What is psychoacoustics? Definition and examples

Because the experience of sound is so much related to mental perception and processing, studying our hearing has to take into account how we perceive sound. This is psychoacoustics: “the study of how humans [or animals] perceive sound”  and the sensations produced by sounds, and how we “interpret various auditory phenomena like pitch, loudness, and timbre”.

A more detailed definition would be to say that psychoacoustics is the psychophysical study of acoustics, where ‘psychophysics’ studies “the relationship between sensory perception (psychology) and physical variables (physics)”. 

Psychoacoustics, therefore, goes beyond the purely bodily or physiological, into the realms of how the brain interprets sound: “Is it a sound we recognize? Is the sound surprising or expected? Is it congruent with what our other senses are telling us?” 

While physical characteristics such as “the shape of our outer ears […] [or] the resonant properties of our skulls” affect what we hear, it is our brains which determine the way in which we hear it. They do so by cognitively making up for the physical limitations of our ears – by attempting to decipher the meaning of a given sound via context and experience.

The effect of context upon the perception of sound can be demonstrated by our different responses to the same sounds in different circumstances. For example, the explosion of a firework at a display is unlikely to trigger a sense of panic in the way that a car backfiring unexpectedly may do. The sounds themselves are comparable, but the context means that we process and respond to this auditory information in different ways.

The field of psychoacoustics emerged in the mid 1800s in response to the development of communications technologies. The word itself comes from Elements of Psychophysics, an 1860 text by Gustav Fechner, a German physicist, philosopher, and experimental psychologist, who is considered the founder of the discipline.

More than 160 years later, contemporary applications for psychoacoustics include:

• The development of “procedures, data, phenomena, and theories […] to diagnose and treat hearing loss”
• In music production: the ability to “manipulat[e] an unusual sound source to be heard as a conventional instrument”, and to “achiev[e] a pleasing mix [by creating] an even balance of frequencies across the spectrum”

The creation of emotional responses in audiences as a response to “ambient soundscapes for film and video games [which] give the background texture and bring the visual environment to life”.

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Featured photo by Cristian Escobar on Unsplash