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

Composer, electronic musician, improviser

## Experimental Musical Instrument Workshop @ MakeHaven

I am pleased to announce another experimental musical instrument workshop in New Haven, this time at MakeHaven (266 State Street New Haven CT.)  The event page is below.  From there you can RSVP if you are interested in coming!

http://www.makehaven.org/event/experimental-musical-instrument-workshop-part-i

Just in case you’re still not sold on the idea of whacky musical instruments, here’s a video of me “performing” on an Udderbot that I made at work today.

Filed under: Current Projects, El MuCo, Miscellany, Music, Phase 1

## 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 ## Scott gets a Marxophone Marxist-phone-what? Heather’s parents got me a gen-u-ayn Marxophone (a fretless zither!) for my birthday. (Thanks Jim and Karen!) Imagine my surprise when they showed up with several boxes of fantastic electronic toys to dissect, the culmination of which was this fantastic instrument. (I might add, I had never heard of nor seen one of these in my life!) While it doesn’t plug in, this instrument has a lot to like. I don’t know if it is the “invention of the century” as it was touted to be in the early 1900s, but it makes some really neat noises! Now before you Tea Party faithful start commenting on the destruction of the American way of life at the hands of Marxophonists like myself, I assure you this instrument has nothing to do with THAT Marx, nor is the instrument itself a socialist (see picture of american bald eagle with flag below.) We will leave the owner out of this discussion for now… From the “Marxophone Homepage:” The Marxophone was produced by the Marxochime Colony of New Troy, Michigan which was in business from about 1927 to 1972. Henry Charles Marx (1875-1947), the founder of the company, oversaw the production of the Marxophone. Marxophones were also produced earlier by the International Musical Corporation of Hoboken, New Jersey under 1912 Patent #1044553. My instrument lived for a very long time in a box in someones attic, so it was extraordinarily dusty and out-of-tune when I got it: just the way I like it! There’s nothing better than the “sands of time” method of tuning for curing what ails you (*$&%# equal temperament!)  You can see the instrument demonstrated on youtube (like everything else) so I won’t launch into a lengthy description of how the instrument is constructed and played.  However, I will post some picture details of the instrument itself along with some audio.

Below is the setup I used to record the marxophone.  The only thing missing is the Shure SM58 microphone that was resting over the instrument on the mixer.  This has become my favorite setup**: cheesy Dell D620 with PureDyne Linux using qjack and Ardour to record, and Audacity to edit; Behringer 1204FX mixer with USB AD/DA converter; Shure (mentioned above); and of course my trusty and stylish Panasonic headphones.  You can see the “Marxophone” plate which is supposed to be used to hold music cards.  Beneath this is a row of metal hammers on flexible metal arms.  When depressed and held, the flexibility causes the hammer to repeated strike the string in a sort of mandolinesque fashion.

Below is the chord tuning indication sticker below the leftmost 16 strings.  This sticker indicates the tuning of the four-string chords, C-G and F major triads and a D7 to round it out.  Note that the lowest note of the “G” chord is incorrectly notated as an A on the sticker even though it says “G” directly beneath it.  Awesome!  Also awesome is the chord spacing, the D7 especially.  Someone would have failed freshman theory…

And finally, here is a closeup of the American eagle emblem above the sound hole.  America loves Marx!

Finally, here is what you have been waiting for, some sound!  This recording is the instrument as I received it, tuned by countless years in an attic, and played in as normal a fashion as was able.

With the mic resting only centimeters above the instrument and directly behind the hammer apparatus, I was able to capture the fantastic mechanistic sound of the levers in action.  If you are like me, this sound is much more interesting than the typical hammer-on-string sound.

And finally, the instrument as it was intended to sound by Marx himself… or at least close.  It took 11 minutes to get to the point that this recording comes in: 1 chord “tuned” and 4 notes of a hexachord almost up to snuff.  I continue to attempt to tune the instrument, but by the time I get the G and A in tune, the C, D and E are fantastically flat.  I probably should have put a warning on this post for persons with perfect pitch…

_

** I have several Macbook Pros laying around with a MOTU traveler among other interfaces at my disposal.  The idea, though, of making great recordings/music with hardware that totals around $350 bucks and contains no proprietary software really tickles my… fancy. Perhaps this all smacks of communist propaganda (again!) but working on-the-cheap gives me a warm feeling inside: it’s nice to know I don’t have to drop$4,000 on gear and software to make art.  I plan to post about this in the future.

