Similar to the last example, there are two audio inputs which are added together. The first is a sinusoidal at 440-Hz.
The second is also a sinusoidal, but delayed by a vd~ object. The vd~ is similar to the delread~ object but the delay may be variable.
The delay changes for 10.5 periods to 20.5 periods over 1 second. It should be noted that we have destructive interference at either end (0 amplitude), and there are 10 beats overall, first between 0 and 0.1s, second between 0.1 s and 0.2s, etc.
The first beat is shown here. If our signal was composed of many frequencies, this patch will resonate at different frequencies at different times.