One definition of Sound Quality has been given by Blauert:

Sound Quality is the suitability of a sound for a specific technical task.

The task can be to inform the user what type of product it is, what it is doing and how it is doing.

For this sound the information is “sporty car”, “accelerating”, and e.g. “powerful, dynamically”. While this sound shows a good Sound Quality for this product type (sportscar), it would be unsuitable for a related product type like a limousine. 

Sound Quality is product specific!

Reasons for a poor Sound Quality can be grouped as follows:

  • defects of the product (more a product quality problem than a Sound Quality porblem)
  • disturbing sound features
  • reduction of the overall sound level resulting in a reduction of masking. Sound components which have been masked before now can get audible!
  • poor overall sound impression
  • unsuitable information delivery (the “task” is not fulfilled)

Since Sound Quality is product specific, also the approach to measure and improve Sound Quality has to be product specific. The following general procedure is appropriate:

  1. Determination of the product-specific quality requirements (task of the sound, target group, critical/representatibe operation condition, acoustical, non-acoustical and cognitive moderating factors, ...)
  2. Signal measurement (if appropriate considering also products from concurrent manufacturers)
  3. Psychophysical investigation of the current status
  4. Signal analysis
  5. Identification of characteristic and percetually relevant sound features by means of comparison of psychophysical investigation and signal analysis. The dimensions or characteristics whích have a positive or negative influence on Sound Quality are determined.
  6. Improvement of the sound by means of varying the identified parameters.

The last step can often efficiently be performed by simulation (e.g., sound filtering or synthesis), so that no prototypes have to be build during sound optimization.