In-Car Audio Measurements
A test sequence to measure the impulsive distortion, frequency response, and maximum sound pressure level of a vehicle
This sequence makes in-car audio measurements of the transient distortion (also known as buzz, squeak, and rattle, Rub & Buzz, or impulsive distortion), frequency response, and maximum sound pressure level of a vehicle infotainment system to the methods outlined in the Audio Engineering Society Technical Committee on Automotive Audio (TC-AA) in-vehicle measurements white paper (draft). This white paper aims to define repeatable and defined car audio system measurements and in addition to the measurement methods, contains information on standardized test configuration, for example microphone and seat positioning. Please contact the TC-AA for more information on this project. This test sequence may, of course, be used with your own in-house physical configuration if adherence to the TC-AA guidelines is not essential.
This sequence includes one master sequence, three subsequences, plus a level check subsequence for calibration. The three individual subsequence tests have also been included in a separate folder so they may be run standalone. The standalone sequences each have their own Bluetooth connect and disconnect steps.
Required Equipment for In-car Audio Measurements
- SoundCheck Plus Version 20 or later Part #1102
- RTA Analyzer Part #2005
- 8 channel acquisition module Part #2024
- Interface with 6 inputs – Listen AmpConnect 621 or similar Part #4046
- Bluetooth interface – Portland Tool & Die BTC/BQC or similar Part #5816
- 6 SCM Microphones with holder* or similar. Part #4012
Setup Diagram for In-Car Audio Measurements
Hardware Setup and Calibration
- Connect the microphones to input 1-6 of your audio interface.
- Calibrate the microphones as instructed in the SoundCheck manual.
- Place the six microphones in the vehicle, adhering to the microphone array and positioning appendix section in the white paper.
- All accessible audio system settings should be set to default or factory reset to neutral or flat. These settings should be documented.
Learn more about connecting to car audio.