Beats with two tone generators

Two tunable tone generators were constructed to demonstrate beats.

The tone generators were tuned to essentially the same pitch and then one was slowly tuned up or down. The result was a strong pulsating tone, the pulsations becoming more rapid as you tune farther away either upward or downward in pitch. The two displays above show the combined tones on a fast sweep to show the wave shape, and on a much slower sweep to show the rising and falling amplitude of the combined sounds.

Click on the player at right to play the tone which produced the above display. The composite tone has a frequency of about 238 Hz. The time between minima is about 0.62 seconds, corresponding to a beat frequency of about 1.6 Hz. This implies that the two tones were 1.6 Hz apart in frequency.

The above sound amplitude trace shows the beat phenomenon as one tone generator is tuned upward in pitch.

Click on the player at right to play the sound of the tone generators as one is tuned upward while the other remains at its original pitch.


Hearing concepts

Traveling wave concepts
HyperPhysics***** Sound R Nave
Go Back