…life under hylaster

I’ve spent a lot of time with the modular synth lately. Here’s something I came up with a couple days ago when I was still stuck at home with the flu. I was trying to see how many parameters could be made to behave in a self-generative way, or according to the machine’s own logic. So the gate on the VCA, the pitch and intermodulation of the oscillators, and the resonance on the filter are all controlled or triggered in some way by randomly-generated info coming from a Sample and Hold/Noise module. Another way of explaining it is to say that noise (a random signal) is periodically sampled and spit back out into several parameters at a rate which is itself determined by the random signal. Not exactly scientific and it all behaves within a limited range, but still interesting to sit back and listen to what the synth makes of it. At the same time - and purely for the hell of it - I was playing a recording of African drum music (Babatunde Olatunji) into the filter CV. So the drum sounds you hear aren’t triggering anything, just getting caught up and tossed around in the chaos. I’m tweaking some along the way but it’s mostly the machine playing itself.
In other news, it looks like I’ll start an MFA in electronic music program at Mills College starting next fall.

Filed by chuck j at 1:35 pm under sounds, synthesizer, works-in-progress
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I’ve been flu-stricken and confined to my house for four days now. In that time I’ve watched two Yimou Zhang epics (Hero and House of Flying Daggers), some global warming docs (Inconvenient Truth and Who Killed the Electric Car), Mike Judge’s Idiocracy, A Scanner Darkly, caught up on recent episodes of House and Rome, and read a lot. I’ve consumed several gallons of hot and cold liquids and soup, blown my nose hundreds of times and coughed up some green stuff. Being too sick to leave my house is now officially getting old and I’m starting feel a bit like Howard Hughes. The early spring onset of carpenter ant activity in my kitchen isn’t helping. So before I slide into full-fledged boredom-fueled dementia and insect-OCD, I thought I’d document some of what has come out of this involuntary alone time.

Remember the Comparsa? I discovered a nifty new use for it: providing control voltage for my little modular synth. Turns out the Comparsa’s output is hot enough to be used as a controller, which isn’t surprising given that the 4093 chip peaks at 9 volts. So those rhythmic thumps and chirps heard in its direct audio output can act like a sequencer or FM source for an oscillator. The results are much more interesting than the direct output.

I was delirious with fever when I recorded these and don’t remember all the details for each track. But the basic setup was the Comparsa into various CV inputs on the modular, then a straight VCA output or ring mod output into a mixer. There was a noise swash (dark box with knobs to the left of the Comparsa in the photo above) in the aux loop of the mixer for adding a little fizz, so you might hear some of that as well:

cascading patterns and more chaotic, industrial-sounding patterns (both feature the Comparsa driving two cross-modded oscillators, I think)

fat bassline (Comparsa controlling a self-oscillating filter)

Filed by chuck j at 1:55 pm under handmade electronics, sounds, synthesizer, works-in-progress
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Continuing with the February projects thread, here is a Max/MSP instrument I made for performing and composing pieces for harmonically-tuned sine waves - like the piece “Stalwart cercle, wavering canton” on my portfolio page. This patch is comprised of a bank of 32 sine wave oscillators. Each oscillator is represented by a track on the mixer-like interface show above.

At the bottom of each channel is a field in which I can enter a ratio to tune the oscillator for that track, as well as number indicating the resulting frequency. The fundamental frequency can be entered numerically at the top left or selected from the keyboard at the top. Behind the scenes the patch is doing a simple math equation for each interval. If for example I make the fundamental frequency 100Hz and I enter the ratio 3:2 (a perfect fifth) in one of the channels, then the interval calculator subpatch for that channel will take 100Hz and multiply it by 3 divided by 2 (or 1.5) and the oscillator will be tuned to 150Hz. And when I have a set of 32 ratios that I like I can save it as a preset. This patch is configured to be controlled with an Evolution UC-33 USB fader/knob controller, and this allows me to actually “play” the patch. It can also run indefinitely for installations. I would like to add automation features for composing, and maybe figure out a more efficient way to do the math.

Here is a piece I recorded using the tuning from Michael Harrison’s just intonation piano piece “Revelation,” which uses some exotic ratios such as 729:512 and 189:128.

Filed by chuck j at 4:22 pm under sounds, works-in-progress
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With five(!) grad school application deadlines behind me and the Rocaterrania film project on hold, the past few weeks have afforded me a little time for some projects that I have been putting off. So I thought I would try to document what I’ve been up to.

Hopefully the cute dog pic from March 4 softened you up for this, because unless you are interested in DIY electronic music, just intonation or audio programming software, this probably won’t be your thing. You have been warned…

So the projects I’ve been bumbling through are mostly open source in nature and fall roughly into three categories: 1- DIY hardware for electronic music (i.e. - standalone hardware instruments) 2 - experiments in the the media programming environment Max/MSP, and 3 - new hardware interfaces for controlling audio software (sort of combining categories 1 and 2, if you will.)

So, first up (from Category 1) we have a device that actually only took a few hours to put together after several days of experimentation and tweaking. I like to call it “Comparsa,” both in recognition of Carnival season as well as it’s endearing ability to make polyrhythmic thumps and chirps. This is what it looks like now:

And here are the incarnations it has gone through to get there:

…earliest breadboard version

… and the “temperamental” perfboard period.

Once I found the right configuration of parts in terms of component values and whether it sounded better to have certain components in series or parallel, it was just a matter of retrofitting some old stereo knobs, drilling holes in the box (recycled drill bit case) and slapping it all together.

Comparsa is a variation on a very simple circuit found in Nicolas Collins’ book Handmade Electronic Music. Two chips, four variable resistor pots, three capacitors, three switches, and a couple of diodes. Basically it’s a CMOS Quad NAND Gate Schmmitt Trigger (CD4093) chip oscillating and modulating itself followed a CMOS Binary Counter/Divider (CD4040) adding some more fun. When the main oscillator is tuned low enough to create a beat the following switchable stages chop it up and add new layers to create hypnotic little patterns.

Here is a sample that starts with an audio-range drone with some frequency modulation from a second stage in the inverter chip and amplitude modulation (tremolo) caused by the binary divider chip (like a VERY low octave effect - in this case so low it that acts as an LFO modulator on the drone). Then the main oscillator is turned way down and we go through a series of rhythmic patterns. Cute, isn’t it?

I highly recommend Collins’ book. I’ve been reading it for months and have played around with some of the projects, but this is the first one I liked enough to actually put in a case. His circuit designs are easy and can be pretty quick if you have some basic soldering skills and don’t try to re-invent the wheel. It’s also a good introduction to circuit bending and hardware hacking if that’s more your style.

These guys have some similar circuit designs (note that they are “copyleft”) although they seem to favor 555 chips. They are also big proponents of the open source Arduino platform for using sensor interfaces to control noises from a computer (and other physical computing uses). I’ve been experimenting with an Arduino lately as well, and I’ll show you the results soon….

Filed by chuck j at 2:10 pm under handmade electronics, sounds, synthesizer, works-in-progress
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Congratulations to our friend Loseractor, who last Friday clocked out for the final time at his Depressing Day Job and will soon be starting a new career with a Dream Job. Read his hilarious farewell memo to his co-workers.

Filed by chuck j at 1:23 pm under nothing much
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