Soundtrack Pro 3 Effects Reference (en).pdf - Help Library - Apple

126 Chapter 10 Reverb Effects
Plates, Digital Reverb Effects, and Convolution Reverb
The first form of reverb used in music production was actually a special room with hard
surfaces, called an echo chamber. It was used to add echoes to the signal. Mechanical
devices, including metal plates and springs, were also used to add reverberation to the
output of musical instruments and microphones.
Digital recording introduced digital reverb effects, which consist of thousands of delays
of varying lengths and intensities. The time differences between the original signal and
the arrival of the early reflections can be adjusted by a parameter commonly known as
predelay. The average number of reflections in a given period of time is determined by
the density parameter. The regularity or irregularity of the density is controlled with the
diffusion parameter.
Today’s computers make it possible to sample the reverb characteristics of real spaces,
using convolution reverbs. These room characteristic sample recordings are known as
impulse responses.
Convolution reverbs work by convolving (combining) an audio signal with the impulse
response recording of a room’s reverb characteristics. Soundtrack Pro features a
convolution reverb called Space Designer. See Space Designer Convolution Reverb.