Harmony - beats

Ben Sparks
Click left buttons to play/stop sounds (check your volume is not maximised first, or you might get a shock). The sliders or input boxes let you change the frequency of the two sounds. Click Show Sum (and turn of the other two) to see the mathematical sum of the functions on the graph. Try making the two frequencies really close (say 440, and 444), and adjusting the x-axis zoom by shift-dragging the x-axis. On zooming out you'll see the 'beats' that you can hear in the joint sound as a 'wobble'.