Sunday, June 14, 2009

Deconstructing the Dominator

Dan's got a post over on his blog about reverse engineering the "hoover sound' found in the old school rave classic Dominator by Human Resource. He took a pretty technical approach and did various forms of analysis to come up with something that sound pretty good.
I thought I'd have a go myself, but I decided to take a more direct approach and look it up. I found this wikipedia article about it, it turns out that Human Resource were using a Roland Alpha Juno 2 to create that sound, a mid 80's digital/analogue hybrid synth. There's a good explanation of it's features here, importantly though, it does have a chorus unit built in, which Dan did identify as being the key feature of the sound.

Here's my re-construction attempt, I did start out to try and recreate the functions of an Alpha Juno 2, but in the end I mostly just improvised.

SynthDef(\aj2, {
arg freq = 440, gate = 1, lagLev = 0.01, predelay=0.01, speed=0.05, depth=0.01, ph_diff=0.5;
var width1, width2, width3, osc1, osc2, osc3, filterOut, mix, sig, modulators, numDelays = 8, lfo;
width1 =, 0, 0.8, 0.2).abs;
width2 =, 0, 0.8, 0.2).abs;
width3 =, 0, 0.8, 0.2).abs;
lfo =, 0, 5);
osc1 = + lfo), width1);
osc2 = + lfo), 0.5);
osc3 =*2) + lfo), width3);
mix =[osc1, osc2, osc3]);
modulators = Array.fill(numDelays, {arg i; * rrand(0.94, 1.06), ph_diff * i, depth, predelay);}); 
sig =, 0.5, modulators);  
sig = sig.sum;, sig.dup)

p = Pmono(\aj2, \dur, 0.24, \midinote, Pseq([40, 67, 64, 62, 62, 62, 62, 62], inf)).play;

I've got three pulse width modulated square wave oscillators here, modulated with low frequency SinOscs and some vibrato added with another low frequency SinOsc. These are put through a chorus efect taken from the tutorial, featured here before.

My patch is mostly based on random guesswork and a little bit of research, but it sounds okay, though probably not as good as Dan's scientific attempt.

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