Processed shimmer


Ruben Sverre Gjertsen

The Wheels within Wheels sound installation is a result of three years of improvisation sessions and recordings, initiated by Ruben Sverre Gjertsen, with the Wheels within Wheels research group and Ensemble Currentes. Electroacoustic elements and installations were mentioned already in the research proposal: the project should span the range of the performance of historic music and new experimental music, with possibilities of interest to composers today.

This sound installation is a large, open-ended bank of materials developed and selected for use in concerts or gallery spaces. Combinations and orders of sounds will be different every time, controlled by algorithms or directly by the composer. At the bottom of this page you will have the opportunity to experience this sound installation.

An artificial world could be composed of a number of elements or categories, and we could spend time describing each of them in in relation to the research project. As this is a brief series of examples from a larger exposition, I will refer to the full exposition for a more detailed discussion of each sound type present in the installation.1

The triangle of interaction can be decomposed, all three edges do not need to be present at all times.2 We can gradually remove the medieval repertoire.


  • We hear the performers within a medieval ensemble improvise, on reconstructed historic instruments, but the music is timbral abstractions and extended instrumental techniques, not medieval music.
  • The "Processed Ciconia" is a recorded medieval composition which has been digitally manipulated in numerous versions.3 Pitch-shiftings and spectral processing will abstract the music: you cannot always recognise the original structure of the music.
  • The "Mass text" contains text from the Latin mass, which was used in medieval works, but without the medieval music.
  • When the mass text is replaced by James Joyce, the direct link to medieval works is gone. Yet, we already used some of the same timbral means to abstract medieval compositions.4


These are steps in continuous metamorphosis and interaction between medieval works and compositional aesthetics of the past century.

Some of the first improvisations had very few guidelines. Helmut Lachenmanns "timbre types" was one of several approaches to narrow down the improvisations into building blocks for a sound installation. Rather than following specific rules of counterpoint, the musicians were searching for fragile and risky sounds, like "shimmer".


Helmut Lachenmann has offered descriptions of "timbre types in new music",5 which are closely related to temporal experience and structural function. These can describe building blocks of music not relating primarily to traditional harmony, melody, and counterpoint. A few categories are listed, which I will briefly sum up, simplified for the purpose of our improvisations.

    Kadenzklang is used in a wider sense than the tonal "cadence". It is a marked event of attack and decay, composed of any kind of sound, tone or noise. I would simply understand it as "something is happening", as opposed to pure being in time.
    Farbklang is a static field of colour with a vertical sense of time. The functions of this and the next two types are not related to their duration, as opposed to Kadenzklang. They can be long or short.

    Fluktuationsklang is a field of sound, fluctuating with inner activities that have no character of development or transformation.

    Texturklang is a densely woven polyphonic texture, where Ligetis micropolyphony is used as an example. We can add our dense versions of medieval polyphony.
    Strukturklang is at the structural level above the four first elementary types. It is a composition which can contain constellations of any of the four types.

The list is very short, and Lachenmann makes no claims of having a complete list for any musical situation. Yet, I6 found this a useful starting point to narrow down our7 improvisations. The Kadenzklang is put in sharp contrast to "being" in a time of colour, fluctuation, or texture. It does not emphasise metamorphosis, long-term transformations, and particular types of dramaturgy.


It is not just a matter of reproducing particular types of sounds. We do not choose to work with sound or temporal experience separately. These dimensions are interwoven. The Klangtypen are defined by their temporal function, as being in time (Farbe and Fluktuation), or signals of abrupt interruption (Kadenz). For me, a sense of verticality has been highly interesting, and a characteristic experience of music since the twentieth century. To build a large collection of sounds to be combined in any constellation, we must reflect on their temporal function. A static being in sound will be very different from a dramatic excerpt of a Wagner opera. I chose to search for dwelling moments and interruptions for this sound installation.


Jonathan D. Kramer has described moment form in the following way:

I have defined moments (...) as self-contained entities, capable of standing on their own yet in some nonlinear sense belonging to the context of the composition. The self-containment of moments is provided either by stasis or by process. Stockhausen has written: "Each moment, whether a [static] state or a process, is individual and self-regulated, and able to sustain an independent existence."8


A shimmer sound could function as such a self-contained moment.



To find materials for a sound installation, we recorded a large number of improvised versions of each sound type. Each musician found a new pitch and a new type of sound for each cue. I found the results of these individual choices rich, with unpredictable distributions of high and low tones. There was no need to make overall plans and sketches of harmony. In collective disembodied sounds, it can be difficult to distinguish the effort of each individual.



