Vector Synthesis: an Investigation into Sound-Modulated Light
Performing with Voltage and Vectors
The Vector Synthesis project is an audiovisual, computational art project using entirely analog synthesis and vector graphics display techniques to investigate the direct relationship between sound+image. It can be presented as a live performance or a generative installation. Driven by the waveforms of an analog synthesizer, the vertical and horizontal movements of a single beam of light trace shapes, points and curves with infinite resolution, opening a hypnotic window into the process by which the performed sound is created. The term “vector synthesis” refers to the synthesis of analog vector graphics and accompanying audio, and should not be confused with waveform-mixing sound synthesis technique introduced by Sequential Circuits in 1986.
Technically, the work is based on the well-known principle of Lissajous figures, which are a mathematical representation of complex harmonic motion. Originally displayed by reflecting light between mirrors attached to a pair of vibrating tuning forks, we are most used to seeing them on the screen of an oscilloscope, where they can be produced using pairs of electronic oscillators tuned to specific ratios. A 1:1 ratio can produce a line, circle, rectangle or square, depending on the waveform and phase of the oscillators being used. A 1:2 ratio produces a figure with two lobes, a 1:3 ratio produces a figure with three lobes, and so on. By connecting the same signals to a loudspeaker, and seeing hearing the same signal at once, one can draw a direct correlation between the shapes of the figures and the musical harmonics. Interestingly, Lissajous figures are also used in high-end audio equipment to monitor the phase relationship between the two channels of a stereo signal–an important step in mastering for vinyl record production.
The most important piece of equipment in this setup is the Cathode Ray Tube. One’s relationship to the venerable CRT depends very much on their age. So many of us grew up with one constantly around in the form of a television set, while the younger generation live in an era where these objects are rapidly realizing their manifest destiny as e-waste. Unlike modern flatscreens, CRTs draw their image with a single beam of light shot from an electron gun at the back of the tube against a phosphorescent film inside the front of the tube, which gives them their unique visual characteristic.
Conventional video images are said to be raster scanned, i.e. they have been quantized to a grid of horizontal scan lines traced by this light beam, so that the image you see is drawn one line at a time by a left-to-right motion combined with variations in the intensity of the beam. In contrast to this, the light beam of an oscilloscope or vector monitor (such as the one I use) can freely move horizontally or vertically at tremendous speed responding directly the the amount of electrical voltage sent to control it, and is limitless rather than constrained in its resolution.
My main vector monitor has four inputs to control it’s light beam: the horizontal axis, the vertical axis, a pulse-marker (a momentary adjustment of the vertical movement) and the z axis (a momentary adjustment of the brightness of the beam). Other CRTs I use (hacked security camera monitors and 1980’s vector-graphics video game consoles) have at least the horizontal and vertical controls, and often some way to control the brightness as well–which is important as brightness provides one of the key depth-illusions to the image. For these controls I have built a DC (direct current) voltage mixer which allows me to combine up to four analog signals to each of the monitor’s inputs, control the individual and overall levels of those signals, and add an offset voltage if necessary to move the entire image up and down or left and right. Other manipulations are possible using quadrature oscillators and four-quadrant multipliers.
The source of the signals I use to control the shape of the image, as well as what is heard through the loudspeakers, is an analog synthesizer known as the Benjolin. The Benjolin is a standalone synthesizer designed by Rob Hordijk from the Netherlands. It contains two voltage controlled oscillators, a voltage controlled filter and a circuit called a “Rungler”, which allows chaotic cross-modulation possibilities between the different parts of the circuit. Hordijk refers to the Benjolin as a circuit which has been “bent by design”. I have been working with this instrument for several years now, both performing with it regularly as well as building expanded and customized versions of it for myself and other artists.
My live performances and studio setups so far have involved three of these Benjolins, the DC mixer and the vector monitor. The primary triangle waveforms of two of the Benjolins provides the basic Lissajous shape, and the wide range of other outputs from all three can be used to modulate this shape as well as other parameters of the the sound synthesis. The outputs of the three instruments pass through the voltage controlled filter, as well as some outboard effects such as reverb, delay and distortion, which allow me to shape the sound beyond what you would hear from the raw waveforms only. Still, a very direct relationship between image and sound is preserved, even if it is not as literal as left channel=horizontal and right channel=vertical (as you may observe with other artists making what is known as Oscilloscope Music).
