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Plastic Music, Aural Models and Graphic Representation


In 2005, Parables, several studies for solo cello were presented using aural models in place of written scores. The impetus behind this was to remain within the rubric of “plastic sound” and include instrumental composition. These studies led to the composition of two works for fixed sounds and instruments also using aural models for the players. Several performers have played Analogies of Control and K. I have had examples and suggestions from some of the performers which I am using to adjust the procedures for the next investigation.

Most of the process remains the same as in the previous series, that is, a single-source acousmatic work will be made (this time from paper samples) as a way to establish a relationship to the source materials. Aural models will be made for solo performances from those same source materials (as in Parables). Then the recorded performances of the solo works will be used as source materials for the instrument and fixed sounds works. As in Analogies… and K, the mixed works will be made initially as acousmatic pieces from a pool of two sources; the solo instrument samples and the paper samples. The sounds will then be separated according to their source objects (viol or paper). The paper samples will be used for the instrumental models via headphones and the instrumental samples will be diffused to the audience.

Performers’ feedback included requests for visual representations of the both the models and their counterparts (cellist Thomas Gardner already made his own). Other requests include restricting the models frequency ranges in regard to their target instruments and using larger ensembles with which to render the performances.

This investigation therefore will include: 1) multi instrumentalist works (duos and trios); 2) the use of frequency information to inform the construction of the aural models; and 3) graphical representations of the performers’ extant aural models and the fixed sound counterparts.

Audio examples and performance demonstrations included here use both acousmatic and performed extracts from the trumpet and fixed sound piece, K, and the cello pieces, Analogies of Control and Parables.

Keywords — music analysis, musicology, aural models, plastic music, musique plastique, concrete sound, musique concrète, acousmatic, dynamic forms, ecological forms, metaphor, interface.

Introduction and Review

In works for instruments and fixed sounds, many composers have, historically, been writing in a multi-media situation. Musical manuscripts related to traditional notation, and graphical scores designed by individual composers for specific works, are created alongside digital and analogue creations using concrete methods; that is, manipulating sounds “by ear” with hands on real-time controls in a constant feedback loop of proprioceptive adaptation. Although the composers’ “inner ear” or aural imagination has proven quite sufficient to the purpose of integrating these two worlds, the fact is, that there are still two modes of conduct in use. By writing, one relies on a socially mediated code with a history of shared understanding between composers and performers. The other is a creation of the thing itself. It is the music, not a plan for creating music to be given to a specialist interpreter. A naïve listener can hear the model that the player uses and know what is being attempted.

Five studies were prepared as experiments towards creating other works for instruments and fixed sounds. In the studies, fixed sounds are used in place of musical manuscript. The performer, who is the only one to hear the model, is asked to imitate the sounds he hears as accurately as possible. This puts the cellist in an analogous position to the studio composer. He is using his instrument to synthesize new sounds in response to others. Also, composers of written music share an understanding of intent with instrumentalists in manuscript. This use of an aural model allows an instrumentalist and composer again to work on another common ground. Int this case they both are using a combination of aural acuity and technical expertise to re-synthesize auditory signals in a musical fashion.

These solo studies are also of interest in that they are a “special case” (Mooney 2005) of electroacoustic composition. Although the model-score is an electroacoustic construction, it is a solo instrumental performance. The audience hears only a solo cello.

The works for which these experiments were conceived are Analogies of Control (cello) and K (trumpet). They are “mixed works” for performers and fixed sounds.

Analogies of Control (2005), for cello and fixed sound

There have now been three cellists to perform Analogies of Control: Thomas Gardner, Craig Hultgren and Edgardo Espinosa. In some ways Analogies of Control is more typical to instrument and fixed sound works in which the performer reads a score written to integrate with an electroacoustic part. However this work, by approaching the instrumental part of the composition as an electroacoustic construction, allows both parts to be created in a single (aural) modality.

The parts that were to be later separated and used as an aural model for the cellist were made from the same source objects that the cello studies used, heat activated metals. The rest of the piece is built from cello sounds and their computer manipulated derivations. I used various approaches with the instrument as a sound source, including standard practice bowing all the way to a complete physical dismantling of the instrument and improvising with its separated parts. Tuning pegs were bounced on the body and fingerboard, strings were drawn through the f-holes. Bow and pegs were swirled across the back of the body. Improvisations on cello by Hultgren and some by myself and samplings of Hultgren's renditions of Parables were also included as sources.

During the course of creating the work, little regard was made as to where the sources came from. The extraction into model (score) and accompaniment (diffused) happened after the fact. In mixing the piece for performance, three tracks are made. Two are to diffused to the audience and the model is delivered to the cellist via headphones. Just as in the Parables, no one but the cellist hears the electroacoustic model. For the audience that means that what is heard either comes from the cellist, or it is sound derived from cello sources and manipulated in the studio. The audience doesn’t hear the original composition as it was made as I, the composer, heard it when I used the heat-activated metals in the model.