Filed under: Current Projects, Miscellany, Phase 1

## Mixer Feedback Music: 1204FX Improvisation 2

### WARNING:

(every good post should begin with one!)

Following any of the steps below to create feedback loops with mixers can harm your gear and more detrimentally, your ears.  The results are often unpredictable and almost always extremely loud.  The pulse waves created by these kinds of setups and heard in the recording below are very hard on the ear mechanism (as you will be able to tell by listening.)  Please take all precautions to limit the amplitude of your speakers and, if listening on headphones, to start with the volume very low and turn it up as needed.  If you plan to attempt the following setup or one like it, start with all volumes at the minimum and raise them once you know what your results are going to be.

Note: the piece begins very quietly, the first loud sound is around 1:26.

The following is a list of equipment used in the above improvisation.

• Dell Latitude D620 (1.6gHz, 1GB RAM) running the latest PureDyne distribution
• Jack and Ardour to record the improvisation
• Behringer XENYX1204FX mixer for all sound generation
• 4 1/4 TS cables
• 4 RCA cables

Kane recently played a few recordings for me of experiments he had done with feedback systems created using his 1204 mixer.  The sounds were appealing and I thought it would be fun to see what it was like to make music with only a mixer for an instrument.  My 1204FX has on-board DSP that Kane’s model does not.  Normally, I do not use the processor at all, but for this exercise it was useful in adding variation to the signal flow and achieving a variety of sonic results.

Last night I experimented for about 2 hours with different routing schemes and to get used to controlling the mixer as a sound-generator.  I recorded 8-10 tests and ended up with about 45 minutes of pretty good material which I may use at some point in the future.  I then recorded 1204-10-29 in one take, using only the 2-channel output from the mixer.  There is no additional material in the recording, nor any post-processing aside from normalization.  The following is the routing recipe I used.

### Routing the 1204FX

The first pair of feedback loops was connected as follows:

Alt 3 output –> channel 1 input (trim at +60) –> sent to Alt 3-4
Alt 4 output –> channel 2 input (trim at +60) –> sent to Alt 3-4

The second pair of loops was connected like so:

Aux Send 2 –> channel 5/6 L (+4) –> Main Mix (no Alt 3-4) –> Aux Sends 1-2 alternately as desired
Aux Send 1 –> channel 7/8 R (+4) –> Main Mix (no Alt 3-4) –> Aux Sends 1-2 alternately as desired

Aux Sends 1-2 at +15
Aux Returns at +5 to +10
Aux Return 1 to Aux Send 1 at +5

The reverberation heard is the built-in “Chapel” reverberation, program 19 on the mixer.  I used the Control Room R & L output channels to route the audio to my laptop for recording.  I monitored the sound using the headphone jack on the mixer with the volume as near to zero as I could get it.  (At some points this was not enough and I had to quickly pull the phones off.)

### Useful parameters for making music

There are many ways to achieve sonic variation within the mixer.  The controls I used were the “pre” buttons for each channel, which control signal flow to the main mix and the aux sends, the faders for each channel plus the ALT 3-4 and Main Mix stereo faders, the “ALT 3-4” buttons, the AUX 1-2 faders, the pan controls, and the 3-band EQ for each channel.  (Is that everything, you say?  Almost, I didn’t touch the trims, the low cuts, or the aux send knobs below the DSP area.)  The controls I used the most were the volume faders and the 3-band EQs.  All of the frequency variation (thumping lows to screaming frequencies around 12k) was accomplished by turning down two of the three EQ bands, and playing with the remaining band while simultaneously working the volume fader for that channel.

If you are interested in experimenting with a mixer like this, trial and error will be your best guide.  Try making the channel settings similar for all channels and then changing them one by one to clearly hear the results.  Or try using only 1 or 2 of the channels and later adding the rest one by one.  Most of all, play with the levels a lot: I noticed that in several instances minute changes to a single channel produced startling results.  Also get to know your routing: changing the ALT 3-4 stereo faders will affect all of the channels using the ALT 3-4 pair, while playing with the gain of an individual channel will only affect other channels that share its signal path.  By bypassing the aux sends (the DSP) you can have two layers of sound, one processed and the other dry (you can hear this clearly in my piece), so experiment with foreground and background layers.

