Beats

Visualizing the interference of two waves with slightly different frequencies.

The Concept: Beat Frequency

When two sound waves of similar but slightly different frequencies interfere, the resulting sound has a periodically varying amplitude. This variation is what we perceive as beats. The frequency of these beats—how often the sound gets loud—is simply the difference between the two original frequencies: $f_{\text{beat}} = |f_1 - f_2|$.

What to look for

  • The simulation shows two source waves and their superposition below.
  • Notice that when the frequencies are very close, a slow "beat" pattern emerges in the resultant wave.

Controls

Beat Frequency

Wave 1 ($f_1$)

Wave 2 ($f_2$)

Resultant Wave (Superposition)