Segmod is a non-standard sound synthesis that embraces the discrete nature of digital sound. All sounds created with Segmod result from the concatenation of simple periodic waveforms, such as sine, triangle, and square waves. The sixteen contributing composers have employed a vast array of different compositional, aesthetic, and technological strategies, ranging from inaudible sounds, to neural networks, chaotic functions, careful micro-montages, and analysis-resynthesis techniques. While the results differ widely in sound, all lead back to the idea that synthesis can be seen as a form of composition.


THE SCOPE OF REDUCTION
SIXTEEN COMPOSITIONS REALISED WITH SEGMOD
by Leonie Reineke

In 1969, the composer Jean-Claude Risset published his Bell Lab Catalogue, a series of short pieces that represent an early stage in the development of digital sound synthesis. Risset was interested in demonstrating the array of possibilities offered by sound production with computers at the time – that is, the synthetic simulation of traditional acoustic instruments using technological means. What emerged was a plethora of short and stylistically highly diverse studies, which range somewhere between demo sounds and musical miniatures.

While at the time the accurate approximation of acoustic instruments by means of computer-programmed sound synthesis was central, today – when the achievements of digital technology have already opened up an astronomically large space of possibilities – different ideas have taken centre stage. Martin Lo-renz and Luc Döbereiner don’t seek a sonic mimesis with their project Segmod. Rather, they are interested in a computer-generated music ‘as such’, that is, they focus on the digital as digital. Together they have developed the non-standard synthesis program Segmod, which allows the frequency of each cycle of a sim-ple waveform, such as a sine wave, to be specified. Thus, frequency modulation is not performed continuously (as is the case with FM synthesis) but rather peri-odically or in a ‘segmented’ way. This approach is far removed from any naturally occurring form of vibration. In this sense, the idea of composition, the piecing together of sounds, already takes place on the level of the production of the ma-terial – a music created that can indeed be termed genuinely digital.

However, the form of presentation that has been chosen for Segmod is not dis-similar from the one chosen by Risset. The idea of electronic sound as a cata-logable product can also be discerned in the compilation of works that make up the Segmod project: sixteen composers developed short pieces, which involve different aspects and varieties of the sound synthesis method. Yet despite the strong constraints that Segmod carries with it – having to deal with a single pa-rameter, frequency – an enormous spectrum of different compositional ap-proaches and sonic results has been created, ranging from minimalist rhythmical compositions to virtuosic timbre artistry to purely conceptual works.

For her work tschilpkrr, the sound artist and sound-designer Veronika Klaus worked with a graphical interface, with which she drew the waveforms and pitches of each cycle. Next, she converted these data into text files. Klaus says: ‘I’m interested in the possibilities that emerge from the control over each wave-form cycle. The intermediate sonic stages are especially interesting: with which density does a sequence of individual pitches turn into a single tone? And the other way round: How strongly may the pitches of each period deviate before they turn into noise?’ If one listens to Klaus’s composition with headphones, the sounds create tingling sensations at the roof of the mouth and can thus be per-ceived as an all-around sensual experience. Ji Youn Kang’s work PulSegMod creates a similar effect. The piece opposes two independent rhythmic levels by clearly splitting up sequences and figures of impulses into both stereo channels. This creates a strict dual monophony, which also unfolds its charm when listened to with headphones, especially since the perceived proximity of the sounds cre-ates an almost encroaching intimacy.

In addition to PulSegMod, a number of other pieces in the compilation sound strikingly reduced, clean, and cool, which surely fulfils quite a few criteria of what the term computer music (as opposed to sound production by means of acoustic instruments) refers to. This is also the case with Martin Lorenz’s composition Frequencies III. Here, all the used frequencies are octaves of one another. They are arranged in such a way that the sum of their wavelengths equals the wavelength of the lowest fundamental frequency used. This arrangement gives rise to a rhythmic structure that is indeed danceable, especially since beats repeatedly emerge whose timbre is strongly reminiscent of a bass drum.

A unique feature that is characteristic of working with Segmod is the peculiar re-lation of conception and result. As Luc Döbereiner says: ‘It is less about taking an idea of sound as a starting point and then searching for ways to realise that idea. On the contrary, one conceives of a system for dealing with this modulation procedure and subsequently discovers the sounds that this system can give rise to. I have been especially interested in creating patterns that range from noise to periodicity, that is, from total chaos to total order. I came upon an algorithm called coupled map lattice. It is a mathematical model used to represent behaviours of certain bacteria, air turbulences, and liquid dynamics. The use of a few simple rules can produce extremely complex behaviours creating patterns that play out on different temporal levels.’ Thus, in Döbereiner’s piece Kaneko, different sonic processes, which develop at different rates, can be perceived simultaneously, thus creating a continuum of permanently transforming states. In respect of genre, the piece can almost be classified as noise. This is similar to Lula Romero’s work mtrak and David Pocknee’s Mel. Pocknee, however, doesn’t confine himself to the use of Segmod, but also feeds some sounds through a guitar amplifier, thereby creating an additional level of distortion unfolding in the music.

The material in Hanns Holger Rutz’s Légende also sounds distorted. A reason for this is surely that he works with a sound recording of a human voice that is many-times deconstructed and, via sonic detours, recomposed in the course of the piece. What is particularly fascinating here are the moments in which a quali-tative leap in the listening occurs: when do we merely perceive undefinable nois-es and when does it all turn into the distorted yet recognisable sound of a voice. Rutz himself describes the piece as a ‘study’, which also demonstrates another criterion inherent to music produced with sound synthesis: the inclusion of knowledge from the fields of acoustics and psychoacoustics in the musical fac-ture.

At this point, one can draw another parallel between this compilation and Jean-Claude Risset’s Bell Lab Catalogue, which contains short song-like constructs as well as demonstrations of auditory illusions such as the infinite ‘Risset-Glissando’. Conceptual approaches of this kind can also be found among the pieces in the Segmod compilation: JLIAT’s piece A minute wave contains a single period of a wave with a frequency of one sixtieth of a hertz, a frequency far below the threshold of hearing. What the listener thus hears is a minute of silence, as the course of the vibration remains imaginary. There is, however, a way to audibly follow the vibration: if one stops the playback during the piece, one can, depend-ing on one’s temporal position, hear clicks of different loudness, which are creat-ed by the loudspeaker membrane reverting to its initial position. Volker Straebel’s Chromatisch (8 Oktaven über 1/8 Hz) is based on a similar principle. It is a com-position that may serve as a paramount example of Segmond’s conceptual backdrop: ‘In my piece,’ Straebel writes, ‘a sine wave ascends eight octaves up-wards from a frequency of one-eighth of a hertz to a frequency of thirty-two hertz. Each frequency appears for the duration of one cycle, so that the pitch also determines the duration.’ For the longest time nothing is audible; yet again audience participation is required: stopping and starting playback again creates clicks. If one repeats that procedure regularly, one can to some extent trace the waveforms.

Despite the many diverse approaches exhibited by the sixteen participants, the project is based on a clear technical and aesthetic stipulation: all the compositions have been realised using Segmod, instead of with miscellaneous available sound-synthesis methods. The limitless space of possibilities bears the risk of slipping into total arbitrariness. In this sense, being limiting to a (comparatively simple) non-standard synthesis method such as Segmod seems consistent. The more limited and one-dimensional the options are, the farther the radius of creativity may reach.