When Lachenmann describes the Fluktuationsklang, he turns to Chopins Étude op. 10 no. 1, fluctuations of natural harmonics in Ligetis "Atmosphères",9 and Ravels  "Lever du jour" from Daphnis et Chloé.10

These situations have vivid actions up and down, yet are static by nature as the overall shapes do not develop. The Chopin and Ravel examples are guided by harmonic progressions establishing expectations and cycles.

Our "fluctuation" recordings are closer to the stasis of Ligetis fluctuations, which do not have progressions of harmony. They overlap with the "shimmer" type, whisperings of Joyce, and concrete use of water sounds. Currentes came up with a good variety of extended sound fluctuations, leading to abstraction of the medieval instrumental group.


This is part of the feedback loop of our research project; the musicians were taking part in the creative process and the composers made selections and edited the results.


Dry and wet spaces11

We were interested in influences particular spaces could have on a recording session. The resonant dome in Tårnsalen at the Kode 4 museum in Bergen, and the completely dry anechoic chamber at Haukeland University Hospital, gave a maximum contrast of spatial experience.

Tårnsalen has a prominent flutter echo directly underneath the dome. For the recordings, I placed the soundfield microphone12 in this middle area, while the musicians performed at the sides of the room.

Our "Joyce whisperings" were based on extracts from Finnegans Wake.13 I suggested ways to deal with the text; concrete whisperings of text, whisperings obstructed by the hands, inhaled or exhaled in unpredictable patterns, whispering through an instrument, imitating speech with an instrument, stretching and changing the chronology of the text, and free sound explorations. It should all be at a balanced whispering or barely voiced level. The approach is similar to our "Soto limperio" improvisations. We suggest ways of relating to a literary or a musical text, and the detailed composing is done by the musicians.

The anechoic chamber added a near claustrophobic experience. The room gives nothing, recordings are very revealing and can capture a wide range of details easily blurred in a resonant space.

Recording session in the anechoic chamber at Haukeland University Hospital. (Left to right: Jostein Gundersen, Ruben Sverre Gjertsen, Ingvill Holter, Hans Knut Sveen.) It is not possible to project this dryness into larger spaces. The performance acoustics will always impose a minimum resonance.

In Tårnsalen, the musicians walked around, exploring the acoustics of different positions, inside and outside the room. The subtle Joyce whispering could balance louder sounds coming from outside in the hallway. Those outside could create a certain energy of being trapped in or expelled to the hallway. There were outbursts of polyphonic singing and shouting I found highly interesting as a composition, standing against the whispering stasis elements.

Wheels within Wheels recording session in Tårnsalen, Kode 4, Bergen. Hans Knut Sveen, Ruben Sverre Gjertsen, Ingeborg Dalheim


Lachenmanns understanding of Kadenzklang is wide. We narrowed this category down to very short events; attack sounds or reverse attack sounds. We encouraged: "Be inventive, try to continuously discover new types of sound." I did some times edit and superimpose sounds to make the attack events denser.

In counterpoint and harmony, we have principles to avoid parallel fifths and octaves (the rules were much softer in the Ars Nova era), and be aware of the possibility of counter-movements. When creating multidimensional sound events it could be equally useful to avoid moving in parallel on all parameters. A possible contradiction would be ascending pitch and decreasing loudness.

A kaleidoscope of sounds

Helmut Lachenmanns Strukturklang14 is a composition of all subcategories like Kadenzklang, Farbklang, Fluktuationsklang and Texturklang. The Wheels within Wheels sound installation is a bank of materials continuously appearing in new combinations. There were three different sound installations, for three different locations and situations. A large collection of sounds was sorted in folders, while setups for type of sound and probabilities were different for each of the locations. A random sound within a sound category was triggered at a random time within a given time frame. In principle, any sound should be able to be combined with any other sound. That requires thought about the independence of each sound, its "moment" character. Sounds should not require a particular context, rather act like inclusive environments.

The Wheels within Wheels sound installation is based on the described improvisation, used directly and with digital timbral and spatial processing.

Potential combinations and patterns are endless and able to surprise me. Installations like these could play for years without repeating the same composition. Im not concerned with exactly how many years. After some time, you will have experienced the main fragment types.

Now you can go ahead and create your own composition from these building blocks of similar or contrasting families of sound. You will find again the previously demonstrated sounds, and a few types which will not be discussed in detail here. These are not all the sounds, but a good selection of them.

Wheels within wheels

Interactive sound installation

Processed fluctuation

Processed Ciconia



Granular attack

Glass and water

Joyce water

Tårnsalen Joyce

Anechoic Joyce

Mass text

Processed mass text