Psychoacoustics—that is the branch of psychology concerned with the perception of sound and its physiological effects.

心声——这是心个分支， 研究声感知及其生效应。

The psychoacoustic algorithm finds elements in the audio that have exceptionally low volume sounds, very high-pitched sounds, or sounds very close together which the mp3 compression discards, thereby saving space and making it a lossy compression format.

心声算法频中查找量极低、调极高或声非常接近元素，而 mp3 压缩丢弃这些元素，从而节省空间并使其成为有损压缩格式。