Even in Berlin, a town that sees concerts of new music practically every day, this mini-festival had something special about it. The three concerts performed by Berlin’s ensemble mosaik attracted a diverse audience, not only the usual “friends and family” of the composers and performers, but also a broader audience ranging from youngsters in knitted caps to people from the art-opening scene. The venue was the vat house of what was once a functioning brewery, now transformed into a cultural center while retaining the essence of its original atmosphere.

Ensemble Mosaik is an initiative formed by graduates from Berlin’s Hochschule der Künste. Since its founding in 1997, the ensemble has, under the direction of composer Enno Poppe, built a reputation both for high quality musical performances of the newest in new music—performances often prepared in close association with the (mostly younger) composers—as well as a knack for originality in the programming of their concert series. The audible interfaces event was the first time the ensemble invited composers from around the world to submit works using live electronics. The festival title provided a programmatic description of what the musicians wished to present to their audience: the means by which live electronics crosses (or treads on) the frontiers between what ensemble mosaik calls “the three fields of interpretation, improvisation, and installation.” The ensemble was ably assisted in this enterprise by “tonmeisters” associated with the Electronic Studio at Technische Universität Berlin. The mixing console was as much a site of artistic virtuosity as anywhere else on these evenings.

The first concert presented premiere performances of Harald Muenz’s The Self Composer (1999–2002) and Keiko Yamanaka’s Resound (2001), as well as two older pieces: Marco Stroppa’s Spirali (1987/88) and Claudy Malherbe’s nonsun (1984). On the following evening, Arnulf Herrmann’s Sextett (2000/01), Enno Poppe’s Holz (1999/2000), and Jörg Mainka’s Skalenwirbel (1992/93) were performed. The final event commenced with a sound installation by Orm Finnendahl, which had also been presented as a concert dénouement on the first two evenings. In the closing concert we heard performances of Calving Ground by Ed Osborn (2002, world premiere), TEXTURE-MULTIPLE by Agostino Di Scipio (1993–2000, German premiere), as well as Mr. Finnendahl’s Kommen & Gehen (2000), and a revised version of El jardin de senderos que se bifurcan (2001/2002) by Ana Maria Rodriguez.

Rather than reviewing all 12 works here, it seems more interesting to look at the means taken and goals followed in seven selected pieces, with a particular focus on the use of electroacoustic media.

The first piece in the festival, The Self Composer for sight-reading oboist and laptop computer by Harald Muenz (born 1965), marked one extreme in the use of computer technology. This concept piece is based around a collection of 23 orchestral excerpts from the oboe repertoire, prepared and stored in computer memory. Of these, two are selected at random immediately prior to a performance, with the computer generating a new part by combining elements from the two and the oboist sight-reading the result as it is displayed on the computer monitor. In this way, an open competition between performer and computer is created: human and machine play in unison. In the course of the three sections of the work, increasingly strong contrasts are staged: the noble timbre of the brilliant soloist (Simon Strasser) versus the rather cheesy synthetic computer sound; a more human (and approximate) intonation versus the mechanically perfect. However, the composition leaves one question open: is it (and to what extent) generally possible to succeed in opposing or breaking with the overpowering historical aura of tonal materials?

Arnulf Hermann (b. 1968) presented, with his Sextett for three strings, two winds, piano, and electronics, an essay on the difficulties of recollection and on the unnoticed restructuring of memories that takes place in the process. The third movement—entitled 8 Takte im Gegenlicht [“Eight backlit bars”]—is based on a passage of particular rhythmic and harmonic interest, taken from the Cavatina movement of Ludwig van Beethoven’s String Quartet, Op. 130. Both the original version and deviated forms of the extract are interwoven in numerous structural layers, with glimpses of the familiar appearing beneath strata of the unfamiliar, a sort of interrupted or broken speech. For instance, the original harmonic structure is present as a kind of scaffolding encompassing the entire movement; at the same time it appears in foreshortened form, linearly shifting (not transposing!) frequencies. On top of this, the original melody is carried by the viola accompanied by a pointillistic, accented version of the same tune. A series of prepared soundfiles, triggered by the pianist during the performance, pick up and spatialize noise-like sonic materials in a five-channel configuration.

The second movement, “Artificial Flavor,” has, as a middle section, a cleverly devised rhythmic and spatial canon, in the course of which instrumental timbres imperceptibly give way to concrete sounds. This is followed by a transition to the third movement, a solo intermezzo of electronic tones with slowly sinking pitches. For this section, Mr. Herrmann had recorded crotales, subjecting the samples to extreme time-stretching and filtering, letting the sounds wander around the room at varying speeds. “Disruptive activities” were composed into the music, preventing the music from becoming too obvious or smooth. Instead, attention was kept high by the remaining uncertainties in attempting to recognize the familiar.

In his composition Holz [“Wood”] for clarinet and ensemble, second in a recent series of three pieces for ensemble (the others are titled Knochen and Öl—“Bones” and “Oil”), Mr. Poppe (b. 1969) makes thorough use of a harmonic technique he has experimented with in earlier works. The harmonic organization of a musical idea (for instance, a polyphonic melodic passage) is generated by calculating the frequencies that would be generated by a ring modulation of two or three pitches in the underlying polyphonic structure. These would then be “simulated” by harmonic structures consisting of anywhere from four to nine pitches. These structures, played by MIDI instruments, naturally contain further partials and difference tones. As a further step, these harmonic structures would be taken up by the instrumental ensemble. In consideration of the limits of human intonation capabilities, microtones are quantized to the nearest eighth of a tone. During the performance, a keyboard preset to an appropriate scale served as a reference point for the instrumental intonation. The threat of this systematic harmonization capsizing into downright out-of-tune performance in the more complex passages is a risk Mr. Poppe takes with a smile. In his words, “staging a conflict in which a compositional system comes under question through its own rules” is a matter of personal interest. The microtonally enhanced harmonic structures (or “polyspectral chords,” to use Mr. Poppe’s phrase) resulting from this process elicit a tonality with a characteristic all its own. This, together with the distinctive musical character of the work, constitutes the fascination of this instrumental composition.

