To play short grains of sound, especially ones randomly chosen from a sound file, it's usually necessary to impose some sort of "window"—an amplitude envelope—to taper the ends of the grain in order to avoid clicks. This patch shows how to generate four types of window function, and read through them with a phasor.
To sync an LFO to the onset of a note, drive it with a phasor~ object. Send a phase value of "0" into the right inlet of phasor~ when the note starts, as seen in this example.
This example combines seven pre-recorded saxophone sounds, slowly modulating several aspects of their playback to create an ever-changing mix.
The real value of phasor~ is that it provides a very accurate way to read through (or mathematically calculate) some nonlinear shape to use as a control signal (or even as an audio signal). Among other things, it might be used to create a "window" shape that can serve as an amplitude envelope for a sound. This patch demonstrates five different ways to create window or waveform shapes with phasor~. We'll discuss them (in good Max fashion) from right to left.
In signal processing, a "window" is a function (shape) that is nonzero for some period of time, and zero before and after that period. When multiplied by another signal, it produces an output of 0 except during the nonzero portion of the window, when it exposes the other signal. The simplest example is a rectangular window, which is 0, then briefly is 1, then reverts to 0. The windowed signal will be audible only when it is being multiplied by 1––i.e., during the time when the rectangular windowing occurs.
This patch is designed to be used as an abstraction (subpatch) in another patch, such as the example "Mixing multiple audio processes". In order for that example to work, you should download this example and save it with the filename "pinger.maxpat" somewhere in the Max file search path.