S C O T T E R I C P E T E R S E N

Composer, electronic musician, improviser

Virtual Matrix Mixer (yes, in SuperCollider)

Screenshot of the Waz Matrix Mixer in action

Kane and I recently dropped $170 at JameCo on potentiometers, switches, diodes, project boards, and more in anticipation of several MuCo projects we have been planning.  The main project now after some op-amp FAIL last night (the FAIL being Mimms’s op-amp.  Yes, there is a free version on the nets.  No, we will not help you torrent it illegally) is a classic 3×3 matrix mixer which we intend to use a la David Tudor to make feedback music of the most splendiforous nature.  As some of you may have noticed, I have been slightly obsessed with feedback of late, and for good reason: feedback, like Frosted Flakes, is better than good, its great.  It’s great to make, great to listen to, great to cover up the drunk, sleeping neighbor’s DVD menu music that runs for hours and hours after he’s passed out on the couch.

I plan to post a little “Fun with Feedback” post this weekend (maybe tomorrow), but I will jump the gun and get to results before I do.  In anticipation of the analogue matrix mixer, I decided to spit in the eye of convention and model an analog (make an analog of…) device digitally first because I wanted to see what my results with the analog device might be.

This was an interesting experiment because it highlighted the reality that, while creating digital analogs of analog equipment may be useful on a basic, conceptual level, it breaks down completely when it comes to the actual implementation/realization of the object.  This may seem obvious to some of you (congratulations), but one wouldn’t suspect this with the tradition of modelling analog equipment in electronic music studios the world over.  Not to mention all of the digital synthesis software that models even its appearance.  (Yes, Reason, I’m looking at you… with disdain.)  I’ll make a long story short and say that approximately 2 minutes after I sat down with idea the matrix mixer in my head to start coding it up, I was conceptually far enough away from the analog instrument that looking at my notes one might not even guess it was supposed to be a simple 3×3 summing mixer.  This is partly because of the nature of programming itself, and partly because of the idiosyncrasies of any programming language.  If one were to mock up the 3×3 in Csound, SuperCollider, and ChucK, it would become very clear very quickly that one cannot think the same way about the same object when coding in different languages.  I now digest.  (yes, digest.)

After some headbanging and with some help from Kane and HJH (on Nabble) the Waz Matrix Mixer V.1 was realized last night.  The SC3 code is below so you can see how it is constructed.  The mixer is simple: it routes 3 input sources (in this case, either the built-in microphone or a sine oscillator) to 3 outputs each.   At the outputs is some processing, a delay line, distortion, etc.  The output from the processing can then be routed back into any of the inputs including itself, thus the feedback.

In the following picture, the blue knobs represent the 3×3 matrix.  Each row routes its respective input to outs 1, 2, and 3 individually.  The red knobs control the input volume, and the yellow knobs control the amount of outs 1, 2, and 3 that are fed back into the chain.

janky gui -- needs work, but works...

As promised, here is the code (provided Scribd ever finishes processing it…)

Here is a recording with the mic as the input source.  I’m not actually doing anything with the mic, I’m just letting it hum and collect room noise and the output from the speaker which is right next to it in the laptop.  The delay line’s delay time parameter is being dynamically changed using the mouse position (x axis) which results in pitch-shifting.  This is responsible for the “glitching.”  Additionally, I am using the mouse position y axis to control the decay time (in seconds.)  When the decay time is over 3, the processing synths begin a sometimes irreversible pattern of self destruction.

Here is a recording of the sine oscillator inputs.  There are three sine tones around 440, 1000, and 1400 Hz respectively.  The rest of the processing is as described in the example above.

Filed under: Code, Current Projects, El MuCo, Music, SC3 - Code - Music - More, , , , , , , , , , ,

Glossary

Glossary of terms often found on the pages of this site
This page will be updated often.

Algorithm: an algorithm is a general rule set (finite) that is used to solve a particular problem.  An algorithm is best when it solves one problem and it does so efficiently, using the smallest number of instructions required to perform its task.

Arduino: [taken from the site] Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It’s intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.

bend: an adjustment made to an existing circuit that alters it in a way audibly perceptible (and awesome.) or that causes functional change (flow of charge, etc.) [WARNING] NEVER attempt to bend an instrument that is plugged into the wall:  AC + metal + you = death.

distortion: distortion may be defined many ways depending on the signal that is being distorted.  Very generally, distortion is the addition of noise to a signal.  Here, noise is defined as anything that is not part of the signal when running under standard conditions.  In other words, distortion occurs when something causes some part of the signal (amplitude, voltage, etc.) to exceed the ability of the conductive medium (component parts, amplifier, speaker) to represent the signal accurately.

hardware hacking/HH/circuit bending: using any means to modify an existing electronic product to create new functionality, either in the motor/physical or sonic domains.

LED: a light emitting diode.  LEDs are in just about every piece of electronics.  Mostly used to let you know if your electronic device is on, they can also be useful for testing circuits.

lick-n-stick: to wet one’s finger with ones saliva (!) and apply it to the circuit in an effort to sniff out bends.  Very useful when attempting to locate the timing circuit; when pitch goes up, you’re on the right track.  [WARNING] as noted ALL OVER the internet and in books, one should never attempt to bend a toy that is plugged into the wall!  AC = death, esp. when you are touching it with your spitty finger.

potentiometer: a variable resistor with a third adjustable terminal. The potential at the third terminal can be adjusted to give any fraction of the potential across the ends of the resistor.

resistor: A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current passing through it in accordance with Ohm’s law: V = IR

sniff out: to look for bends.

