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# musical sketchbook 15
- URL: https://wootangent.net/musical-sketchbook-15/
- Published: 2009-03-21T08:22:25.000Z
- Updated: 2009-03-21T08:22:25.000Z
- Author: Leigh Dyer
- Tags: Sketchbook, #Migrated-1792830072870, #wp, #wp-post, #Import 2026-10-24 08:21

Download [15.mp3](http://electronaut.linuxgamers.net/~lsd/music/sketchbook/15.mp3?ref=wootangent.net)

Today's sketch is [about as cliched as they come](http://electronaut.linuxgamers.net/~lsd/music/sketchbook/15.mp3?ref=wootangent.net), but I still dig it. I used an open-source [vocoder](http://www.sirlab.de/linux/descr%5Fvocoder.html?ref=wootangent.net), and while the results are a bit rough, that may be due to other factors, such as the low quality of the vocal recording using the Rock Band mic. I used a simple sawtooth from the Blofeld as the "carrier" sound, playing it to get the changes in pitch -- the pitch in your voice when using a vocoder is discarded, so the result would have been monotone if I just held the same note, regardless of what pitch I sang.

Getting this all working is actually a bit fiddly at the moment, since it involves taking audio from two separate sources -- my sound card (for the carrier signal from the Blofeld) and the USB mic -- and that's only really possible in the very latest version of JACK, which won't be rolled in to Ubuntu until the 9.04 release next month. For now, I had to compile the latest JACK myself, and then convince all of the apps involved (the vocoder itself, JACK Rack, to amplify the signals prior to vocoding, and TimeMachine to capture the results) to use that instead of the standard version.