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| WaveWarp 2.0 Component
      
Reverbs:
Functional Description
Comb filter with a low-pass element built into the
feedback loop,
for use as a unit reverberator
according to the design in
[Moorer2]
(based on the ideas of Schroeder).
Algorithm
A verbatim implementation of the filter shown in Fig. 5 of
[Moorer2].
The transfer function, T(z), is given by:
| T(z) = z-m /(1 -g2 z-m -g1g2 z-(m+1)) |
where the delay, m, and gains, g1 and g2, are adjusted via the Parameter Window, as summarised in the
following table.
| Parameter | Purpose |
|---|
| "Delay" slider |
Adjusts the comb delay, m, expressed in milliseconds. The available range
of 50 to 80 ms is recommended in
[Moorer2]
|
| "Gain" slider |
Adjusts the quantity denoted g in
[Moorer2]
which determines the "reverberation time".
A value of 0.83 gives a reverberation time of about 2 seconds, for delays
between 50 to 80 ms. The filter gains g1 and g2 are related to g
according to the following formula
(from [Moorer2]): g2= g (1-g1).
|
| "Gain 1" slider |
Adjusts the low-pass filter gain, g1, which is intended to simulate the absorption
of high frequencies by the air inside a room. Table 2
in
[Moorer2]
lists suitable values for g1 for a range of delays, obtained from a series of
optimizations
designed to match the model filter frequency reponse with measured data.
|
The delays are implemented using circular buffers.
For more information on
room acoustics and
reverberation, see, for example:
[Roa] p. 477-492,
[Moore] p. 370-394,
[Ros]p. 459-493,
[Be] p. 172-222,
[Zo] p. 181-205,
plus various articles in
[AES8]
and
[AES16].
Signal Implementations
| Audio signals | Control signals | Description |
|---|
| Single input single output mono-mono | n/a | The mono audio input is filtered and sent to the mono audio output. |
| Single input single output mono-stereo | n/a | The mono audio input is filtered and sent (in duplicate) to the stereo output channels. |
| Single input single output stereo-mono | n/a | The stereo audio input channels are averaged, then filtered and sent to the mono audio output. |
| Single input single output stereo-stereo | n/a | The stereo audio input channels are are averaged, then filtered and sent (in duplicate) to the stereo output channels. |
Related components:
Example DrawingBoards illustrating usage:
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