Psychoacoustics

What Is Psychoacoustics?

Psychoacoustics is the scientific study of how humans perceive sound: how the ear and brain translate physical vibrations into the subjective experience of loudness, pitch, timbre and spatial location. Because perception differs systematically from acoustic measurement, psychoacoustics underpins every practical audio discipline, from mixing and mastering to sonic branding and product sound design.

Psychoacoustics in Practice

The founding reference is the set of equal-loudness contours measured by Harvey Fletcher and Wilden Munson at Bell Labs in 1933. Their curves showed that human sensitivity varies enormously with frequency and level: at quiet playback volumes the ear loses bass and treble first, which is why a mix that sounds rich in the studio can sound thin from a phone speaker, and why hi-fi systems long carried loudness buttons. Psychoacoustics also covers masking, the basis of MP3 compression, and streaming loudness normalisation measured in LUFS. For sonic branding the implication is practical: a sonic logo must be tested at the real volumes and on the real devices where audiences meet it, because perception, not the waveform, is what the brand actually owns.

Famous Example

The Fletcher-Munson equal-loudness contours, Bell Labs, 1933