Beat
Article
In acoustics, a beat is a periodic variation in loudness produced when two tones of slightly different frequencies are heard together. Their waves alternately reinforce and cancel one another as their relative phase changes.
The beat frequency equals the absolute difference between the two original frequencies. For example, tones at 440 and 442 hertz produce two beats per second.
Beats are easiest to hear when the frequencies are close. As the difference increases, the fluctuations become faster and may eventually be perceived as roughness or as two separate pitches rather than distinct pulses.
Musicians use beats when tuning instruments, because the beating slows as two notes approach the same frequency. Beat phenomena also appear in heterodyne detection, interference measurements, acoustical testing, and the interaction of nearby resonances.
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- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Beat_(acoustics)