On May 1st, 1967 I had just arrived in Cologne from Berkeley, California, to take up my new position as Stockhausen's personal assistant. We had met in his composition seminar at the UC Davis campus. It was a heady, doubly significant time for me: I had decided to swap a graduate degree in music for an apprenticeship with the Master and I was returning to Germany, from where my family had emigrated in 1953. Already we were on the train to Basel, to rehearse his piece SOLO with Heinz Holliger, the Swiss oboist and composer. As we sped upstream along the banks of the Rhine, my mind racing through a maze of earliest memories, he disclosed in outline form his still fresh ideas for a new piece.

It was to be called PROZESSION. The ideas were, as usual, succinct and comprehensive: four instrumentalists would play a sequence of events, gradually transforming them parametrically according to a sequence of signs indicating an increase, a decrease or no change in one or a combination of the parameters duration, loudness, register and number of discernible elements within the event. The players were to refer to several of his own compositions as the source of all initial events. A few other instructions such as that each player should play at least one duration longer than one minute, and that some events must be clearly periodic in structure - both of which I supported enthusiastically - rounded out the picture.

PROZESSION was intended for the imminent May tour of 9 concerts by the Stockhausen Ensemble to Scandinavia and London, on which we would also be performing his MIKROPHONIE I, TELEMUSIK, KLAVIERSTÜCKE IX, X and XI and several electronic and electro-acoustic pieces by the young Cologne composers Michael von Biel (FASSUNG for 4-channel tape) and Johannes Fritsch (FABULA RASA for 4-channel tape and PARTITA for amplified viola, played by Fritsch employing a fantastic range of sounds and extended playing techniques, tape delay and filters, 5 players in all).

Stockhausen had intended to have his piece SOLO for instrument and multi-channel tape delay performed by Harald Bojé on this tour, but the equipment for the tape delay was proving difficult to perfect and the small electronic keyboard instrument Bojé had chosen to perform with - the 'Elektronium' built by Hohner - was judged unsatisfactory for this piece. There were no alternatives readily available. Faced with the dilemma of a missing piece for the concerts and recordings of an extensive tour, Stockhausen responded with his customary resourcefulness and ingenuity.

The 'Stockhausen Ensemble' of the time consisted of the six persons required to perform MIKROPHONIE I: four musicians in two teams playing and 'microphoning' the tam tam (Aloys Kontarsky and Johannes Fritsch, Harald Bojé and Alfred Ahlings) and two musicians for the filtering and sound projection of the two tam tam teams (Stockhausen and I). Kontarsky had performed all the KLAVIERSTÜCKE, KONTAKTE and REFRAIN numerous times, Bojé also played the KLAVIERSTÜCKE regularly, both Ahlings and Fritsch had performed MIKROPHONIE I numerous times and been members of the Stockhausen 'circle' in Cologne for some time already. Only I was a newcomer, discovered as a kindred spirit. We were a highly varied bunch, but strongly united by our intimate knowledge and deep appreciation of Stockhausen's music.

The WDR (the local broadcasting corporation, and also the home of the electronic music studio of which Stockhausen was the director and in which he had realised the STUDIE I & II, GESANG DER JÜNGLINGE and KONTAKTE) wanted to record the program of our tour; we therefore rehearsed in its studios and recorded there our first performances of PROZESSION for amplified and filtered tam tam and viola, electronium and piano on the 9th and 10th of May, 1967.

In the following I would like briefly to explore the evolution and extraordinary importance of this seemingly simple composition.

The score of PROZESSION (1967), consists almost entirely of various combinations of +, - and = signs, stacked in orderly rows, and certainly does not look like music; its title means 'procession', in the sense of a ceremonial parade or enfilade. As a musical score employing - at least in part - a symbolic, non-musical notation, it does, however, have antecedents, both among Stockhausen's works (PLUS-MINUS, SOLO, MIKROPHONIE I & II, and to some extent, MOMENTE) and among the works of other composers (John Cage, Earle Brown, Morton Feldman, LaMonte Young, just to name a few). It is distinguished from these, however, by the fact that the notation of PROZESSION alone encapsulates a process of parametric transformation which is to be invented in real time according to a symbolic notation. No prior translation of the symbols into sound-events and no preparation is required other than a thorough acquaintance with some of the previously composed music of its author, which serves as a resource for the sound-events that are to be subjected to this process.

