Psychoacoustics is the scientific study of sound perception. More specifically, it is the branch of science studying the psychological and physiological responses associated with sound (including speech and music). Topics of study include perception of the pitch, timbre, loudness and duration of musical sounds and the relevance of such studies for music cognition or the perceived structure of music; and auditory illusions and how humans localize sound, which can have relevance for musical composition and the design of venues for music performance.