jdn » fractal

Machinedrum Recursive Sampling Test 02

jdn — Mon, 16 Nov 2009 06:46:21 +0000

So this is another example of using the MD’s internal sampler to create a recursive “feedback loop” of sampling and resampling and resampling.… This has a tendency of psychedelically twisting the underlying beat. The way this stuff sounds has really surpassed my wildest dreams.

MD Recurse Test 02

If you’re a Machindrum SPS-UW user, there are two tricks to getting this working nicely:

Use the last four slots to setup two sample record machines, and two sample playback machines. Interleave the recording and playback so you get coverage of the entire measure. For example, have R1 sample the first half of the measure, and P1 start playing at the second half of the measure. Likewise, set R2 to record starting at beat 3, and have P2 triggered at beat 1. This is important to get the proper density of sampling to make this work with full feedback. I did this with a 16-step pattern, but it would probably work similarly when extended for longer loops.

Use a Control All machine (or function-knob twists) to mangle the synthesis parameters, and optionally the insert effects to mess things up.

Please share this post, or check out my music on SoundCloud if you like what you hear!

Photo courtesy Patrick Denker.

Machinedrum Recursive Sampling Test 01

jdn — Wed, 04 Nov 2009 06:42:28 +0000

This was a first test at using the Machinedrum’s internal sampler recursively. I was trying to emulate my fractal wavetables sounds in hardware, as closely as the MD could do it.

MD Recurse Test 01
Patience… it gets really cool from around 1:00 on.

Fractal Wavetables

jdn — Fri, 20 Mar 2009 22:59:09 +0000

Based on work by composer Terran Olson, I’m releasing a Processing applet that lets you play with recursive/fractal sound synthesis by setting a few sliders.

Background

Inspired by an article on CDM, and Terran Olson’s work in particular, I dug into creating a slightly more general version of fractal set synthesis.

In essence, you use a bank of sliders to give the program a wavetable “seed”, which is immediately subdivided into sound — each sample is replaced by a copy of the wavetable, multiplied by the old sample value, and so on.…

This recursion continues until the desired length of audio data has been generated. The initial value always begins at “1″. For a seed of “1 0.5 1″, you get the following as the first three steps:

1 =>
1 0.5 1 =>
1 0.5 1 0.5 0.25 0.5 1 0.5 1 =>
1 0.5 1 0.5 0.25 0.5 1 0.5 1 0.5 0.25 0.5 0.25 0.125 0.25 0.5 0.25 0.5 1 0.5 1 0.5 0.25 0.5 1 0.5 1 => …

Try it

Click the thumbnail below to run the applet in your browser (requires Java):

Or get the downloadable application version here (so you can save out audio files):
Mac OS X version
Windows version
Linux version

If you’re curious about how this was written, the public git repository for this project lives at:
http://wiki.github.com/jdnorthrup/fractalwavetablesketch

Thoughts

Initially, I found the whole idea that the music can be self-similar from the waveform level, up to the “LFO” level, up to the rhythmic phrase, to the overall flow of a passage of sound — rather mind-expanding.

Interestingly, the sounds produced from this can sound spectacular through deep reverbs and other processing. They’re almost the same amplitude at all frequencies in their range, quite unlike natural harmonic spectra. Try running a steep resonant bandpass across some of the more complex sounds.

If you do anything cool with this app, please send me a link!

Sonograph of a fractal sound.