True automotive multifield high-sensitivity microphone released

GRAS Sound and Vibration, part of Axiometrix Solutions, has released a new measurement microphone ideal for automotive in-cabin and NVH testing.

The new GRAS 46BC CCP ¼″ Multifield Microphone Set, High Sensitivity, is a microphone offering a particular set of skills. Targeting automotive acoustic assessments (from in-cabin speech transmission index to EV inverter switching frequency noise), the microphone is created with all the advantages of small microphones. It also profits from the low-noise capabilities of its considerably larger ones ½″ cousins.

The primary reason that ¼″ microphones had not been used for in-cabin measurements was the noise floor. It was far higher and would miss noise contributors such as road and brake noise or even the higher frequency contributions that could not be measured by a microphone with a 40dB(A) noise floor. The high-sensitivity 46BC eliminates this issue. With a noise floor of 24dB(A), it outperforms all other ¼″ microphones and removes the need for using a variety of ½″ microphones to only come close to the same data quality.

The microphone's effect on the environment is decreased, and the impact of the angle of incidence from the sound source is minimal. These are challenges for ½″ microphones. They have significant pressure build-ups in front of the diaphragm, which causes further challenges in a mix of pressure- and free-field environments and can deliver under-represented data as the angle of incidence increases. The device gains from the unique tuning of its response curve to be a truly multifield microphone.

The blend of small-size benefits, multifield tuning, and the lower noise floor of the new device supplies a microphone that is the best of two worlds for automotive acoustic testing.

"There is a general trend in measurement to take advantage of ¼″ microphone capabilities, but their noise floors meant they could miss some potentially irritating noise contributions. Developing a ¼″ microphone with a 24dB(A) noise floor opens up a new range of measurement capabilities resulting in a better product for end users," Dr Rémi Guastavino, director of Product Management.