Coded something new during last weekend, another classic effect which sounds great with many instruments:

12 stage mono phaser with internal (built in) LFO or an external modulation input

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Link to code:

Sound Sample (drum loop, stereo guitar track, synth)

Internal LFO is active when there is no modulation input signal connected. The waveform is similar to parabolic (often described as hypertriangular in hardware effects). Instead of a usual rate/depth controls the depth is set by two params: top value and bottom value. Incoming modulation waveform, internal or external, is then scaled to operate within that range.

Effect is not really cpu and ram heavy. T40 reported only 1% load.

input [0] - audio in
input [1] - modulation in (int16)
output[0] - audio output

One interesting use case of the phase shifter is a vibrato effect: set the feedback to 0.0, mix to full Wet (1.0) and adjust the top/bottom/rate values for the LFO to get different vibrato sounds.