The audience hears a performance of acoustic cello and cello-derived plastic sound.

Bell Crawler: acousmatic
Bell Crawler: Hultgren
Bell Crawler: Gardner
Skimmin: acousmatic
Skimmin: Hultgren
Skimmin: Gardner
The Last Three Minutes: acousmatic
The Last Three Minutes: Hultgren
The Last Three Minutes: Gardner

Three Examples and Comparisons of the Performance and Acousmatic Versions

Performers’ Perspectives

Each cellists’ performance is meant to be the result of the player’s interaction with the sound world of the model and the possibilities in the sound world of the cello. The visual aspects of the performance were rejected out of need to see how this new technique would work in its most distant form from textual-social-visual mediation. However, despite my intent towards “aural purity” it has also turned out to include varying degrees of rhetorical interpretation on the part of two of the performers as well as visual aids being employed by one cellist.

Judith Mitchell, in regards to Parables, is taking the idea of mimicry literally. She believes that mimesis is at least approachable and possibly achievable. She uses no visual aides. Her interest is in the studies, not on the larger works.

Thomas Gardner has approached the model as a symbol of the sounds he is presumed to make. Remarking that since the sound itself is an impossible task, then he chooses to determine what the sound might represent, and he attempts to represent that on cello. That separation from template to symbol is also furthered by his use of visual scores similar to the diffusion scores used in the performance of acousmatic concert works.

The intent was that the player would synthesize and perform the closest possible imitation of the actual sound. The tension between intent and perceived success would be the player’s route towards self-expression. It is not dissimilar to Brian Ferneyhough’s music in which the score, being impossible to actually play, reveals the “variable distance” between the score and the performer (Sheridan 2005).

In Gardner’s approach, using this “sound symbol” mediation the player can attach a graphical symbol or an emotional content to the sounds of the model and allow that extra-aural framework to determine the representation of that “sound symbol”. The player mediates his experience and echos back the sound from all the senses after they’ve churned together in resonant sensory space charging through the haptic/kinesthetic senses through the muscles and into the strings again then air and bone, and back in the ears. That loop seems to take approximately half of a second according to the recordings from Hultgren’s performance in which he reacts in real-time to the signal, with no visual aids. Gardner’s visual aids are made the same way many acousmatic concert performers make diffusion scores. Since this is his visual representation of the aural model, I can accept its adherence to the aurally centred program.

There will be continued reinterpretations of this method as it moves between players. There is no “common practice” as yet.

Craig Hultgren, in talking about the technique in general has said:

Craig Hultgren
Craig Hultgren

Semantic orientation to sound has captured the imaginations of experimental composers and improvisers alike. I tend to be more instrumentally pragmatic and concern myself with the successive organizations of sounds, but that’s more or less the domain of a player. … As a player and interpreter of scores, I do look for rhetorical or semantic instructions to help characterise the manner and inflections of my playing. You’re correct in that the pragmatic part comes in the actual act of playing where I’m not really thinking “blue” or “green” or “spectral”. Cognitively, I’m oriented to the actual sound and its production from the instrument. (Nance 2007).

Hutlgren’s performances are real-time renderings of the models as they happen. There are no visual aids, rehearsals are real-time as well. Memorising the models has yet to happen in any significant way, although the renderings have been continuously evolving since he first took the work into his repertoire.

K (2007), for trumpet and fixed sound

K was built much like Analogies of Control. The same heat-stressed metals were used for the instrumental model, however the separation by sound source was not quite as strict. Some of the freezing metal samples are in the diffused tracks and there is a lot of cross-synthesis between trumpet sources and the metals. There has been one public performance of K, done by Drew Petrie in Glasgow. It was presented in the dark, as an acousmatic piece for performer.

K: acousmatic
K: Petrie

Comparison of the Performance and Acousmatic Versions

Technical and Performance Details

The works are available on a CD with 24-bit audio files for both the aural models and the diffused parts. Also included is a schematic (fig.1) showing the routing of the three channels.

Figure 1
Figure 1. Performance signal routing.

Also included are instructions as to which sound files are to be routed to the headphones and which to the audience. The signal routing for K is the same as Analogies of Control.

Variations and the Future Form

Hultgren has also asked that in the future that the choices in the model be somewhat pared down. He finds that having too many choices might not be working as well as a more restricted pallet. He suggests restricting the frequency range, for one thing, to an area more suitable for a cello.