In his own remarks on PLUS-MINUS (1963) Stockhausen said that he had intended the score to be a highly concentrated, symbolically expressed compendium of the structural foundations and originating formal principles of his own works up to that point. It would be expressed in such a way as to make it possible for others, composers and performers alike, to employ them in order to realise a multiplicity of versions.

Indeed, the score of PLUS-MINUS consists of a set of formal instructions in a symbolic notation of a varying degree of ambiguity and set of pages that serve as a reservoir of 'sound material' to be employed in the realisation of a version. The underlying process is one of growth and decay. It makes room for occasional interruptions by 'foreign' material, accompaniment by 'negative' material and the intrusion of unforeseeable or 'contemporary' sideline events of lesser importance. Stockhausen used the first sketches for PLUS-MINUS as the project work in a composition course he taught in Cologne in 1963. Afterwards, on the basis of the experience gathered from the efforts of 15 students at formulating a version he made revisions and alterations that were included in the final published 'score'.

In the same remarks, he goes on to say..."In the course of composing PLUS-MINUS, I consistently endeavoured to create the conditions suitable to living organisms, an environment favourable to 'musical beings' subject to an irreversible process of absorption and rejection of new material, experiencing mutation or even death."

In encountering versions of this work - particularly the one prepared by Frederic Rzewski and Cornelius Cardew - Stockhausen often felt that they had a stronger own life than any of his other compositions because they were not just performed but also realised by others, often employing sounds and sound sources that he himself had heretofore avoided. They were especially exciting, rewarding him with both the strange and the familiar.

SOLO (1966) for a melody-instrument with multiple live reiteration and delay, requires 4 assistants when performed with a tape system. It represents the attempt to create a piece in which a player seemingly thinks aloud and in which the audience does not simply hear a piece but instead witnesses an ephemeral, complex process of creation, reflection and decay. The player is provided with several pages of notated absolute and relatively pitched material, a choice of several different form plans and a set of qualitative and relational instructions on how and where the notated material is to be utilised within the form plan. These latter instructions call for the construction of polyphonic, block-like or chordal structures which are to be made up of elements, parts or whole phrases which are selected from the provided notated material according to criteria of similarity, difference or contrariness. The player's focus on his material and his relationship to it while he is playing (and hearing the multiple reiteration) is also to be composed, alternating between the present, the past and the future, between fragments remembered or anticipated.

It was Stockhausen's daring intention that this piece be realised live during a performance, without any written preparation of a 'version' other than perhaps practising the notated material and rehearsing with the reiteration and delay apparatus. Due to the innovative complexity of both the score and the electro-acoustic equipment, this proved impossible very early on.

MIKROPHONIE I (1965) for large tam tam, microphones, filters and 'sound projection', performed by two teams of three players, is the next work in the genealogy of PROZESSION. In this specifically electro-acoustic piece (in the sense of being both electronic and instrumental), one player in each of the two teams creates sounds upon the surface of the tam tam (using a very wide variety of wooden, metal, glass, cardboard and plastic materials and implements), another player manipulates the microphone and the third player alters the bandwidth and frequency of a variable band pass filter and the stereo output levels of his team's microphone channel.

The score provides 33 independent, graphically very precisely notated musical structures (of varying durations) that are to be ordered, combined and/or overlapped according to a 'form scheme'. Each of the the structures provides three interlocking parts:- for the tam tam player, usually alternating between two or three characteristically different sounds in as many different registers, in normal or time=space notation;
- for the 'microphonist', indicating the distance and position of the microphone relative to the tam tam and various characteristic movements, all of which influence the timbre and envelope of the sound;
- for the sound projectionist, prescribing the bandwidth and frequency to be set on the band pass filter as well as the relative loudness of the output.

The nature of the sounds to be produced are specified descriptively, for example, sawing, quacking, growling, crackling, clucking, trumpeting, rattling, etc. and not by the means which are to be employed in order to create them on the surface of the tam tam.

