GRAS RA0045 Externally Polarized Ear Simulator According to IEC 60318-4 (60711)
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
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
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
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 solution – contact your local GRAS partner for further information.
Volume: 1260 mm³ @ 500 Hz
Dyn range: 25 dB(A) to 164 dB
Sensitivity 12.5 mV/Pa
IEC: 60318-4
The GRAS RA0045 is an ear simulator with an acoustic input impedance closely resembling that of an average human ear. It includes a 40AG pressure microphone and is individually calibrated with this specific microphone.
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:
- GRAS RA0056 Low-leak Pinna Simulator
- GRAS RA0057 High-leak Pinna Simulator
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
Typical frequency response
GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.
Dimensions
Ordering info
Optional items
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 |
Low-leak Pinna Simulator | |
High-leak Pinna Simulator | |
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 RA0525 | Foam insert for 60318-4 coupler, 10 pcs |
GRAS RA0003 | Adapter for 1/2" microphone and 1/4" preamplifier |
GRAS Sound & Vibration reserves the right to change specifications and accessories without notice.
