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Therafiltering

Thu, 28 Jun 2007

A guide to creating a touchless volume and filtering controller using simple theremin and vocoder, with sound sample.

Sound sample of the result.

Well, I just decided to call it therafiltering. This is an original (as far as I know) technique to create an interesting touchless, non-linear filtered synth sound.

You will need:
A theremin
A vocoder or similar

Now that I've eliminated everyone, I'll explain.
Anyone who has a theremin will know one of the hardest things is trying to play a melody on it on the correct notes. Moving your hands in the air isn't conductive to accuracy.

While pondering other options I had an idea. I set things up like so:
- Play the desired melody on another instrument
- Use this instrument as the carrier for the vocoder
- Use the theremin as the modulator for the vocoder

Interestingly, the theremin now acts much like an EQ and volume control in one, albeit an EQ you can control by waving your hands in the air!

My theremin's just a cheap kitset one from Jaycar (~$55US) so it only makes a sine wave with a few random harmonics. As the sine wave moves up and down in pitch it triggers different parts of the instrument sound similar to a resonance filter.

My vocoder is just the Morphoder Waves plug-in (which isn't quite a vocoder) in ProTools. I played a MIDI track on a keyboard and used that as in input.


Theremin track on top and MIDI instrument track underneath (triggering internal synth).

All up it sounds like this.

Not that exciting? Well, I thought it was worth sharing anyway, and that's only the result after 10 minutes of messing around. Feel free to use this technique in your multi-platinum R&B recordings.