Psychoacoustics

Psychoacoustics is the study of subjective human perception of sounds.

The most important areas of psychoacoustics are audio compression and [speech recognition]?.

There are some interesting properties of the human sense of hearing. Sounds of low (<20 Hz) and high (>20kHz) frequencies are almost inaudible to humans, while sounds of some frequencies are perceived as louder that sounds of the same energy and some other frequencies.