Psychoacoustics

Psychoacoustics is the study of subjective human perception of sounds. Effectively, it is the study of psychology of acoustical perception.

Masking effects

In some situations an otherwise clearly audible sound can be masked by another sound. For example, conversation at a bus stop can be completely impossible if a loud bus is driving past. This phenomenon is called masking. A weaker sound is masked if it is made inaudible in the presence of a louder sound.

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If two sounds occur simultaneously and one is masked by the other, this is referred to as simultaneous masking. A sound close in frequency to the louder sound is more easily masked than if it is far apart in frequency. For this reason, simultaneous masking is also sometimes called frequency masking. The tonality of a sound partially determines its ability to mask other sounds. A sinusoidal masker, for example, requires a higher intensity to mask a noise-like maskee than a loud noise-like masker does to mask a sinusoid. Computer models which calculate the masking caused by sounds must therefore classify their individual spectral peaks according to their tonality.

Related Topics:
Simultaneous masking - Sinusoidal - Noise-like

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Similarly, a weak sound emitted soon after the end of a louder sound is masked by the louder sound. In fact, even a weak sound just before a louder sound can be masked by the louder sound. These two effects are called forward and backward temporal masking, respectively.

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