Automotive acoustic standards are evolving: The tools must pave the way

One microphone to meet all the needs of in-cabin measurement—GRAS Multifield ¼″ Low-noise Microphone.

Constant improvements in vehicles are pushing boundaries with better audio systems and noise mitigaton solutions, and customers have even higher expectations for EVs that push testing even farther. Testing needs have passed beyond the capability of traditional ½″ microphones.


Valid data in any sound field

The size and design of the 46BC multifield microphone provides the right data in any measurement scenario and will always comply with IEC 61672, regardless of the sound field.

The lowest noise floor

GRAS 46BC has the lowest noise floor of any ¼″ microphone, so it matchs the sensitivity of ½″ mics and can therefore measure the low levels found in a car cabin.

Evolving for EV testing

The high sensitivity and low noise floor coupled with the size advantages of the 46BC provide the ideal solution for aquiring in-cabin data for both audio and NVH testing.

GRAS 46BC CCP Multifield ¼″ Microphone Set, High Sensitivity: The only high-sensitivity multifield microphone on the market

New challenges arise as vehicle occupants experience quieter engines and motors, more sophisticated dampening, and interact more and more with the vehicle through voiced commands and responses. The unique combination of small size and extremely low noise floor, extends measurement accuracy, particularly in the high-frequency range.

In cabin

ICE or EV, the need for cabin comfort and clear communication is paramount. In fact, in-cabin sound quality is frequently cited as a key aspect of how customers evaluate vehicles and is influenced by all potential sound sources and treatments in a vehicle: from sound transmission from transmissions, engines and motors. and wind, tire, and brake noise to the wrong frequencies being dampened or accentuated by reflective or difuse materials.

The in-cabin sound field consists of a mix of varried damping surfaces and hard reflective surfaces, so the sound field varries from free field to random incidence (or undefined). This is a challenge for traditional ½″ microphones; however, this is perfect for a ¼″ microphone designed for multifield environments.


Audio assessments are a vital part of new vehicle development. Consumers expect high-quality sound systems, so the importance of ensuring good acoustics, free from reverberation and excess dampening in desired frequency ranges, is greater than ever. Add to that, the development of systems requiring improved communication with infotainment systems and artificial intelligence assistance while driving has evolved to unprecedented heights.

Assessing audio quality in environgments as complex as the cabin of a vecle is a difficult task. However, the multifield capabilities of 46BC combined with the measurement accuracy (particularly at higher frequencies) make it ideal for the job. Additionally 46BC and the 46BL-1 pressure microphone, are idealy suited for measurements according to the AES In-car Acoustics Measurements recommendation.

Electric Vehicles

New EV models are being introduced with much greater frequency, and while market competition increases, the transition away from ICEs has introduced a new range of challenges inside the cabin.

The loss of engine and transmission masking noise means that there are suddenly old but unheard noises that need to be addressed. But also the new electric motor introduces new noises of its own, such as the highfrequency tonal noise from the inverter. This noise is prominent over 5 kHz where it stands out over wind and tire noise. This high-frequency noise has a strong negative impact on occupants’ perception of overall sound quality. The improved accuracy of the 46BC in the higher frequency ranges and its ability to provide precise data regardless of th angle of incidence makes the 46BC the perfect microphone for EV audio and NVH testing.

Computer Modeling

The ever-developing capabilities in computer-aided engineering have a huge impact on the design phase of new vehicles.

The key factor in developing an accurate model, is accurate data. The combination of hard reflective surfaces and the transition to lighter interior materials with less dampening creates a highly complex environment. Microphones used to acquire data for initial input and later validation for models must be able to acquire accurate data in a varied environment.

The solution is a small, high-sensitivity multifield microphone with a very low noise floor and superior accuracy, particularly at higher frequencies, such as GRAS 46BC.

The automotive industry has always been in a constant state of development and progress, and that state is accerating faster than ever with the transition to EV technology and concepts.

Test and measurement tools and technology must not only meet the current needs of the industry, they must stay ahead of the curve. To find out how GRAS 46BC and 46BL-1 can help you get the data you need today and tomorrow, complet the Contact form below or visit us at or


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