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the video synthesizer

Below are excerpts from a late 1970's paper by Tom Dewitt describing an enhanced video synthesizer called the "Design Device". This proposal reviews video synthesizers of its day, touching on their principles and limitations in waveform generation, colorizing, signal routing, and image display through XY deflection. The suggested enhancements form a technical sketch, to synthesize a video art tool for use by independent video artists. J.S.

Review of Existing Video Synthesizers and Ideas for a New One

To free the video artist from the confines of the real camera-recorded world, it is necessary to develop instruments which generate a television compatible signal from raw electronics. A synthesizer is the paint and palette of the video artist, a device which lets the artist construct spaces from the dictates of imagination.

The first video synthesizers began to appear almost a decade after the development of complete audio synthesis systems. There are compelling reasons for this delay. The development of a time variant artform is just now being born in the visual arts, centuries after the establishment of a related set of time variant structures in music. Technically, the video synthesizer is more complex than its audio cousin. Video signals cover a frequency spectrum 100 times greater than audio and must be constructed according to a precise timing synchronization which does not exist in the one dimensional audio signal. Consequently, design concepts and instrument components are now coming together for the first time.

There have been two approaches to video synthesizer design: vector graphics and signal intensity. This split is a consequence of the television system itself which uses a one dimensional high frequency signal to describe a two dimensional field of much lower frequency. The systems developed by Steve Rutt and Bill Etra, Computer Image Corp., Vector General, and others operate on the x and y deflection amplifiers of a cathode ray display. The synthesized or processed images coming from these devices are rescanned by a conventional camera for recording on video tape. Synthesizers, on the other hand, such as those developed by Stephen Beck, Dan Sandin, and EMS Ltd., operate on the intensity or z component of the video signal. Their output is made compatible with video standards by a processing amplifier or through a color encoder. The two approaches can be combined in a single device. In fact, Sandin has worked extensively with a computer controlled vector display, and Rutt/Etra synthesizers are invariably teamed with keyers, colorizers and other signal processors. However, no one has come out with an integrated package that incorporates both approaches.

The artist designed synthesizers are "modular", that is, specialized devices are linked by patch cords which are manually inserted to complete a complex program. Modular design is essential in video, because it permits parallel and simultaneous processing of high frequency signals. The chief drawback of the general purpose computer in video synthesis is that it performs one operation at a time and cannot keep up with the video clock. As in the development of the audio synthesizer, engineers have provided artists with functional module building blocks which efficiently accomplish commonly needed functions. Modular design also permits a wide range of interconnections depending on the "patch" made between them. For example, a system of only 8 modules, each with a single input and a single output can be patched in over 40,000 different ways.

While modular systems provide both variety and efficiency, they also can present the artist with a confusing welter of two ended wires which makes live performance difficult and leaves him with no permanent record of his patch. The first step in improving this situation came with the introduction of the matrix switching systems of the Arp and EMS synthesizers, adapted for video by Woody and Steina Vasulka. These systems have manually set crosspoints and permit patchfields to be recorded by graphic notation. Going a step further, Don Buchla and Bell Labs have developed computer controlled patchfields which are notated with a verbal language.



We still haven't located Al Phillips to whom Eric Siegel entrusted his only video synthesizer. In a comparison to electronic audio instruments, there is no comparable historical or intellectual protocol to even consider the video instruments as cultural artifacts. While Paik's first synthesizer is still in the basement of MIT, the first Buchla box has just been purchased from Mills College by a French institution.

It is a real pleasure to lift up a piece of scrap, to dust it off, return its name, restore it, insure it for thousands of dollars and publish it in an Austrian art catalogue!

- Woody Vasulka, Eigenwelt der Apparatewelt, Curatorial Statement, 1992.

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