SuperCollider: SuperCollider is an audio/visual programming language.  [BIAS] It is vastly superior to all other audio synthesis languages ever written.

Filed under: Phase 1, , , , , , , , , , , , ,

El MuCo: Custom JankoTUne (KidTunes) Post-Evisceration Construction

Once the PC Picture Phone and the KidTUnes were eviscerated and frankensteined back together in a manner more aesthetically pleasing to both eye and ear, it was time to re-house the KidTunes.  The aesthetic of painted toy plastic is nauseating to both Scacinto and Kane so a plexiglass housing with stainless (when possible) hardware was decided upon to both provide working functionality and “playability.”  Additionally, we decided that we didn’t want the re-housed instrument to cover any of the modification or original circuitry, so plexi was the natural choice.

Here are a few pics of the guts of the two instruments, both completely torn from their original housings.

Guts

Guts

Splayed-out PC Picture Phone

Splayed-out PC Picture Phone

Splayed-out PC Picture Phone 2

Splayed-out PC Picture Phone 2

Splayed-out PC Picture Phone 3

Splayed-out PC Picture Phone 3

Here follows the construction of the JankoTUne instrument.  For the project we picked up three pieces of plexiglass (about 12 x 14”), a scoring tool, a few bags of 1” and 1.5” screws with nuts and washers, and two carriage bolts for the touch controls with two nuts and two washers apiece (so connections can be made simply by clamping the wire between the washers.)  Additional tools included a pair of snips, a drill with a number of different sized bits, a piece of scrap lumber, and some MuCo Majicke.  The snips are useful for just about everything from cutting molded plastic housings to metal screws and tiny annoying bits that keep your potentiometer from laying flush against the plexiglass.

This first picture shows the keyboard/main circuit which has been mounted onto the plexiglass with three 1” screws with 1/2” 6-32 spacers (1” spacers we cut in half with the snips.)  In the front, we used two 1” screws with spacers as supports only as there were not mounting holes on the front of the circuit board and we didn’t want to risk drilling them from scratch.  The holes at the back of the board did have to be bored-out a little for the screws to fit without risking cracks.

KidTunes Main Board Mounted

KidTunes Main Board Mounted

KidTunes Main Board Mounted 2

KidTunes Main Board Mounted 2

Next we mounted the switch circuit using the same method as the main board.  The drill bit size for this sort of thing should be, as with other projects, just slightly smaller than the size of the screw.

KidTunes Switches Mounted

KidTunes Switches Mounted

Here is the back of the board showing the first two mounted circuit boards.

KidTunes Underneath

KidTunes Underneath

This shot shows Kane fitting on the potentiometer onto the control panel.  The control panel piece of plexiglass was from the same piece of plexi as the main body.  We scored the glass 3-5 times and it snapped easy-peasy and clean.  The control panel is mounted on with 1.5” screws and 1” spacers with nuts.

KidTunes Mounting Component Panel

KidTunes Mounting Component Panel

KidTunes Mounted Component Panel

KidTunes Mounted Component Panel

Here is the finished control panel with potentiometer, two switches for stacatto and legato (sustain), two 1/8” audio jacks for connecting a speaker and running audio out to a mixer/computer, and the two carriage bolts in the foreground which act as touch controls so we don’t have to fidget with the actual board as much.  The touch controls are really reactive and vary much more than simply touching the wire connections.  Touching the top versus the side, and even moving around the surface all changes the resulting sound.

KidTunes Mounted Component Panel 2

KidTunes Mounted Component Panel 2

KidTunes Mounted Component Panel 3

KidTunes Mounted Component Panel 3

(Kane says: just to give a bit of info on what all the doodads are going to do (from left to right, top to bottom), 1) a megapot which replaced the timing resistor, 2) two mini-jacks for speakers, lines-out, whathaveyou, 3) switches to turn on and off “sustain” mode and “staccato” mode, and 4) two customs touch nodes–aka, the jTouch©, just to get all proprietary and jCapitalist on you–which add extra tastiness to the sound.)

Showing off…

Scacinto with the almost-finished JankoTUne

Scacinto with the almost-finished JankoTUne

JankoTUne Almost Complete

JankoTUne Almost Complete

And now follows a few words of caution for anyone who would attempt a project like this.  First, protective eyewear is your friend.  Working with drills and plexiglass eventually = flying shards of sharp nastiness.  Second, when working the plexiglass, especially smaller pieces which are more likely to snap/crackle/pop, be sure that you support the entire piece of plexi when you are working with it to reduce chance of breakage.  When drilling plexi, use the smallest bit possible and lay the plexi flat on a piece of scrap wood, or two pieces (supporting either side of the drill hole.)  When the bit is too big, the plexi can get caught and chunk or break off around the drill hole.  Go easy on the pressure and high on the speed of the drill — too much pressure and the plexi will a) crack, or b) the bit can gouge chunks out of the board (on the backside of the drill direction.)  As always, patience is a virtue.  Take your time, measure twice, drill once.*

*All of this advice is true and sound: we didn’t take any of it and injury, breakage and sadness abounded!

Filed under: El MuCo, , , , , , , , , , , ,

G O I N G S O N : L O C A L (ISH)

fritz Art of Fritz Horstman
kane Music of Brian Kane
fritz Hartford Phase Shift
fritz Hartford Sound Alliance
Lique Art of Philip Lique
Lique Music of Matt Sargeant
strycharz Art of Heather Strycharz
uncertainty Uncertainty Music Series

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Handmade instruments by Scott Petersen and Brian Kane at Artspace New Haven