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: $f_{\text{beat}} = |f_1 - f_2|$.
How to Use the Lab
- The simulation shows two source waves and their superposition below.
- Press Start to animate the waves.
- Adjust the frequencies of Wave 1 and Wave 2.
- Notice that when the frequencies are very close, a slow "beat" pattern emerges in the resultant wave.
- Listen closely! You should hear the beats when the simulation is running.