Richard G. Cann
RH Lyon Corp, Cambridge, MA 02138
The quality of a sound that a product makes is used by the listener in many ways. Broadly, the listener judges from the sound quality the identification of the type of the source. Once identified, the information contained in the sound may be used further. It may be used for practical diagnostic purposes, such as identifying an unanticipated fault or a mode of operation. It may also be used on an aesthetic level to qualify the acceptance of the product. So, in many ways what one hears is used similarly to what one smells or even tastes. Over the years, researchers in psychoacoustics have developed many metrics for sound quality. However, the primary focus has been toward one end of the sound-quality acceptance spectrum---those sounds that annoy or irritate rather than those sounds that gain acceptance or please. The application of sound-quality techniques implies that well-defined specifications for the sound quality must be written so that a manufacturer is clearly able to accept or reject a product. This requirement will be even more acute in the future when many more products will be designed on one continent, built on another, and used on a third.