The G.R.A.S. 45CB Acoustic Test Fixture is designed and specified to comply with the ANSI/ASA S12.42 standard. With this test fixture, you can test all types of hearing-protectors in the most realistic way – both in the acoustic lab and in the field.
Compliance with ANSI/ASA S12.42 assures technicians, decision makers, and authorities of repeatable and transparent data when developing and verifying hearing protectors.
The 45CB’s robust design is ideally suited for binaural testing of active and passive earplugs, as well as circumaural hearing protectors. It is designed for portability, which gives you flexibility for your testing setups.
The 45CB directly handles sound pressure levels up to 170 dB and, indirectly (using compasion methods), levels up to 190 dB. The 45CB has a self insertion-loss better than 65 dB, which means you are actually measuring the insertion loss of your hearing protector and not the fixture.
The modified IEC 60318-4 ear simulator (711) with a ¼” microphone extends the frequency range required by the standard (from 80 Hz all the way up to 20 kHz). The 14-mm long ear canal extension is designed to let you also test all types of ear plugs. The silicone-rubber lining of the extension enables leakage-free mounting of both foam plugs and customized molded types.
Another design advantage is the large base plates of the pinna simulators. They can accommodate all types of circumaural ear muffs. The silicone-rubber lining of the plates ensures leakage-free mounting, as well as higher repeatability and reliability.
All the silicone-rubber parts of the 45CB can be heated to body temperature to give the most realistic testing of in-situ performance of ear-plugs. The heating unit of the system is set by default to 37 degrees Celsius.
Calibration is easy with the 45CB. You only need a pistonphone to quickly verify the full measurement chain within minutes and not waste valuable time and resources on a non-calibrated setup.