Granular Pitch

A granular pitch shifter that transposes audio up or down two octaves without changing its speed. Built for harmonizing, octave-stacking, formant-bending vocals, or detuning a sound until it shimmers — it works in stereo and keeps the original image intact.

How it works

Instead of resampling, the engine slices the recent input into a pool of 32 short grains, windows each one with a smooth Hann envelope, and overlap-adds them back, with Density setting how many grains stack at once. Each grain is read from the buffer at its own pitched rate, so the perceived pitch changes while the playback duration stays fixed. Short grains track transients tightly with a crisp, grainy edge; long grains sound smoother and more continuous but smear fast material.

Controls

• Pitch — transposition from -24 st (two octaves down) through unity at centre to +24 st (two octaves up).
• Grain — grain length from 20 ms to 200 ms; the core texture control, trading transient detail against smoothness.
• Mix — dry/wet blend; at 100% you hear only the shifted signal, lower values fold the original back in for parallel harmonies.
• Density — how many grains overlap at once, from 1.5x to 4x; pull it low to space the grains apart for a sparse, rougher texture that ripples at the grain rate, push it high to layer more grains into a dense, smeared shimmer.

Inputs & outputs

• inL / inR — stereo audio in; feed both for a coherent stereo-shifted result, or one for mono.
• Pitch / Grain / Mix / Density CV — voltage control over each knob; patch an LFO or envelope to play or modulate transposition, grain size, blend, or texture density.
• outL / outR — the processed stereo pair.

Tips

• Stack two instances at +12 st and -12 st into a mixer for an instant octave chord.
• Slow modulation into Grain CV keeps the texture alive without touching pitch — subtle motion on pads and drones.
• Pull Mix back below 50% and detune Pitch a few semitones from unity for thick, chorus-like doubling.