Wave Interference & Beats

The Physics of Beats: When two continuous sound waves of slightly different frequencies are played together, they interfere with one another. As the waves fall in and out of phase, they create alternating moments of constructive interference (where their amplitudes add up, making the sound louder) and destructive interference (where they cancel each other out, making the sound quieter).

This regular pulsing variation in volume is called a beat. The mathematical rate at which these pulses occur—the beat frequency—is exactly equal to the absolute difference between the two original frequencies (|f1 - f2|).