…life under hylaster

Here’s one project I’ve managed to complete this semester. For a while I have wanted a tactile controller for my analog setup. As much as I enjoy letting the machine play itself, there are certain situations where it is preferable to have the instrument “shut up” when I’m not touching it (as David Wessel would put it.) This kind of control has been notably absent in situations where I am playing with acoustic musicians.

I was initially inspired by the touch capacitance controllers designed by Don Buchla for his modular synths. Here is one of two Buchla touch controllers we have at Mills:

I like how Buchla’s design doesn’t really have anything to do with a traditional keyboard - this seems logical given how new the electronic instrument paradigm was when Buchla built his first synth in 1964. Buchla’s synthesizers were designed to make experimental electronic music, or live “tape music” as it was called back then. But the Moog approach caught on commercially, and soon people associated synthesizers with piano style keyboards and electronic emulations of acoustic instruments.

Each touch plate is pressure (actually capacitance) sensitive and has adjustable control voltage (cv) range. There is also a sample and hold circuit to “remember” the most recent voltage. I wanted to make something similar, but quickly realized that with today’s sensor technology I could make something with the same functionality and a lot less trouble using force sensing resistors, or FSR’s. James Fei has a small box with FSR’s and I tested James’ controller to make sure this was what I wanted.

I wanted my controller to be compact and easy to play with one hand, with an ergonomic layout of the touch pads. I also wanted a linear potentiometer used in ribbon controllers to supplement the pressure sensors with a different kind of gestural control. I decided that each sensor should have an adjustable cv range like the Buchla, separate cv out, that the two larger touch pads and the ribbon would have individual trigger outputs for opening VCA’s and triggering envelopes, and that there would be a master trigger output. The circuitry is quite simple - 12v comes in, each sensor has a voltage divider to send the variable voltage out, and a LM339 comparator chip is used to process 5v trigger voltage outputs.

Here are some photos of the build process.

Filed by chuck j at 5:57 pm under handmade electronics, synthesizer, works-in-progress
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(appropriated image)

It’s time to catch up on some recent recordings. There hasn’t been much time since school started, but I’ve made it a personal goal to record a synth jam every couple of days.

I posted something similar a few months ago, but I think this one is a bit more refined: Here is a synthesizer pretending to be “Nature.” Noise -> Sample and Hold.

Here is feedback-generated rhythm. Notice how voltage fluctuations throw you off just as you are getting your dance move down.

This one’s namesake is some bad news I received about my car yesterday.

And here are some pieces that resulted from recent course work:

A soundwalk piece (for a seminar with Zeena Parkins.)

And a piece programmed and performed in Supercollider (for a Computer Music seminar with Chris Brown.) This one makes gratuitous use of an object based on Xenakis’ GENDY program that does “dynamic stochastic synthesis.”

“The lab” circa last week:

Filed by chuck j at 1:55 pm under handmade electronics, sounds, synthesizer, works-in-progress
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You heard it here first (and, possibly, last.)

Mahasamatman:
Shannon Morrow (drums, percussion),
Chris Eubank (cello),
Chuck Johnson (electronics, steel guitar)

4-9-07

5-3-07

Filed by chuck j at 4:16 pm under self-promotion, sounds, works-in-progress
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…

Filed by chuck j at 10:32 pm under pagan holidays, sounds, synthesizer, works-in-progress
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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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