The chaotic synthesizers, audio and DC mixers and the effects give me what I want most as a performer–a wide palette of non-deterministic tendencies with which to improvise, and which can constantly surprise me even if I have been working with them for years. Future plans for the project include experiments with laser projectors as well as the construction of handmade CRT objects which can function as sound and light sculptures and installations. Digital recording and projection of the CRT vector graphics has so far been the most frustrating element, as it has been impossible to reproduce the depth, movement and details I see on the screen with any camera available to me.
One could sum up the main benefits of working with analog vector graphics for abstract audiovisual synthesis as follows:
I would like to explicitly point out that there is nothing new about this process, although I would not necessarily consider that a problem. Think of how many novel controllers, interfaces, and instruments are abandoned precisely at the moment when their newness wears off, and long before any sort of virtuosity can manifest itself. (Michel Waisvisz’s The Hands being a classic example to the contrary, it was an instrument where–from a certain point–technological development was consciously minimized in order to maximize the process of developing a performing language with it.) Artists and scientists have explored the use of Lissajous patterns and other mathematically-derived patterns (take the work of Ernst Chladni, for example) long before there were analog computers, voltage controlled synthesizers, cathode ray tubes, or lasers. And once all these elements were in place, there is a wealth of such experiments from the 1950s onward by major figure such as Mary Ellen Bute, Nam June Paik, Ben Laposky, and Steina & Woody Vasulka for the curious eye and ear to explore.
However, I also strongly believe that techniques and technology take on a radically different context once the move from the realm of cutting edge or contemporary to the status of abandoned, outdated, or obsolete. In the past decade, the Cathode Ray Tube has reached this status of what Garnet Hertz and Jussi Parikka call “zombie media”–a commercially-buried format resurrected by willful misuse and creative experimentation. The current vogue of analog sound and video synthesis has produced a new generation of artists working with Lissajous patterns, vector graphics and Oscilloscope Music, and I would count among my peers James Connolly and Kyle Evans (as Cracked Ray Tube), Jerobeam Fenderson, Benton C. Bainbridge, and a whole community of intrepid synthesists on the Video Circuits forum in these adventures.
Utopias and Dystopias in Media Archaeology
Vector Synthesis is the third project I have untaken with a reference to the discourse of media archaeology, and the second which explores the relationship of electronic sound and light. The first project in the media archaeology series, Tonewheels (2007-14), drew on the early 20th-century technology of optical film soundtracks. Inspired by some of the pioneering 20th Century electronic music instruments such as the ANS Synthesizer (Evgeny Murzin, USSR 1937-57), the Light-Tone Organ (Edwin Emil Welte, DE 1936) and the Oramics system (Daphne Oram, UK 1957-62), I developed electronic and graphical systems for modulating sound with light on the overhead projector.
The second media archaeology work, Delilah Too, proposed a model of voice encryption based on the voice scrambling capabilities of the vocoder, a device far better known for its role in the history of electronic music than for its cryptologic potential. While this work did not involve any light-based processes, it did give me the opportunity to dive into texts related to this discourse more deeply, in particular the writings of Friedrich Kittler.
In this media archaeological context, it is important to point out the the history of electronic sound is more than one hundred years old, and since nearly the beginning it has been linked with light–either as accompaniment to the century of cinema which closely followed it, or actually using the optical sound reproduction technology of cinema directly as a means of creating abstract or performer-less sound.
Throughout these more-than-a-hundred years, the goals and utopias of electronic sound has changed little. We still aspire to either to imitate existing instruments, to synthesize previously unheard sounds, or to realize complex works without need of an orchestra. Likewise the dystopias have also changed little. Electronic sound remains a clumsy approximation of acoustic sounds, it still employs alienating, cold, un-emotive timbres and tones, and there still remains a fundamental disconnection between the source of the sound and what is heard. This on top of the fact that, as Kittler writes, “the entertainment industry is, in every conceivable sense of the word, an abuse of army equipment.”
