Standardization of the GRAS RA0252 Coupler

New IEC standard for acoustic 0.4cc couplers, enables GRAS to offer a cost-efficient validation tool in the frequency range up to 16 kHz that adheres to standards.

GRAS Sound & Vibration, part of Axiometrix Solutions, a global leader in test and measurement solutions, has a complete line of production line tools for high-frequency measurements and is now the only provider of 0.4cc couplers that follow IEC standards.

The latest IEC standard 60318-8:2022 describes an acoustic coupler for loading a hearing aid or insert earphone with a specified acoustic impedance when testing its acoustic performance, in the frequency range up to 16 kHz.

GRAS has a strong portfolio of acoustic couplers and ear simulators, and the RA0252 coupler as well as the GRAS 43BA with a ¼” microphone and preamplifier, have been available for quite some time. However, with the latest standard, hearing aid manufacturers can now be confident that also when testing in the 8-16 kHz frequency range, they are able to follow the requirements in a production line setup.

This marks another important step in our effort to be able to offer our hearing aid customers cost-efficient measurement solutions that create confidence along the entire measurement chain”, says Brian Johansen, Senior Acoustic Engineer at GRAS Sound & Vibration.

The 43BA is available in both a LEMO version, a CCP version as well as a high sensitivity CCP version. Both the RA0252 and the 43BA are compatible with existing 2cc couplers, including custom-built fitting adaptors.


For further information, please contact:
Martin M. Khan
Global Marketing Director Phone: +45 5157 3095
or write to
Download here the press release.

GRAS is a worldwide leader in the sound and vibration industry. We develop and manufacture state-of-the-art measurement microphones and related equipment for industries where acoustic measuring accuracy and repeatability are of the utmost importance. This includes applications and solutions for customers within the fields of aerospace, automotive, audiology, consumer electronics and other highly demanding industries. GRAS microphones are designed to live up to the high quality, durability and accuracy that our customers have come to expect, trust and require.

GRAS Sound & Vibration is represented through subsidiaries and distributors in more than 40 countries and is part of Axiometrix Solutions, a leading test solutions provider comprised of globally recognized measurement brands, including Audio Precision and imc test and measurement.