Leakage ranking of vehicle cabin interiors is an important quality index for a car. Noise transmission through weak areas has an important role in the interior noise of a car.
Nowadays the acoustic leakage inside a cabin can be measured with different techniques: Microphone array-based holography, Trasmission loss measurement, Beamforming analysis, Sound intensity P-P measurements and ultrasound waves measurements. Some advantages and limits of those measurement approaches for quantifying the acoustic performance of a car are discussed in the first part of this paper.
In the second part a new method for fast leakage detection and stationary noise mapping is presented using the Microflown PU probe. This method is called Scan & Paint. The Microflown sensor can measure directly the particle velocity which in the near field is much less affected by background noise and reflection compared with normal microphones. This makes the sensor very suitable for measurements inside a complex and reactive environment like the interior of the car.
A camera is used to film the sweep measurement procedure of some surfaces in the cabin interior of a Toyota Avensis. The audio data is processed and synchronized with the video data. A velocity or intensity colormap can be calculated for the different interior parts of the car under test.