Beat Frequency Calculator
The throbbing two close notes make.
Work out Beat Frequency. The throbbing two close notes make. Written for the problem set you are stuck on.
Beat frequency
3 Hz
Heard as a slow throbbing, not a pitch
Two close tones interfere, alternately reinforcing and cancelling, and the throbbing that results is at exactly their difference in frequency. Below about 20 Hz it is heard as a pulsing rather than a pitch, and that is what tuning by ear means: adjust until the beats slow and finally stop. It is a null method, which is why it is so precise — you are listening for the absence of something rather than judging a pitch against memory.
How the Beat Frequency Calculator works
Enter two frequencies for the beat rate between them. Below about 20 Hz the difference is heard as pulsing rather than a pitch, which is exactly what tuning by ear listens for.
Also known as: beats per second calculator · tuning by beats · interference of two frequencies · beat frequency formula
Frequently asked questions
What is beat frequency?
The absolute difference between two frequencies. Two tones at 440 and 443 Hz produce three beats per second.
How do musicians tune by beats?
By adjusting until the beating slows and stops. It is a null method — you are listening for the absence of pulsing rather than judging a pitch — which makes it far more precise than matching by ear alone.
When do beats stop being audible as beats?
Above roughly 20 Hz the pulsing becomes too fast to follow and the ear hears two separate tones, plus a roughness where they interact.
Do beats happen with light?
Yes, and the same maths applies. It is the basis of heterodyne detection in radio and of optical beat measurements, where two lasers produce a difference frequency low enough to measure electronically.
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