From Gabor's early thinking and experiments, one of the core ideas of granular synthesis is independent manipulation of time and pitch. Commercial time stretch, auto-tune, pitch shift and harmonizing algorithms are all closely related to granular synthesis. So all good granular synths should have a "speed" control that can slow down or reverse a sound without pitch shift, and should enable pitch shifts (e.g. playing different keyboard notes) while preserving playback timing.

The idea of a granular synth, as opposed to a time stretching algorithm, is to provide additional controls to impact how grains are selected, their length and many other attributes.

In this example we show Groc's playback "speed" and grain "size" controls. We demonstrate independent control of the playback direction and speed from the "direction" and size of the individual grains. This creates all kinds of interesting possibilities and reveals some surprising attributes about speech perception. Near the end of the example we can still perceive the macro structure of the sound (the words) in spite of the micro-sounds being time reversed.