Automotive noise, vibration, and harshness (NVH) measurement spans the full vehicle development cycle — from component-level source characterisation in semi-anechoic chambers to full-vehicle certification pass-by noise testing on outdoor tracks. With the rapid transition to electric powertrains, the acoustic challenges of automotive development have shifted: tonal motor whine and inverter harmonics have replaced combustion noise as the primary interior sound quality challenge, while tire-road and aerodynamic noise now dominate at higher speeds without combustion masking.
Pass-by noise certification to ISO 362 and UN Regulation 51 requires Class 1 measurement microphones at specified positions relative to the track, connected to calibrated data acquisition systems that can capture the full pass-by event. Interior noise measurements use arrays of microphones placed at defined head positions to characterise the acoustic environment at each seat position. Transfer path analysis (TPA) and sound source identification use beamforming arrays and simultaneously sampled multi-channel DAQ.
The EU Regulation 540/2014 requires all new electric and hybrid vehicles to be equipped with an AVAS (Acoustic Vehicle Alerting System) emitting sound at low speeds to alert pedestrians. AVAS sound design, verification, and certification testing requires measurement microphones with flat frequency response across the AVAS operating band, calibrated signal conditioning, and software capable of octave band and 1/3 octave band analysis.
Pass-by noise certification to ISO 362 requires careful calibration management. The microphone calibration certificate must be valid at the time of the test, and the calibrator check records must be preserved as part of the type approval documentation. PLACID ISO/IEC 17025 accredited calibration certificates meet the requirements of type approval testing authorities, and can be issued with accreditation scope documentation on request.