Methods of Acoustical End-of-line Testing for Sound Quality Assurance during Vehicle Manufacturing

The standard approach for identifying disturbing noise sources inside a vehicle is a test drive, whereby the driver decides whether the car is OK or not. However, this approach has several disadvantages: the subjectivity of the test driver, the long time and test track necessary, the risk of car damage and the very high costs entailed. We'll present various approaches and technologies for the investigation of acoustical issues during end-of-line testing: fully- and semi-automated. One approach is to utilize a nozzle gate that moves over the car to be tested, blowing air onto the car in order to simulate the airstream during a drive. The gate stops at critical points, where the acoustical measurement system records the acoustical spectrum from each microphone inside the car and compares this with a reference spectrum. Another method is to use a similar measurement system in a wind-tunnel, whereby further parameters, e.g. different blowing angles, can be applied. A third method is the utilization of a handheld acoustical camera in combination with a sound source. We present a process utilizing a combination of these methods in order to detect, localize and solve acoustic issues in a vehicle during an end-test.