Communication Acoustics: An Introduction to Speech, Audio and Psychoacoustics

17Sound Quality

The concept quality has two meanings. ‘Quality’ is used in this book as a synonym for ’excellence’, to grade or rank objects on a subjective scale of preferability such as ‘good–poor’, based on some explicit or implicit criteria. The other common meaning is related to categorization by type or class of objects. When two observations or entities cannot be compared on the same (metric) scale they are said to be qualitatively different. Such category-related sound quality pertains to perceived features, attributes, factors, dimensions, or properties of auditory events, such as loudness or roughness. However, in this book, the term ‘sound quality’ is limited to the meaning involving preferability or acceptability.

The inherent topic of the discussion on quality after its definition is evaluation. We experience some objects or states of the world as more desirable, valuable, positive, appealing, useful, or what have you than others. Although often weakly formulated and structured, such conceptions and rankings help us to set goals of action and to find better solutions to problems at hand. A widely used term in this context is quality of experience (QoE) (Le Callet et al., 2012), which denotes the overall acceptability of an application or service as perceived subjectively by the end user.

The theory of psychoacoustics, discussed in Chapter 8, uses the human as a simple metering device, where sound events evoke auditory events with attributes that can be measured ...