Simple amplitude control

When you're changing the amplitude of a sound, if the amplitude is changed very suddenly and significantly, it may create a sudden discontinuity in the waveform which will be heard as a high-frequency click. (That phenomenon is demonstrated in the example "Click resulting from amplitude change".) To avoid that problem, it's necessary to interpolate sample-by-sample from the old amplitude value to the new value, over some small period of time, to create a slightly more gentle fade to the new amplitude factor.

Route signal for audio and control data

The way audio Max compiles audio signal networks is, whenever audio is turned on, MSP outlets send out the message ‘signal’. (In other words, that’s how Max knows how MSP objects are connected to each other, and thus knows how to calculate the audio signal network.) The [route signal] object detects the selector ‘signal’ and sends a ‘bang’ out its left outlet in response. The [t signal] object converts that ‘bang’ back into the message ‘signal’.