Apple Soundtrack Pro 3 - Manual (Page 277)

Reverb and Delay Effects
Reverbs and delays work by copying a part of the audio signal, delaying it for a brief
period of time, and then playing it back with the original signal. The delayed signal can
be played back multiple times and can be modified in a variety of ways.
Delay
A delay effect stores the audio signal and then plays back each repetition at a regular
rate of time after the original signal. Delays can be used to double individual sounds (for
example, making it sound as if a group of instruments is playing the same melody), to
achieve echo effects (making it sound as though the sound was occurring in an immense
space), and to enhance the stereo position of tracks in a mix. Delay effects are not
commonly used on an overall mix except to achieve special effects (such as to create an
“otherworldly” sound).
Delay effects let you set the delay time, the time between the original signal and the
delayed signal. Delays often provide parameters for feedback (also called regeneration),
which let you set how much of the delayed signal is fed back into the delay’s input,
creating more repetitions of the delay (like the number of “bounces” in an echo). Specific
types of delay have other parameters: tap tempo delays let you set the delay time by
physically tapping a key or controller; stereo delays include parameters for the pan position
of the output signal, which can be shifted over time using a low-frequency oscillator
(called an LFO).
277 Chapter 10 Working with Audio Effects