Hanning function to control parameters of a sound

If you scale a one cycle of cosine wave by a factor of -0.5 and offset it by 0.5 you get a "Hanning function", which goes from 0 to 1 and back to 0 as smoothly as possible. That can be used to shape the amplitude of a sound, turning it on and off smoothly, or it can be used to modulate any characteristic of the sound. In this example we use a cycle~ object to generate a Hanning shape that repeats every four seconds (has a repetition rate of 0.25 Hz), and apply that to modulate several characteristics of a sound: center frequency, vibrato rate, vibrato depth, amplitude, tremolo rate, and tremolo depth.