An Engineering Approach to Sound Quality

The subjective quality of sounds is a topic of increasing importance in the automotive industry. The first consideration is to describe the perceptual characteristics of this quality by means of jury tests or appropriate metrics.

Once a NVH problem is determined in terms of an appropriate Sound Quality description, an in-depth analysis of the underlying physical phenomena must be made and engineering solutions newel to be proposed and validated

This involves:

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  the detailed analysis of the signal structure in the time, frequency and order domain and identifying the signal Components Critical to the relevant sound quality dimension
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  the Correlation of the critical signal components to specific sources noise or vibration transmission paths and vibro-acoustic system characteristics.

Ultimately this should lead to the prediction of the effect of feasible modifications in sound quality terms through the use of engineering models. This is up to now however only possible for a limited set of NVH problems due to limitations of Current modelling methods.

The above procedure will be reviewed for a typical selection of sound quality cases.

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  a road noise problem (broad-band signal)
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  the sound of a door-slam (transient signal)

Finally an overview of present research on the level of modelling for sound quality will be given; and the Collaborative EC project “SOQCRATES” on automotive sound quality engineering will be presented