Here, again, for your edification is my improvisation… I know you don’t want to scroll all the way back to the top of the page.

Filed under: Phase 1, Music, Current Projects

## Analog Ring Modulation Circuit

Above is a video and below are some pictures of a simple ring mod circuit I whipped up last night. The circuit is the classic circuit, and I’m simply running two oscillators from a hex schmidt 6-oscillator IC through the circuit as the carrier and modulator. The frequencies of the hex schmidt are being controlled by a PSR (photosensitive resistor) and an FSR (force sensing resistor) respectively. The video shows fairly well how the PSR reacts to the light. The function of the FSR is a little less clear visually, but you can hear it pretty plainly. I can throw up (!) a schematic of the circuit if anyone is interested, but you should be able to find one by doing a google search.

The project requires a 5V power source (batteries only!) a bread board or project board, some wire (i prefer solid-core) two diodes, two capacitors (0.1uf), 1 133k (or thereabouts) resistor, one PSR, one FSR, one hex schmitt oscillator (mm74c14n) and an audio cable or female 1/8 audio jack to run into a) an amplifier, b) a mixer, or c) your computer.  In this case I have two alligator clips attached to the cut-off and split end of a 1/8 audio cable, the other end of which is running into a mixer and then out to small speakers.

Next on the agenda I think I’m going to build me an ADSR for it. This site has a really great page on ADSRs with diagrams, circuit board patterns, etc.

Filed under: Current Projects, Miscellany, Phase 1

## MuCo and the Laying-on of Hands (and pincers)

Having purchased 9 electronic children’s toys for the purposes of evil (and paying by the pound \$16 total!) Kane and Dusty set out to bend the devices to their will.  With the laying-on of hands, ordinary became extraordinary.  Following are some pics and a sound clip of the newly “fantastified” PC Picture Phone.

The cracked-open picture phone.

Alligator clips running from the circuit to a resistor.

Blue marker on the circuit to show the appropriate timing solder points.

Circuit with clips attached to increase speed of synthesis/playback.

Kane testing resistance.

Dusty doing his Kane impression... note gnarled forehead (?!?)

Filed under: Current Projects, El MuCo

## El MuCo: Meeting Notes and Current Plan of Action

Members of El MuCo:

The intricately lain plans of this evening are here reproduced in all their glory.

But, for those who could not make the meeting, some interpretation may be necessary. Here follows some of the decisions arrived at in tonight’s meeting.

1) We’ve settled on a server-client model where the server is stupid rather than attempting to program intelligence: it will basically be a glorified router of sorts.  This is in accordance with our agreement that the first version of the system should be as simple as possible.

2) The server will connect each individual to each other.  Each individual is responsible for creating an interactive instrument that responds to specific OSC messages.  The individual is autonomous and is responsible for creating his/her own instrument. The instrument can be anything, but must incorporate the following key-value pairs (received via OSC messaging) in some way.

\tr: 0 or 1

\float: 0.0-1.0

\int: 20-16k

\arrayF: 16 indexes (elements) each a float with a range of 0.0-1.0

\arrayI: 16 indexes (elements) each an int from 0-11

\string: a string (“ElMuCoRules”) with no white spaces — A-Z only

The messaging system will be of type ‘broadcast’: the individual will select from whom they will accept messages.  (The messages sent by the individual will be available to all, but must be selected by the other individuals.)

The exact nature of the server has yet to be ironed out.  I will post with progress on the server model, code, questions, polls, etc.  If I’ve left anything out, please post a comment.

Our next meeting is scheduled for Saturday January 24th, 2008 at 1pm.  (The Kling’s Birthday!  Happy future birthday The Kling!)

Filed under: Current Projects, El MuCo

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Art of Fritz Horstman
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Music of Matt Sargeant
Art of Heather Strycharz
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Handmade instruments by Scott Petersen and Brian Kane at Artspace New Haven