Understanding Granular Delay

Clockwise from bottom left: Unfiltered Audio Silo, Output Portal and Arturia Efx Fragments.

Granular effects can be hugely powerful, but the chances of finding a preset that does exactly what you want are slim. So why not learn how to tame and tweak them?

There are numerous granular effect pedals and plug‑ins, but what exactly is granular delay? What can you expect from it, and how can you get it under control in your compositions and mixes? In this article, I’ll answer those questions, but since the scope of the sounds you can create with this type of effect is so broad, I’ve also created some audio examples to demonstrate the possibilities.

At its core, a granular delay stores audio into a temporary buffer, just as a conventional delay does, but then it breaks down the input signal into short sections that we call ‘grains’. These grains can be anything from a few milliseconds to several hundred milliseconds in length, but the real trick is that the individual grains can be processed in different ways before being sent to the output. Depending on the grain length and the types of processing applied to the individual grains (the most common are pitch‑shifting, reversal, time‑stretching and/or re‑ordering, sometimes with a random element applied), the effect produced can be anything from glitchy chaos to rich, evolving soundscapes.

Key Parameters

A typical granular delay will, of course, include the sort of controls you’d commonly find on a regular delay pedal or plug‑in (specifically delay time and wet/dry mix, along with a feedback control to recirculate the repeats) but you’ll also find a Grain Size control that determines the length of each grain. Smaller grains can be stretched and overlapped to produce smooth, textural effects, or they can be used to create glitchy effects. Longer grains can also be stretched and overlapped to produce flowing soundscapes, but they can also be used more overtly to produce rhythmic effects.

A Grain Density control will adjust the number of grains that are generated per second: the higher the density, the more likely it is that result will sound smooth and flowing, whereas low grain densities can create a variety of effects, from stutter repeats and glitches to crystalline jangles and sparkles if combined with pitch‑shifting.

There will usually be a pitch‑shift control too, which adjusts the pitch of individual grains. The most musically pleasing intervals will be octaves, fourths and fifths, but modest pitch detuning can also be useful. If applied using a randomiser, individual grains will appear at different pitches, which is an effect that can make for interesting ear...