Friday, August 7

Let's get granular!

From wiki:

"Granular synthesis is a basic sound synthesis method that operates on the microsound time scale. It is often based on the same principles as sampling but often includes analog technology. The samples are not used directly however, they are split in small pieces of around 1 to 50 ms in length, or the synthesized sounds are very short. These small pieces are called grains. Multiple grains may be layered on top of each other all playing at different speed, phase and volume.
The result is no single tone, but a soundscape, often a cloud, that is subject to manipulation in a way unlike any natural sound and also unlike the sounds produced by most other synthesis techniques. By varying the waveform, envelope, duration, spatial position, and density of the grains many different sounds can be produced.
The result is usable as music, sound effects or as raw material for further processing by other synthesis or DSP effects. The range of effects that can be produced include amplitude modulation, time stretching, stereo or multichannel scattering, random reordering, disintegration and morphing."

The Malstrom synthesizer in Reason uses graintable synthesis. And while I love it, the one thing I think it's really lacking is the ability to load your own waveforms. Here's a little trick on how to use a NN19 sampler in a combinator as a Granulizing device. I've made the combinator template available for download, but I think it would be best if I explained it a bit.

The NN19 Sampler, unlike it's more powerful sibling, allows you to map the sample start time to a rotary knob in a combinator. While this in itself is quite cool, what really makes it interesting is if you also load a Malstrom into the combi and control the rotary with one of Malstrom's Modulators. To do this all you need to do is flip your Reason rack around and connect a cable from Malstrom's Mod A output to the Rotary 1 input (on the top of the combinator's backside.) Now you can use all the different waveforms in Mod A to control the Sample Start time when notes are pressed. My favorite waveform to use for this is #13, the upward slant. With this waveform you get the Sample Start knob moving in the same direction as regular playback of the wav file. Now what I like to generally do at this point is draw a pattern into the sequencer with the pencil tool. You'll want the notes to be fairly fast (at least 1/16 notes) and it's best if you play around with a few different note values. Straight 16th or 32nd notes sound boring after awhile. In the refill accompanying this tutorial I've included a dozen different midi patterns to get you going. After importing a midi file, just load up the sample you want to granulize into the NN19 and press play.

Now that you have an idea about how the combinator works let's discuss the different controls and settings:

Rotary 1 - Sample Start - with this knob turned all the way to the left (and Mod A on waveform #13) the whole wav file will be swept. If you move the knob further right, less and less of the sample will play.

Rotary 2 - Osc Env Amt - this knob controls the Oscillator Envelope Amount knob on the NN19 sampler. Try playing with it a bit and you'll see how it pitch-shifts the wav file in an unusual way. This is fun to play with for glitchy and sci-fi sounds. When it's set dead center it has no effect.

Rotary 3 - Granular Curve - controls the waveform for Malstrom Mod A. When it's set on 52, waveform #13 is called up.

Button 2 - Stutter - this button turns on and off the 1-shot control for Mod A. This makes it so every time a note is pressed the waveform starts over, thus giving you a stuttering type sound in this scenario.

Mod Wheel - this control is set to change the rate for Mod A, from 8/4 to 1/32

Some other controls and functions you'll probably want to look at are the LFO in NN19 for starters. I like to set this to filter with either a triangle or one of the ramps (saws). This will give you that sweeping sound at lower rates or gurgling at faster settings when the amount knob is turned all the way up. I generally leave it at either 4/4 or 8/4 with the amount just under half way. I also have Mod B on the Malstrom controlling the Resonance on the NN19's filter. If you flip the rack around you can determine how strong you want this effect. On the Granular Template it's set to zero. Also, depending on what kind of sound you are going for you'll probably want to play with the reverb's dry/wet setting, as well as the delays. One last item, I've found that when going for glitchy sounds sometimes it sounds better with the Low BW button pressed on the NN19. For added fun try hooking up an RPG-8 arpeggiator to the combinator and dropping the midi pattern into the arp's sequencer track. And finally, don't forget to use the Pitchbend!

Here's an example of a drum loop granulized:

And the link for the refill:

Granular Tutorial Refill

There's also a great short film on VBS about the creator of granular synthesis:

Curtis Roads


meowsqueak said...

Awesome - love it! Great work :)

Lewis.72 said...

Thanks! Glad you like it. I've found it sounds really cool on drums when you have a track playing of the regular beat and then add the granulized sound on top of it fading in and out. Let me know if you figure out any cool tricks.

Phi Sequence said...

I love this graintable. I've created a similar idea using matrixes instead of the malstrom. A few things though. You have the Mod A controlling the sample start, so if you move Rotary 1 to the right or left won't make a difference on the sample start, because the Mod A controls where it starts -- and the pot is turned all the way right so I don't think this is having the effect you want. If you remove the cv cable, then yes it will indeed affect the sample start as you describe.

Otherwise, this is very cool and a really nice way to get some glitchy effects out of a sample. sweet!

Lewis.72 said...

Can't wait to see your Grain Synth on Phi Sequence! Using matrixes is a great idea, much quicker then drawing in or importing midi files. On mine, Rotary 1 is set-up to control the NN-19s Start Time, which you're right is being controlled by the Malstrom's Mod A. If you move Rotary 1 it changes the length of the grain... probably not the most eloquent way of doing this in hindsight and a bit confusing. Cheers!