Updated: Jul 26, 2022
Let’s talk science for a minute. Light energy can be viewed both as a wavelength and as its particle composition called photons.
Just like light, sound can be heard as a waveform or as particles. Granular synthesis produces sound that’s made up from tens to hundreds or thousands of sound grains. A sound grain typically lasts for just a brief moment (usually 1 to 100 milliseconds) which is close to the shortest sound event that we can hear with our natural hearing.
History of Granular Synthesis
Sound being viewed as particles can be traced back in history to the origins of the scientific revolution between 1588-1637 and was proposed in a scientific paper in 1616 written by the Dutch scholar Isaac Beekman. He believed that any vibrating object, like a piano or guitar string, cuts through the surrounding air into fragments that bounce around in every direction by the vibrations., which then enter the ear and bounce off of our ear drum. While his theory isn’t scientifically accurate, it paints a colourful image of how granular synthesis works.
Centuries later a British physicist by the name of Dennis Gabor, who also invented holography, wrote a pair of highly respected papers that combined theoretical insights from quantum physics with practical experiments. His theory in 1946 was that any sound could be reproduced using granular synthesis and he actually constructed a device based on a sprocketed optical recording system that was adapted from a film projector. He used this to conduct experiments in time compression and expansion with pitch shifting - changing the pitch of a sound without changing its duration. This was cutting edge technology at the time and was one of the stepping stones to sampling as we know it today!
The composer Iannis Xenakis was the first to compose a score using granular synthesis called Analogique A-B for string orchestra and tape. The composition is challenging to say the least, with chaotic string stabs and primal energy, but underneath the strings a warm gurgling of tape swooshes and chirps accompanies the piece and provides a contrast to the manic plucks and percussive strings.
So What Is Granular Synthesis?
Granular Synthesis is the process of taking an existing sound and chopping it up into smaller segments to create a new sound. As mentioned in the previous paragraphs, this can be done manually by splicing tape and rearranging the spliced sections, or by using one of the modern granulator plugins which does the splicing and shaping to output the grains of sound automatically for us.
When we input a sound into a granular synth, an amplitude envelope (also known as ADSR or Attack, Decay, Sustain and Release) shapes each grain, and the shape of the envelope will affect the sound that’s generated. The waveform within the grain can come from one of two sources: a synthetic waveform that can come from another synth, or a sampled waveform can come from a pre recorded sample. With either source, the duration, envelope shape and frequency can be adjusted. With sampled sources the location of the grains from within the sample can be chosen as well and that’s where the fun begins (at last!)
Types of Granular Synthesis
There are 5 types of granular synths known as:
1. Fourier and wavelet grids
2. Pitch-synchronous overlapping streams
3. Quasi-synchronous streams
4. Asynchronous clouds
5. Time-granulated or Sampled-sound streams
It’s the last type that we'll focus on for the rest of the tutorial as it’s become the most popular among sound designers and electronic musicians.
The time-granulation of sampled sound feeds the sample file through essentially an audio-wood chipper, spitting out grains of sound from the sample file in a new order creating new rhythms, melodies and textures. The granulator reads small segments of the sample file and applies an envelope to each grain, changing the shape of the segment which then alters the sound of the grain coming out.
Granular Synthesis Plugins
There are several popular granular synths on the market today. One of my favourites is Max For Live’s Granulator II, which is a powerful yet streamlined granular synth that's included with Ableton Live 10 and later. I especially like to create pads, atmospheres and drones with this synth although it’s capable of futuristic other-worldly textures as well.
I also really love using Portal by Output, which has a really well designed interface where I can easily find inspiration with while crafting new sounds. Technically it’s an effect rather than a synth but it produces similar results to a granular synth and uses the same principle. Portal makes it easy to turn on, find a preset and get great results and also offers more in-depth adjustments for fine tuning.
Lastly, granular synthesis really depends on the sample file being inputted into the synth and experimentation is key. I often search for field recordings from nature or mechanical noises or loops recorded from other synths to use as a sound source. It’s always surprising how many unique textures can come from a sampled sound. Have fun and be prepared to go down a rabbit hole with granular synthesis!