Sound II Reading

2.2. Loudness/Time

Loudness/Time Perception

Loudness level can influence perceived time relationships. When two sound begin simultaneously, they will appear to have staggered entrances if one of the two sounds is significantly louder than the other. The louder sound will be perceived as having been started first.

Loudness/Duration

Duration can distort the perception of loudness. Humans tend to average loudness levels over a time period of 2/10 of a second. Sounds of shorter duration will appear to be louder than sounds (of the same intensity) with durations longer the 2/10 of a second.

Loudness/Timbre

Timbre can also influence loudness perception. Sounds with complex spectrum will be perceived as being louder than sounds that contain less harmonics. Also sounds with more complex spectrum with a strong presence of overtones will be perceived as louder than sounds containing mostly proportionally related harmonics. Following this principle, a change in timbre during the sustain duration of sound will result in a perceived change of loudness.