Vocoder for OLPC
Skills: Scripting (CSound), DSP
When Dr. Boulanger announced that the One Laptop Per Child program was going to be giving thousands of free computers to kids in Africa and bundling it with CSound, I thought this an amazing way to introduce kids to computer music. When he said that any patches / instruments that were written in CSound would be considered for shipping as part of the standard OLPC bundle, I jumped at the opportunity.
I choose to write a vocoder because at the time it was the electronic instrument I wanted to know the most about but was not familiar with at all. Basically as you can see in this diagram, a vocoder is just a carrier signal being passed through a bunch of band pass filters, and a modulator signal (input) opening those filters based on an envelope follower on the amplitude of the modulator. I hope many kids learned about sound design by using this patch, but I read that actually many students were just using these laptops to browse things they shouldn’t be seeing on the web. Se la vie.