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. Final Cut Pro includes a Logic convolution reverb called Space Designer. See Space Designer Convolution Reverb.