FXAlg #15: Finite Verb
Algorithm Reference-30
FXAlg #15: Finite Verb
ÒEnvelopedÓ reverberation algorithm
Allocation Units:
3
In this algorithm, the left and right sources are summed before being fed into a tapped delay line, which directly
simulates the impulse response of a reverberator. The taps are placed in sequence from zero delay to a maximum
delay value, at quasi-regular spacings. By varying the coefficients with which these taps are summed, one can create
the effect of a normal rapidly building/slowly decaying reverb or a reverse reverb which builds slowly then stops
abruptly.
A special tap is picked off the tapped delay line and its length is controlled by Dly Length. It can be summed into
the output wet mix (Dly Lvl) to serve as the simulated dry source that occurs after the reverse reverb sequence has
built up and ended. It can also be fed back for special effects. Fdbk Lvl and HF Damping tailor the gain and
spectrum of the feedback signal. Despite the complex reverb-like sound of the tapped delay line, the Feedback tap
is a pure delay. Feeding it back is like reapplying the source, as in a simple tape echo.
Diagram of Finite Verb
Dly Length and Rvb Length range from 300 to 3000 milliseconds. With the R1 Rvb Env variants, Rvb Length
corresponds to a decay time (RT
60
).
To make things a little more interesting, the tapped delay line mixer is actually broken into three mixers: an early,
middle, and late mixer. Each mixes its share of taps and then applies the submix to a lowpass filter (cut only) and a
simple bass control (boost and cut). Finally, the three equalized sub mixes are mixed into one signal. The Bass and
Damp controls allow special effects such as a reverb that begins dull and increases in two steps to a brighter sound.
L Input
R Input
Dry
Dry
L Output
R Output
Early
Delay
Mid
Delay
Late
Delay
Delay
Diffusion
Feedback
Level
HF Damping
Delay Level
Bass
HF Damp
Wet
Out
Gain