In Codex II, by Richard Barrett (b. 1959), for oboe, saxophone, piano, and live electronics, the composer was present on stage with the other performers, playing LiSa, a “software instrument” developed at STEIM (Studio for Electro-Instrumental Music) in Amsterdam. This software allows direct manipulation and playback of both previously sampled sounds as well as sounds recorded during the performance. Mr. Barrett values the flexibility of the interface as well as its palpably tactile aspects—reminiscent of acoustic instruments—in an instrument that still offers the variety of timbres available in the electroacoustic medium. The form of the piece, a series of strongly contrasting states, was developed during rehearsal. The score is, accordingly, more a system of what Mr. Barrett terms “frames” for the ensemble music rather than a finalized performance instruction.

Ana Maria Rodriquez’s El jardin de senderos que se bifurcan refers to a tale with the same title written by Jorge Luis Borges. She picks up Borges‘s image of a temporal labyrinth, branching subterraneously from each of its points, reminiscent of hypertext. In the original version of the piece, performed at the Donaueschingen Festival in 2001, Ms. Rodriquez projected this image of a temporal labyrinth onto a spatial one, making use of a two-story gallery under the roof of the royal library in Donaueschingen. In that situation, the audience could wander through the space during performance. In the Berlin version, with only a single room, the piece was presented in a condensed form while retaining the basic concept. Each of the three instruments (bass flute, oboe, and cello) was assigned, prior to the performance, 15 short, mostly noise-laden, passages. The piece is created by the computer during the performance by choosing random combinations of these phrases and displaying the calculated parts on monitors for the musicians to play. The two woodwind parts, resynchronized to a common meter again and again, play against long cello pedal points that remain in an independent meter. The instrumental sounds are fed back into a Max/MSP-based system and transformed. The Max patches themselves generate their own meters, creating a third temporal layer. Ironically, it was the temporal linearity—the very aspect that Ms. Rodriquez was trying to break with—that became predominant in the listener’s perception of this performance. The presentation in Berlin whets the interest for experiencing the spatial version of this composition.

TEXTURE-MULTIPLE for two winds, two strings, percussion, piano, and live electronics, by Agostino Di Scipio (b. 1962), is a piece which has been extended in every new performance since its premiere in 1993. Each of the instrumental parts is independent, taken from a very limited stock of practically identical elements but developed autonomously. Nonetheless, the voices can become transparent parts of a whole. During performance, the individual parts repeatedly come together as a collective ensemble, only to be destroyed. The computer intervenes in the instrumental action through a special technique of multiple granularization with different time-scale factors. This granularization is dependent on the resonant properties of the performance space, which is tracked by a microphone placed in the middle of the room. Mr. Di Scipio calls the resulting feedback loop an “ecological system . . . in the triangle between musician, machine, and space.” In his words, the composition is not so much a piece of interactive music as an attempt to “compose interaction through which music is created.” The result is a highly exciting affair, not only for the audience but also for the performers.

Both the composition Kommen & Gehen, for solo violin and live electronics by Orm Finnendahl (b. 1963), and his sound installation of the same name were originally conceived for the German Pavilion at Expo 2000 in Hanover. Starting with three prerecorded violin samples and sounds recorded directly from the violin during performance, a special recursive process of granular resynthesis takes place. Time scaling and overlapping of materials (at times on the order of a thousandfold) is used to generate the extremely thick sonic material of the piece. The interaction between soloist, with its hesitant, deliberately unstable tone, and the electronic manipulation of this material to overpoweringly engulfing waves of sound, is made evident for the listener through effects such as the apparent “switching off” of the computer-generated sound through Bartók pizzicati coming from the violin. Mr. Finnendahl’s ability to simulate an almost tangible spatialization with eight loudspeakers was impressive.

For the composers presented here, all born in the period from 1959 to 1969, it has long since become the natural course to use of computers at all levels of their compositional efforts, even in purely instrumental works. The musical results are accordingly widely diverse. The composers make use of available software, or develop their own extensions, without relying on dogma; working independently, for the most part, of larger studios.

The computer is used for a wide variety of tasks: as an aid in simulating the solution of harmonic questions (Mr. Poppe, Mr. Herrmann); for the creation of aleatoric works in which random number generators select and combine elements taken from predefined materials, transporting the resulting score to the performers directly on monitors (Ms. Rodriquez, Mr. Di Scipio, Mr. Muenz). It can be used in executing algorithmic compositions (Mr. Finnendahl, Mr. Herrmann, Mr. Di Scipio) or in pieces that work explicitly with spatial elements (Ms. Rodriquez, Mr. Herrmann, Mr. Finnendahl, Mr. Di Scipio). In concept works, which often critically scrutinize the relationship between human and (supposedly perfect) machines, the computer appears with an apparently subjective character as partner to the performer (Mr. Muenz) or meets the musician more as a traditionally “playable” instrument (Mr. Barrett). The composers play, more or less openly, with the effect of direct confrontation between musician and a rack of technical equipment, or the musicians’ reactions to sounds echoing back at them from the concert hall. The associations generated in the audience by these effects are reminiscent of many communicational processes—both successful and failed—taking place between humanity and technology.