WaveWarp 2.0 Component
      
Flangers:
Basic Feedback Flanger Unit
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Functional Description
Basic building block for constructing a feedback flanger effect.
The output is a delayed version of the input, with a delay length
which varies in time. An internal feedback path connecting the
output of the time-varying delay to its input, enhances the effect.
The characteristics of the time-varying delay are adjusted
in the Parameter Window, as summarised in the
following table. Stereo signals have separate adjustments for left and
right channels.
| Parameter | Purpose |
|---|
| "Modulation" buttons | Selects the shape of the time-varying delay profile |
| "Delay" slider | Sets the maximum delay length |
| "Rate" slider | Sets the rate at which the time-varying delay sweeps through its profile |
| "Depth" slider | Sets the depth of modulation of the time-varying delay: a value of 0 corresponds to a constant delay of the maximum length;
a value of 1 corresponds to maximum modulation of the delay whereby the delay length sweeps from zero to the maximum length, following a time-history in accordance with the chosen profile |
| "Skew" slider | Adjusts the time-asymmetry of the shape of the delay profile (only enabled for certain shapes). A value of 0.5 corresponds to a symmetric profile. |
| "Feedback" slider | Adjusts the internal feedback gain. (CAUTION: values approaching unity can lead to undesirable instabilities.) |
| "Feedback polarity switch" checkbox | Toggles the polarity of the internal feedback gain (i.e. switches between negative and positive feedback). |
| "Output" slider | Adjusts the amplitude of the output signal. |
IMPORTANT: In order to achieve the feedback flanging effect, this component must be
connected in parallel with the original signal. On its own, it simply acts as a
time-varying delay (with feedback) and will not produce a flanging effect. A multi-voice feedback flanger
can be obtained by connecting multiple Basic Feedback Flanger Units in parallel
with the original signal.
Algorithm
The time-varying delay is implemented using a circular buffer with linear (first order) interpolation
to avoid discontinuities
(see
[Moore]
chapter 4.2.5 for further information).
The delay time-history is stored
in a wavetable, and is scanned using a table-lookup oscillator algorithm
(see
[Moore]
chapter 3.1.7 for further information).
See
[Roa] p.437
for an introduction to flanging, and
[HRM]
for general information on audio effects.
Signal Implementations
| Audio signals | Control signals | Description |
|---|
| Single input single output mono-mono | n/a | Effect applied to mono input, sent to mono output |
| Single input single output mono-stereo | n/a | Effect applied to mono input with separate settings for left and right stereo output channels |
| Single input single output stereo-mono | n/a | Effect applied with separate settings to left and right stereo input channels, then averaged and sent to mono output |
| Single input single output stereo-stereo | n/a | Effect applied with separate settings to left and right stereo input channels for left and right stereo output channels, respectively |
Related components:
Example DrawingBoards illustrating usage:
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