flanger~

This block applies a flanger effect on the incoming mono audio signal, that is the original signal delayed with a variable delay. It gives a metallic resonant effect like a jet plane taking off or landing. You can choose between several control curves and a free input for a control curve. You also have to include an argument otherwise the effect won't work.

version

waves v2.0: look at the documentation of this block to see what it does [pd]
v1.0: built 4/04/2007 with Pd v0.40-2 [pdf]
v1.1: built 5/04/2007 with Pd v0.40-2 [pdf]
waves block added for more choices in control curve
free control added
v1.2: built 13/04/2007 with Pd v0.40-2 [pd][pdf]
waves block is separated in development and documentation
thus no real differences with previous version, alone the documentation has changed.
v2.0: built 13/04/2007 with Pd v0.40-2 [pd][pdf]
a feedback loop is added and the level and feedback are unified into one control

interface

Input1: incoming mono audio signal
Input2: modulation frequency (MODFREQ) ranges from 0-127 (representing normalized values between 0 and 1). This parameter specifies how fast the delayed signal changes between leaping forward and lagging behind. It's modulation curve is selectable in the waves block: one can cycle through different waveforms by pushing a specific button (see documentation on waves). The amplitude is fixed to 10. If one wants to use a different amplitude for the control curve of the variable delay, the previous version should be used.
Input3: the feedback level (FBK) ranges from 0-127. This parameter specifies the range of the variable delay, how far it lags behind or leaps forward. It represents the maximum difference from no delay. When leaping forward the pitch gets higher and vice versa. If it's zero, the loop is off.
Input4: an inlet for a control signal that directly controls the variable delay time. Be careful to give a quite low frequency signal with an amplitude that is not too big.

Output1: outgoing mono audio signal: this is only the wet signal, the original signal delayed with a variable delay.

implementation

The input signal is written into a delay line.
The waves block outputs a normalized waveform with a frequency specified by the MODFREQ parameter.
The amplitude is fixed to 10 by a multiplication. This waveform is then used as the varying delay time for the vd~ block. When the values of the waveform are greater than zero, the delay will leap forward (with a maximum of one block size), when it's smaller it leaps behind (the delay time is greater).

This signal is put in the feedback loop, which feedback level is controlled by a simple amplitude logic consisting of scale block (/127) and a multiplication.

It is important to include an argument. This is needed to make, at the same time, 2 different flanger computations possible. Otherwise the delay-lines of several flanger effects used would have the same name. Now with the dollar sign, the name of the argument is inserted.