It is true that the models in this piece were rather dense, and I left a lot of decisions to the performer. Future works will very likely be pared down in the ways that have been suggested. Towards that end the next works will involve violin, viola and double bass and trombone. Although there will be a concerted effort to restrict the models and simplify the choices that the performers will have to make, it should be remembered that part of the structural tension that is at the core of these works is the inability to completely mimic the model.

Multiple and infinite choices are central to the æsthetic, and every performer should be expected to interpret the same model in his own way. The “disjointed” nature of the form should allow the performer to find his own path through the models that are unlike any other’s. (Eco 1994) As in music of New Complexity, the interest is in the “variable distance” between what is there to reproduce and the performer’s actual reproduction of that sound. As a performer gets to know the piece over a period of years, his ability to hear the details of the model will improve. The results should vary considerably over a period of time and each performer’s interpretation of the model will be distinct.

The Senses as Perceptual System: Further Investigations

During the first experiments all information given to the performer were created in a way to restrict everything to auditory channels. The investigation will continue with this as a formal conceit, especially in the first stage of the new pieces.

New Studies, Same Plan

As in the first set of Parables, solo studies are created using the non-instrumental source samples. The samples in this case will be from scraped, torn, crumpled, bent folded and variously mutilated different grades of paper. Again, as in the first set of Parables, the performer will be instructed to mimic the aural models prepared from those samples and there will be recordings made of the performances by the target instrument.

Expanding Instructional Bandwidth

The advice and examples of the performers as well as my evaluations of the performances will be taken into consideration before the next series of pieces will be made. The procedure that will be used to build the pieces starts the same, but adds visual input in the form of graphical models derived from the aural models’ spectrograms. The piece’s fully aural nature is less obvious than it was before, but in an attempt to give the performer a chance to synchronize closer to the diffused, fixed part, graphic maps of the aural models will be included so that the performer can access the model asynchronously, that is, they can see what is coming and prepare for it prior to the time that unfolds, just as they would any other score. This will be a less alien soundscape for a trained performer that the other two works and hopefully will be easier to memorize.

The pieces will still be created in studio in their entirety prior to being rendered for live performance. The renderings this time will include graphics, common practice references like measure markers as well as sonograms for easy reference in combination with standard manuscript, although the pitch indications will not be restricted to standard scales. The staff notes will be good starting points to make it easier for a classical reader.

The part of the piece that is to be diffused will be made from samples of the target solo instrument. It is still up to the performer to bridge the sonic gap for the audience. The player is still the only one to hear the non-instrumental model and still all the sounds the audience hears will be from the instruments or derived in studio from that instrument. It is again up to the performer to be responsible for a sense of “spectral ensemble” in order to reintegrate the parts for the audience.

Some attempt to integrate the performances even further may include giving the players access to some of the same filters and effect processing that the in-studio processes.

Concluding Remarks

At first glance this move towards non-aural communication between composer and performer would seem to negate the point of of the initial exercise, and it was with some reluctance I went in this direction. As it happens, and as I began to work out some of the details, I have concluded that it is still well within the overall scope of the original intent.

The only thing being added is a rendering of an already existing aural model. Much of those graphics will be dictated by mostly mechanical transcriptions guided by aural cues. The players’ kinæsthetic-haptic senses have always been in play, and long-time classical players’ visual senses are tightly tuned to their aural acuity. I have accepted before the notion that the senses can not in reality be separated and are actually a perceptual system. This change is a natural step forward.

The studies maintain that aural purity and since there are no issues with synchrony, they need not have visual cues. Although in some way they might benefit, and I encourage and welcome the players to create their own graphic models of the works. This will just add more “neural real estate” to their auditory understanding of the pieces. Any moves to add more information to the picture must have its raison d’etre in the service of audition. Just as the eyes help re-tune the ears in a crowded room, or the fingers inform the eyes on a finely textured sculpture, other senses can be and are often about hearing. This investigation continues in that vein.


Eco, Umberto. Six Walks in the Fictional Woods. Cambridge, London: Harvard University Press, 1994.

Mooney, James. “Sound Diffusion Systems for the Live Performance of Electroacoustic Music.” Unpublished PhD dissertation. Department of Music, University of Sheffield, 2004. Available on the author’s website.

Nance, Rick. “Compositional Explorations of Plastic Sound.” Unpublished PhD dissertation. Leicester: DeMontfort University, 2007.

_____. “Performance and the Aural Score.” Proceedings of the Digital Music Research Network (DMRN) Summer Conference 2005 (University of Glasgow, 23–24 July 2005).

Sheridan, Molly. (2005) “The Melting Point: Two European Composers in America. In Conversation with Brian Ferneyhough.” New Music Box — People & Ideas in Profile. 1 September 2005. Available online at . Last accessed 8 October 2006.

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