Chrysalis from Chico MacMurtrie / ARW on Vimeo.
For the past few months, I’ve been busy with the electronics and programming of Chico MacMurtrie/ Amprphic Robot Works’ latest kinetic sculpture, Chrysalis.
This is a pedal that I made to control the motor speed of the fans in a vibraphone. It’s designed to fit any Musser frame’s motor and pivots side-to-side so that the player’s full weight is supported, leaving the other foot to press the sustain pedal. The fans move slower when turned to the left, faster to the right, freeing both hands to play as the vibrato is increased or decreased.
Just Completed: A Blue Coral Chandelier by Stephen Antonson. I did the 156 clear-white LED array inside.
A radio piece by Benjamen Walker I recently mixed for the BBC (streaming/download)
A track on which I played percussion with Nettle last February has been released on this new Rebetika compliation from Soundeyet.
is a suite of free audio software that I designed and developed with DJ/Rupture and Rosten Woo dedicated to exploring non-western & poetic notions of sound in interaction with alternative interfaces. This video shows them in action. For more info and free download, is.gd/sufiplugins We are working on porting these devices to the VST plugin format and will be setting to work on a piece of Sufi Hardware in the near future.
I began performing with close-mic’d frame drums many years ago and the microphone that I developed as my solution to this considerable problem has evolved into a product that I’m currently manufacturing selling here in Brooklyn, NY.
I’ll be playing the drums for this, a live through-playing of Brian Eno’s brilliant 1974 album Here Come the Warm Jets.
Helping my friend Benjamen Walker produce his new freeform radio talk show on WFMU, Too Much Information
Electronics, Design, Firmware, Software
Developed in collaboration with Olafur Elaisson and his studio in Berlin and exhibited at Tanya Bonakdar Gallery, this machine ‘listens’ to two electro-magnetic transducers on either side of a divided string and uses these pitches to drive two phase-locked sine wave oscillators (transposed 12 octaves lower) which regulate the AC voltage across the voice coil actuators pushing and pulling the intersecting arms holding the pen on an X and Y axis while a disc holding the paper slowly rotates and travels from one side of the table to the other. The ratios generated by the divided string allow the user to extrude Lissajous curves in a continuous spiral. In addition to the paper drawing, all drawings are recorded to hard disk and can be played back later, for multiple editions of a single drawing.
This video is of the machine in the installation (well, ‘video mode’ on my handheld point-and-shoot camera).
Here’s a screenshot of the mute and fader automation software I developed for James Murphy’s Oram console (with a master section by Purple Audio) at DFA’s Plantain Recording House. This stand-alone Automation sequencer gets it’s sample-accurate sync information from Logic, Pro Tools, or any supported audio sequencer via ReWire. The sample count provided by ReWire is downsampled (according to the sample rate of the session) to 30 frames per second and a serial count of these integers provides the timeline on which events are recorded. This sequencer features both a static mode for simple snapshot recall and a dynamic mix mode with read, write, touch, and latch modes for fully automated analog mixing. Recent additions include graphical ‘pencil’ editing and a subgroup/master fader automation trimming.
Steel, Magnets, Wire, electronics Concept, Prototype
After trying and trying to come up with a bow wheel that could maintain effective friction on a surface while isolating the noise of the motor and mechanics from the acoustic resonating chamber, I decided to investigate making an electromagnetic bowing device, like the E-bow. Pictured above is the prototype for such a device. A physical oscillator. There are two coils around AlNiCo (Aluminum Nickel Cobalt alloy) magnetic poles, one a pickup and the other a driver. These are wired to the input and output of an audio amplifier IC and fed back into one another through the spring steel tongue (pictured here with a piezo element under it’s bridge terminating at the 1/4” jack). A digital potentiometer regulates the amount of voltage driving the circuit for dynamic control. Staccato articulation can be achieved by instantly reversing the electrical polarity of the driver to stop the vibration. The gain of the audio amplifier goes quite high, all the way to the 12V rail supplying it and reads as a square wave on a scope even at low gain settings. Because the steel tongue, like a speaker cone in a back-feeding guitar amplifier, is physically unable to jump to the +/- DC poles and has to ‘slide’ to them, a near-perfect sine wave results. With light dampening on various areas of the tongue, partials and overtones can be elicited. By automating changes to the size of the resonator box (an acoustic resonant filter), exciting timbrel variations can be made. An upcoming experiment will be to utilize this same circuit and two piezo elements embedded into a solid piece of hardwood in an attempts to make the wood resonate as the medium for the feedback of the two piezos.
Batucada is a pattern-based percussion sequencer built in Max/MSP and designed for live performance using a PowerBook. Controlled mostly by the ‘qwerty’ keyboard, Batucada allows the performer to improvise with patterns and ‘grow’ new ones live. It features variable-division repeats with the right hand, while the left hand selects the instruments to which the repeats will be applied. Mute and Solo, like repeat are applied with the right hand to instruments selected with the left. Signal-based timeline warping (‘swing’) and offset can be handled either globally or locally, allowing different instruments to have their own swing and/or offset settings. Batucada can run as either a master sync device or can be slaved to incoming MIDI time code, MIDI beat clock, ReWire, or a traditional audio click track. In addition to MIDI note commands, Batucada can send 7 and 14-bit MIDI LFO information as well as 2 +/-5V control voltages for interfacing with analog synthesizers and processors. Within the software, I’ve implemented ‘VeLFOs’ (7-bit scalable triangle/sine/square wave LFOs) synced to each track (with individual offsets) for governing velocity, but this data can be mapped to anything from filter cutoff to event execution probability. Timing is coupled to the sample rate by the scaling of signals and is only subjected to Max’s scheduler when turned into MIDI note messages at the output.
Development of the above pictured MSP version is frozen and I am currently working on a new build of Batucada in Pd
utilizing Pd’s < sample-accurate event scheduling and driven by a clock which will also implement Euclidean GCD/LCM
-based counters for creating rhythmically compelling math-beats. Most all performance functionality that inspired development of Batucada has been eclipsed in recent versions of Live
Digitally Controlled Acoustic Percussion
Concept, design, engineering, prototyping, machining, and programming (firmware and software).
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These are miniature, modular instruments designed to affix to virtually any structure thereby allow the composer musical control of anything from a battery of specially designed instruments to structural surfaces within pre-existing architectural space.
With an emphasis on simplicity, each of these mechanisms’ design usually consists of only one electromechanical actuator (a rotary motor, or linear solenoid) which responds to varying degrees of supply voltage remotely regulated by a microcontroller. This single-actuator design philosophy demands that all mechanical movement within the instrument be subordinated on the physical capabilities of the lone motor or solenoid employed and, while this may sound like a limitation, such use of mechanical design (as opposed to more ‘intelligent’ electronic design) manifests a reliability, mechanical consistency and modularity that would otherwise not be possible.
Each device can be fitted with a variety of harnesses for mounting and is connected to the brain (box containing the PIC microcontroller and DC power supply) via a single run of cable. Thus, the microcontroller administers the appropriate voltage to hit, shake, scrape, bow, spin, whip, or pluck sound from any sonorous object with the exact precision one would expect from digital control.