, loads a sound source in very much the same way.

The RA0045 complies with the following international requirements:

  • IEC 60318-4: Occluded-ear simulator for the measurement of earphones coupled to the ear by ear inserts.
  • ITU-T Recommendations P.57 (08/96) Series P: Telephone transmission quality, Objective measuringapparatus: Artificial ears.

It is measured and calibrated according to the ITU-T Recommendation P.57.

Design

The RA0045 embodies a number of carefully designed volumes connected via well-defined and precisely tuned resistive grooves. In an equivalent electrical circuit, capacitors would represent the volumes, and inductance and resistance would represent respectively air mass and air flow within the resistive groves.

It is delivered with a built-in GRAS 40AG 1/2" externally polarized pressure microphone and an individual calibration chart for the ear simulator.

Typical Applications and Use

The RA0045 is for measurements on earphones and hearing aids coupled to the human ear by ear inserts such as tubes, ear moulds, or ear tips.

In accordance with ITU-T Recommendation P.57, it can be used with the following GRAS pinna simulators for testing telephones:

It is also part of the GRAS 43AC Artificial Ear which is a complete test jig for acoustic testing of earphones coupled to the ear by inserts.

A comprehensive range of accessories for making measurements in accordance with IEC 60318-4 are available. See the tab Ordering info.

Compatibility

The RA0045 can be used with a standard LEMO preamplifier, e.g. the GRAS 26AK 1/2" Preamplifier or the GRAS 26AC 1/4" Preamplifier fitted with an adapter. For the 1/4" preamplifier, use either the straight RA0003 Adapter or the right-angled RA0001 Adapter.

Specifications

Polarization/Connection
200 V / Traditional
Theoretical dynamic range lower limit with GRAS preamplifier
dB(A)
25
Theoretical dynamic range upper limit with GRAS preamplifier @ +28 V / ±14 V power supply
dB
153
Theoretical dynamic range upper limit with GRAS preamplifier @ +120 V / ±60 V power supply
dB
164
Resonance frequency
kHz
13.5
Coupler volume
mm³
1260 @ 500 Hz
Temperature range, operation
°C / °F
-30 to 60 / -22 to 140
Temperature coefficient @250 Hz
dB/°C / dB/°F
0.05
Humidity range non condensing
% RH
0 to 75
ANSI standard
S3.7
IEC standard
60318-4 (former 60711)
ITU-T recommondations
P.57
CE/RoHS compliant/WEEE registered
Yes/Yes,Yes
Weight
g / oz
52 / 1.8


Typical frequency response

GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

Dimensions

Ordering info

 Optional items

GRAS RA0088

In Ear Adapter

GRAS GR0433

Calibration Adapter

GRAS GR0434

Stop Washer

GRAS GR0436

Tube Adapter

GRAS GR0437

Ear-mould Simulator

GRAS GR0438

Retention Ring

GRAS GR0440

Tube Adapter

GRAS RA0056

Low-leak Pinna Simulator

GRAS RA0057

High-leak Pinna Simulator

GRAS 26AK

26AK 1/2'' Standard Preamplifier with Integrated Connector

GRAS 26AC

26AC 1/4" Standard Preamplifier with 3 m Integrated Cable

GRAS RA0001

Right-angled Adapter for 1/2" microphone and 1/4" preamplifier

GRAS RA0003

Adapter for 1/2" microphone and 1/4" preamplifier

GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.

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