vfft pitch shifter
pitchshifter block
DESCRIPTION
The vfft pitch shifter alters the pitch of both polyphonic and monophonic audio in real-time. It leverages a phase vocoder with an added phase lock to significantly reduce reverberation artifacts.
At its core is a new FFT implementation (a modified ezfft) designed for higher overlaps, adjustable frame sizes, and low latency. This, however, comes with the trade-off of heavy CPU spikes.
Parameters include:
Pitch (coarse and fine) with A and B mods for coarse pitch
Non-modulatable parameters:
Block size
Overlap
Stereo/Mono
Free pitch/Snap to semitones
Phase lock/Pure phase vocoder
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Version 1.1:
Window Change: Updated windowing function from Blackman-Harris to Hann, reducing artifacts at low overlaps.
Pitch In: Added a "Pitch In" feature that adjusts the pitch knob, centered at mid C (no shift).
Demo Ensemble: Included a basic demo ensemble with a looper from Michael Hetrick's Euro Reakt 3.0, plus an LFO and delay.
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Version 1.2:
Overlap Compensation Fix: Resolved a bug in overlap compensation, enabling low overlap factors of 2 and 3.
Phaseless Bin Processing Fix: Fixed an issue with 1-dimensional outer bin (DC and highest bin) processing where an unset phase value introduced noise.
Output Volume Adjustment: Made adjustments to the output volume for better balance.
Block Size Update: Extended the knob range to include a block size of 2^13 (8192 samples per block, 4096 bins). While 2^14 isn’t currently supported due to array size limitations, you can explore extreme values by lowering the sample rate.
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