The form scheme prescribes a set of characteristic relationships that are to pertain between any two successive structures. In relationship to the previous structure, the succeeding one is to be either similar, different or contrary in nature; this relationship is to remain constant, to increase or to decrease; furthermore, as the two teams alternate in playing the structures (upon opposite sides of the same tam tam!) and the structures overlap considerably, any given structure is to be supportive, neutral or destructive in its effect upon the previous structure.

Thus, the players prepare a version of MIKROPHONIE I, according to a prescribed set of characterising, dynamic and functional relationships, fitting together a sequence out of an inventory of quite precisely notated structures. The fact that these structures were themselves composed in conformity with those characteristics and that these are entirely relational and functional principles is significant, as it reconfirms Stockhausen's continuing personal search - begun with KONTRA-PUNKTE - for new freedoms, new ways of thinking and listening, where participation in kinetic relational process takes precedence over recognition of rigid determinate structure.

In the course of explaining the definitions and 'rules of the game' to us at the beginning of the first rehearsal, Stockhausen made it very clear that in his mind, PROZESSION was not to be taken as an improvisation. Although we were free to make personal selections for the 'events' that we would transform, the points of departure were always to be events taken from some of his pieces. For the pianist Aloys Kontarsky, they were the KLAVIERSTÜCKE and KONTAKTE, for the Elektronium player Harald Bojé, SOLO and TELEMUSIK, for the amplified and filtered viola player Johannes Fritsch, GESANG DER JÜNGLINGE, KONTAKTE and MOMENTE, and for the tam tam players Alfred Ahlings and myself as microphonist, MIKROPHONIE I. In this sense, PROZESSION is much like PLUS-MINUS and SOLO: the composer provides a formal plan which is realised and fleshed out using raw materials which he also also supplied. However, the vital differences are that in these two pieces, the material provided, though ordered and highly differentiated, is basically structureless, and a version must be conceived and prepared by the performer(s) before it can be played. In PROZESSION, however, the material is extracted from a finished, aesthetically more or less consistent product. In part it is already gently transformed by the process of extraction from memory and adaptation to the instrument, moment and place. Finally, it is more rigorously transformed in real time according to the symbols of the score.

As mentioned earlier, the rules of play and transformation are quite simple: The players perform a sequence of events. Each event is to be a variant of an event in one of his earlier compositions. An event is defined parametrically by its overall duration, its relative register, its loudness and the number of discernible elements (subdivisions). The players begin when they wish. Once a player has completed his first event, he imitates either his own event or the event of another player, transforming its parameters according to a sequence of symbols +, -, and = in his part: + means longer, higher, louder and/or more elements; - means shorter, lower, softer and/or less elements; = means all parameters remains the same.

The players need not always take events extracted from Stockhausen's pieces as points of departure; they are free - at any time - to adopt an event being played by one of the others and use it as a starting point for transformation. It is this freedom of choice that marks both the beginning of a new tradition of improvisation and the closing of an old circle. It shifts the aesthetic ground and provides for coherence of the group.

In the first rehearsals, and indeed, performances, we tended to be quite self-referential and inward looking, each starting with our own event and transforming it for a while, and then changing to another event and transforming that for a while, and so on, only occasionally adopting an event from another player. We were thinking structurally (after all, three of us were composers) parametrically, step by step, and often tried envisage the final shape of an event after a long journey of transformations and encounters with other events, before setting out on that course. In discussions afterwards, Stockhausen always encouraged us to pick up events from others, to pass them back and forth, so that long periods would arise in which we were all - or two or three of us - transforming what was basically the same event, only in different directions.

We always set our instruments up in such a way that we could all see one another, including Stockhausen, who would sit more or less in the centre of the acoustic space, operating the filters and volume controls. Eye contact was essential, at least for me (on the other hand, the tam tam was large enough that we could, and would, often hide behind it). Quite early on I decided to augment my role as 'microphonist': I began also to make sounds, adding a second 'voice' to the events played by my partner. At the very first time I did this, Stockhausen was quite startled, staring at me with his eyes wide open when I finally peeked around the side of the tam tam; but he was also nodding. Afterwards he told me that my contribution in that performance had been exceptional and that he was excited by the way what I had played (a very long and insistently periodic sound) caused the ensemble to focus on my 'event' and to coalesce. Indeed, when it happened, I felt for a long period as if I held all the other players in my hand and could lead them wherever I wished. From that moment on, I never looked back and took every performance of PROZESSION as an opportunity to compose in real time, of course always in the best possible taste and according to the rules!

