• physics: beat is the perception of the sum of two close frequencies as one frequency that oscillates between zero intensity and full intensity, caused by the alternating constructive and destructive interference. Beating is heard as a pulsation in loudness of two close frequencies, and , at the rate of . Thus at the unison and as the difference between and increases, the speed decreases till beyond a certain proximity beating stops and a roughness is heard instead, after which the two pitches are perceived as separate. The composer Alvin Lucier has written many pieces which feature interference beats as their main focus. Musicians may used interferance beats to objectively check tuning at the unison or other simple intervalss.

  • music: beat (music) is any of the periodic transient signals in music that mark the rhythm.
The beat can also mean solely the bass and snare drums of the rhythm. DJs often beatmatch the songs that they play.
Interference beats are used in tuning, see tuning and physics above.