Vector Synthesis also references the long history of pre-digital computing, where calculations were made by connecting the various analog signal generators and processors of massive, patchable systems, and where results were displayed as graphs and functions on a CRT monitor. One of the first practical applications of the analog computer was in controlling the trajectories of German V2 rockets as they traced their rainbow of gravity from Flanders towards London during the Second World War. And as Kittler observed, the relationship of media technology to military tools of destruction was sealed by moments such as these.
Post-war developments continued in this direction. Tennis for Two, a proto-Pong game programmed in 1958 by William Higinbotham on an analog computer at Brookhaven National Laboratories in Long Island NY USA, used an oscilloscope as the display. The laboratory itself performed government research into nuclear physics, energy technology, and national security. Indeed, as Bej Edwards writes, some of the earliest computer art–a vector representation of a Vargas pinup girl–was created by anonymous IBM engineers as a test-screen for the SAGE (Semi-Automatic Ground Environment) defense computer of the US Air Force in the late 1950s.
In the early 1960’s, Don Buchla redesigned the existing function generators of analog computers to respond to voltage controls of their frequency and amplitude. This gave birth to the patchable, analog modular synthesizer which was subsequently expanded by others such as Bob Moog and Serge Tcherepnin. I think of this often when patch-programming my own modular systems, remembering that the signals I am creating are just as much mathematical expressions as they are movements of speakers or flashes of light.
Vector graphics were widely adopted by video game manufacturers in the late 1970’s. Perhaps the most iconic of these games is Asteroids, a space shooter released by Atari in 1979. Battle Zone (1980), Tempest (1981), and Star Wars (1983) all stand as other notable examples, and also as rudimentary training tools for the future e-warriors who would remotely guide missiles into Iraqi bunkers at the start of the next decade.
My own personal interest in analog vector graphics isn’t merely retro-for-retro’s-sake. Rather, it is an exploration of a once-current and now discarded technology linked with these specific utopias and dystopias from another time. The fact that many aspects of our current utopian aspirations (and dystopian anxieties!) remain largely unchanged since the dawn of the electronic era indicates to me that seeking to satisfy them with ideas of new-ness and technological progress alone is quite problematic. Or as Rick Prelinger puts it, “the ideology of originality is arrogant and wasteful.” Therefore, an investigation into tried-and-failed methods from the past casts our current attempts and struggles in a new kind of light.
–Derek Holzer, Helsinki, February 2017
–This text was produced for eContact! 19.3: Light & Sound
03.2017 – Ääniaalto, Vapaan Taiteen Tila, Helsinki FI
02.2017 – Aalto University Media Lab, Espoo FI
01.2017 – Third Space Gallery, Helsinki FI
01.2017 – De Player, Rotterdam NL
12.2015 – Spektrum, Berlin DE
10.2015 – Signal Culture Toolmaker Residency, Owego NY USA
Edwards, Benj. “The Never-Before-Told Story of the World’s First Computer Art (It’s a Sexy Dame)”. The Atlantic, JAN 2013. http://www.theatlantic.com/technology/archive/2013/01/the-never-before-told-story-of-the-worlds-first-computer-art-its-a-sexy-dame/267439/
Hertz, Garnet; Parikka, Jussi. “Zombie Media: Circuit Bending Media Archaeology into an Art Method”. Leonardo, Volume 45, No. 5, 2012, pp 424-430. http://mediaarchaeologylab.com/wp-content/uploads/2013/06/Zombie-media.pdf
Hordijk, Rob. “The Blippoo Box: A Chaotic Electronic Music Instrument, Bent by Design”. Leonardo Music Journal, Volume 19, 2009, pp. 35-43.
Kittler, Friedrich. Gramophone Film Typewriter, Stanford University Press. 1999.
LZX Industries. “Frequency Ranges”. Accessed on 15.02.17 https://www.lzxindustries.net/system/video-synchronization/
Prelinger, Rick. “On the Virtues of Preexisting Material”, 2007. Revised in: Contents Issue # 5, JAN-APR 2013, http://contentsmagazine.com/articles/on-the-virtues-of-preexisting-material/
Torre, Giuseppe; Andersen, Kristina; Baldé, Frank. “The Hands: The Making of a Digital Musical Instrument”. Computer Music Journal, 40:2, Summer 2016, pp. 22-34.