At the very beginning, while we were still discovering the 'personality' of the piece, in particular those consistently recurring broad phrases of alternating consolidation and dispersion of focus, Stockhausen and I often discussed the performances. His views were not only illuminating but also important because he was, of course, intimately involved in the articulation of the phrases. Through his control over the loudness and presence of the tam tam and viola microphones, he shaped the envelope of their sound and, through this, was able to influence strongly the overall dynamic life of the ensemble sound. Often he would play with the envelope of an event created by one of the two amplified instruments, superimposing another envelope on top of the shape the player was already giving it. The player would in turn react to this, sometimes reinforcing Stockhausen's shaping, staying with the event, in order to give him enough of the present 'material' so that he could develop his idea. As a result of this further plane of interaction, envelope shape, spatiality and its transformation became additional layers in the musical process. Stockhausen's heightened ability to 'read' what was happening and to lend 'acoustic' support to whatever it was we were trying to do, provided a formidable impetus for invention and concentration, especially for those two instruments. The other two instruments - piano and Elektronium - were completely independent of his dynamic control; this was a good balance.

Important also were the personalities of the players; here too there was a good balance.

Aloys Kontarsky - ebullient, confident, authoritative, forceful, humorous - possessed the almost unbelievable skill to sum up even the most complex timbre in a 4-7 note chord. He always seemed in control of his own situation, constructing and deconstructing along intelligible lines with clear independent goals, and yet almost always willing to participate in a 'joint venture'. His playing was as elegant as his speech and often as jocular as one of his favourite expressions, "Gesund muss es sein und flott muss es gehen!" (It's got to be wholesome and take off.)

Harald Bojé, on the other hand, - reserved, quiet, quick-witted, flexible, chimerical, sinuous, quietly enthusiastic - was a steadfast individualist who did not easily submit to synchronous ensemble antics. Although he often precipitated intense implosions, he usually bailed out just before things got too hot, ending up grumbling somewhere in the depths or screeching balefully in the stratosphere. He represented the entropic force that every ensemble needs.

Alfred Ahlings - solid, persistent, reliable, unsophisticated, patient, supportive - generally set the moderate, but often majestic pace which made room for everyone else. Establishing simple and predictable broad guidelines were his strengths.

Johannes Fritsch, truly a virtuoso on the amplified viola - humorous, versatile, adaptable, resourceful, even-tempered, seemingly indifferent - had a vast range of timbres which allowed him to blend easily with the more 'abstract' sounds of the tam tam and the Elektronium. On the other hand, he would often employ straight, classical string playing in order to absorb the piano sounds and take them to meet their more distant cousins.

And then, of course, there was myself - stubborn, insistent, experimental, renegade, purposeful, ambitious, - tending to search out unoccupied temporal and timbral domains, to pull others in my direction, to structure time independent of duration, representing the anti-entropic force that every ensemble also needs.

As a group, we did not discuss our performances very much, as is evidenced by my notes on a recording session held in Darmstadt on August 3, 1967: "We started at noon, played for an hour, looked at each other and shook our heads in silent disapproval. Had lunch, a short break for a nap and then another hour recording, and again, silently looking at each other, shook our heads. Took a break, went outside, lay in the grass, stared at the clouds. Went back into the studio and made another hour-long recording. When the last sound had died away we again looked at each other silently, this time nodding. After listening to the recording the first words spoken were by Kontarsky: 'Sitzt!', the German equivalent of 'It's a wrap.' We were finished at 9pm."

Over a period of three years we gave approximately 28 performances of PROZESSION and made numerous studio recordings, two of which were issued on vinyl. It is surprising how often I encounter someone much younger who says, "Oh yeah, I've got one of those,...bought it second hand. It's one of my favourites."