electronic music synthesizers and oscilloscope

Robert Morris

Program Notes

Lissajous, written in 1971, is a fifteen minute audio visual composition exploring the then infant field of visual synthesis, which was in part the use of electronic music synthesizers to produce visual images with the aid of an oscilloscope. Unlike many other efforts in this area that are either silent or provided with background music, Lissajous employs a stereo tape which is presented simultaneously to the eye and the ear. The electronic signal stored on the tape was generated with the aid of an ARP 2500 electronic music synthesizer. One channel of the tape is sent to the Y axis and the other to the X axis of the scope. At the same time, both channels are sent into the inputs of a ring modulator*, then into a plate or spring type reverberation unit, and finally into a monaural amplifier and speaker system. The reason for the electronic elaboration of the aural aspect of the composition was suggested by the fact that the most elegant and interesting visual patterns are usually derived from electronic signals whose waveforms are too simple and uninteresting when heard; conversely, more complex and often "beautiful" sounds appear garbled and/or incoherent when viewed on the scope. Thus the simple waveforms that are visually satisfying need to be modulated in order to produce the kinds of sounds that are musically viable.

During the composition of the piece I worked in real time with the scope, tape machine, and synthesizer. From the outset it was obvious that even with the aforementioned sound modification some of the really astonishing sounds were hardly as interesting when viewed, and that the sonic counterparts of the undulating and intricate spirals and webs were even ugly to my ears. This led me to conceive of the work as the alternation of visually oriented sections with others that were more sonic in overall appeal. (There are, of course, sections in which both sound and pattern are equally predominant.) I also found that since very subtle timbreal effects are derived from signals that produce much greater visual effect, one becomes quite sensitive to the nature of sound, per se. The phenomena of beats, harmonic spectrum, minute vibrati and tremoli are tremendously heightened when displayed on the scope. As a result, the composition involves an intimate marriage between the eye and the ear and implies some very interesting theories concerning the correspondence between visual and aural sense data.

The form of Lissajous is simply a chain of only somewhat related events in terms of gesture and material. The first section however might be thought of as a "theme" of aural and visual material that undergoes continual transformation during the body of the work. The types of transformation that occur may be abstractly described as the movement between and among phases of continua connecting mutually exclusive poles. Some of these continua are listed below: symmetry/assymetry, clarity/incoherence, figure/ground, movement/stasis, periodicity/aperiodicity, alternation/ continuation, high/low, front/back, large/small, anthropomorphic/abstract, etc. Very often a visual continuum will intersect with an aural continuum in a highly surprising manner.

The composition was completed in the spring of 1971 and realized in the Yale School of Music Electronic Music Studio. The name of the piece derives from the French mathematician who first described the functions of the amplitudes and frequency content of two or more trigonometric variables, and the phase and frequency relationships between them.

In 1972, I wrote:

...if Lissajous "means" anything at all, it is hoped that it will [help] dispel the all too common sentiment that the arts and the technology of science are mutually exclusive. It has always been of interest to me that both the worlds of art and science communicate the knowledge and experience of places where words cannot go. Thus they are alike in that one's response [to both] is a sense of wonder and awe at the hitherto unknown regions within us and without us.

*A ring modulator is an electronic processing device that produces at its output the sums and differences of the frequency components that are sent into its two inputs. It is often used in electronic music to simulate gong, chime, and other percussive sounds.