Volkswagen Caddy diesel
With the Sorama Scan M or A it is easy to make a sound image of Volkswagen Caddy diesel. It shows, among other effects, low-frequency engine noise at high spatial resolution and noise leakage through door seals. A small selection of these results are shown in the movie to the right. What strikes is the spatial detail of a few centimeters at a frequency of 29Hz, where the acoustic wave-length is about 12 meters.
Without the (masking) noise of a combustion engine other irritating noise sources start to dominate. From the Sound Imaging pictures two components become apparent: the electrical driver of the led lighting (left) and the water pump (right). A further analysis that can zoom-in on these two components makes it possible to come up with ways to best eliminate these noise sources.
For DTI, Sorama analyzed a strange whistle noise in a newly developed gearbox. The spectral analysis in combination with the sound Imaging results shows that the tooth passing frequency under load was causing the high whistle. By shifting to helical gears this problem was tackled in a redesign process.
MERCEDES-BENZ - FIRETRUCK
Sorama was asked to analyze the emitted sound from fire truck during high pressure pump use. By using a line array. the complete truck was imaged and the results showed two major noise sources. The Gearbox PTO and the high pressure pump were clearly visible in the sound images. By decoupling different panels and screening the pump and PTO modules, large improvements could be made.