Close

New video: Shift register techno funk

A project log for DIY Modular Synthesizer

A full-featured modular synthesizer • aka "The Alligator"

chrisbeckstromchrisbeckstrom 09/11/2015 at 12:110 Comments

New video using my synth. Check it out!

More details:

For this track I recorded video while I recorded each part, then edited everything together in Ableton Live. It's certainly a lot of seeing my bearded face, but if you suspend your disbelief it's sort of like a band playing together in my basement.

- Technical stuff -

The track started with a patch on the modular. I clocked a 4-stage shift register with 16th notes from Ableton Live (clicks were generated in a Max for Live clock divider/multiplier I built, then sent to the modular through an audio cable), then sent a non-synced clock into the shift register, which created some cool variations. I took the 4 outputs of the shift register and ran them through an R/2R resistor ladder which then modulated the pitch of a VCO. I was trying to find a way to generate a funky 16th note sequence that didn't exactly repeat– and this does the trick! The only "regular" sequencer I have built so far is 10 steps, so it is limited in terms of loop length. At the beginning of the track only one of the shift register outputs is patched into the R/2R ladder. As I patch the other three, the sequence evolves and gets a bit more complicated.

The lead sound that I play with a keyboard is originally generated in Ableton Live as a square wave. I sent that square wave (via audio) into a 4040 clock divider, which in turn spits out an analog square wave an octave lower. I mixed two octaves to get a more interesting sound. I then patched those squares into a vactrol-controlled resonant low pass filter. Someday I'll build a MIDI to CV module, but for now this is the easiest way to play the modular with a "real" keyboard.

The "hihat" sound is a 40106 CMOS noise module (sort of like the Roland TR-808 cymbal circuit) going through a low pass gate which is modulated by my brand new slope generator (the pink panel module).

The "cowbell" sound is just two square waves through a diode mixer (again, similar to the TR-808 cowbell) patched through the low pass gate, triggered by a manual button.

There's some other stuff going on, but after I disassembled the patches I forgot how I made those sounds. That's what happens when you use a modular! I think one of the sounds was a square wave patched into the slope generator for wave shaping, then patched into a distortion module, then into the low pass filter and the cutoff was modulated by a 9 step sequence. Pretty sure I also modulated the pitch of the oscillator with another oscillator which created those weird sci-fi sounds. In mixing I panned that stuff all over the place which I think sounds pretty cool, maybe a little disconcerting if you're listening on headphones.

There are some feedback-ish sounds that happen, and those are created by feeding the output of a Live plate-ish reverb back into itself.

The drums were recorded with three mics; the bass drum goes into Ableton Live and then through an EQ and gate, which then heads into the modular via audio to trigger the twin-T drum module. Basically the "real" bass drum triggers the synth bass drum, which I think sounds pretty badass.

The other stuff is pretty simple: bass through a tube preamp into Live, saxophone through a Røde NT1-A, the tube pre, then into Live.

All audio went through my analog Mackie mixer on its way into the computer, which I think helps give everything a bit of an analog flavor.

Musically, I'm interested in the intersection of old-school style Detroit techno and 70's-style funk. I happen to think modular synths can be amazingly funky, and I really like the combination of super tight synth lines with loosey goosey drum playing.

Discussions