Phenomenas such as rattling, hissing, or clicking noises are undesired in any vehicle. Even at high speed, the pianissimo parts of classic music should not be drowned out by driving noise. The Acoustic Camera has therefore been in use since long and with great success in the automotive industry.
Shutting the door, however, must produce a full sound despite the lightweight construction. There are similar requirements for the sound of car engines. The roar of a sports car or the sonorous sound of a Sedan are typical distinctive characteristics of car brands. That's why big effort goes into modelling the desired sound and into eliminating disturbances.
Sound issues are playing an increasingly important role in household appliances. Some high-value products can already be identified by their "high-value sound". Noises that are usually associated with faults like clicking, crackling, or whistling can annoy customers and frequently lead to unnecessary complaints.
The time, frequency and modal analyses used so far have a decisive disadvantage: the spatial resolution is limited or non-existent. To record many spots and positions of the machine at the same time, a separate microphone for each is necessary for measurement point, which has to be placed close to the measurement object - a high financial and time expenditure.