
CHAPTER 20. LIVE AUDIO EFFECT REFERENCE 272
20.18 Reverb
The Reverb Effect.
20.18.1 Input Processing
The input signal passes rst through high and low cut lters, whose X-Y controller allows
changing the band's center frequency (X-axis) and bandwidth (Y-axis). Either lter may be
switched off when not needed to save CPU power.
Predelay controls the delay time, in milliseconds, before the onset of the rst early reection.
This delays the reverberation relative to the input signal. One's impression of the size of a
real room depends partly on this delay. Typical values for natural sounds range from 1ms
to 25ms.
20.18.2 Early Reections
These are the earliest echoes that you hear after they bounce off a room's walls, before
the onset of the diffused reverberation tail. Their amplitude and distribution give an
impression of the room's character.
The Shape control sculpts the prominence of the early reections, as well as their overlap
with the diffused sound. With small values, the reections decay more gradually and the
diffused sound occurs sooner, leading to a larger overlap between these components. With
large values, the reections decay more rapidly and the diffused onset occurs later. A
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