In the process of developing the work Field Notes, I made a Max patch to analyse field recordings and derive pitches, translate them into MIDI notes and record them as the basis of a score. It became easier to record the MIDI output into a Logic file where they could be further threshed into information that might become a score: the Max Patch was quite capable of generating data that was too complex to transcribe into a traditional score. (In fact it brought into focus just how little information can be captured in a traditional score: because of the temporal grid that the score imposes). In any case I found that the output could also be used to generate an interesting accompaniment for an improvisation. The sample below demonstrates this idea - using an electric piano sound that (to me anyway) sounded a little like the Zawinal/Corea accompaniments found in Mile Davis' Bitches Brew. I'm yet to turn this into a viable performance tool: it took a lot of tweeking to get the output heard here.
In the sense proposed by Deleuze and Guatarri, some of the earliest examples of rhizomatic works in Western Art music, include, Karlheinz Stockhausen Klavierstück XI , John Cage Concert for Piano , Pierre Boulez Third Piano Sonata [1963-], Mauricio Kagel Prima Vista [1962-3] and Earle Brown Event Synergy II . (It is perhaps notable that it was not necessary to negotiate functional harmony in a rhizomatic context in any of these works). These are works allowing for a multiplicity of re-orderings of different but determinate pathways to be explored, not simply exhibiting the non-linear “asignifying ruptures” found in Stravinsky’s Symphonies of Wind Instruments   or Charles Ives Holidays Symphony  [D. Thurmaier. Time and Compositional Process in Charles Ives’s Holidays Symphony. PhD Indiana University, 2006, 26-82. ], or “lines of flight” [J. Gilbert. Deleuze and Music. Edinburgh U.P., 2004] as found in jazz improvisation [J. Barham. Rhizomes and plateaus: Rethinking jazz historiography and the jazz-‘classical’ relationship. Jazz Res. J., 3, 2, 2010, 171-202. ].
Boulez, for example, describes the Third Piano Sonata as a Labyrinth, in which,
The itinerary is left to the interpreter’s initiative, he must direct himself through a tight network of routes. This form, which is both fixed and mobile, is situated, because of this ambiguity, in the centre of the work for which it serves as a pivot, as a centre of gravity [P. Boulez. Sonate, que me veux-tu?. Perspectives of New Music, 1, 2, 1963, 32–44: 41].
A number of problems beset the first generation of paper-based rhizomatic scores:
Although each of the works Ubahn c. 1985: the Rosenberg Variations , The Last Years , Sacrificial Zones , detritus  and trash vortex  utilizes a rhizomatic score comprising a network of connections, the formal structures that emerge in a performance derive from the manner in which the performers traverse the score.
Berlin the graffiti score begins to peel away revealing a five part harmonization of the East German national anthem in traditional notation, which they perform to end the work. Ubahn then, is a concatenative structure [A. Coenen. Stockhausen's Paradigm: A Survey of His Theories. Perspectives of New Music, 32, 2, 1994, 200-225.] comprising a freely rhizomatic first section, an indeterminate graphic notation section and a final traditionally notated section. The rhizomatic section has an idiosyncratic form in the sense that the pathway materials are quiet and combine together as a background layer, while the nodal points contain soloistic material. This arrangement highlights the nodal points and provides a contrasting, indeterminate texture.
detritus explores the “territorializing” [G. Deleuze, & F. Guattari. A Thousand Plateaus: Capitalism and schizophrenia. Minneapolis, University of Minnesota Press, 1987: 317. ] idea of the refrain, an element of rhizomatic structure also discussed by Deleuze and Guattari. They state that the refrain “organizes a limited space around a center in order to keep “the forces of chaos” outside as much as possible” [ibid]. In detritus the score always commences from the same point, a distinctive passage lasting about 10 seconds. At the conclusion of this passage the pathways trifurcate and continue to progressively proliferate. The structure emerges as a consequence of the repetition of this process for different periods of time (between 19 and 145 seconds), allowing a variety of pathways to be charted.
In this way the consequence of the rhizomatic score structure can be emphasized through the exposition of diverse outcomes originating from the same starting point. The use of a Refrain acts against what Deleuze and Guattari would call the ‘deterritorializing’ effect of indeterminate movement through the rhizomatic score structure.
Each performer in detritus has separate parts. The parts are horizontally (temporally) coordinated in the fashion typical of traditional music. This means that when the performers move together their parts are audibly more synchronized than when they are independent of one another. The semantic graphical score was assembled using rhythms and pitch contours from fragments (detritus) of a traditionally notated ensemble piece, cities sunk in endless slumber  for violin, clarinet and piano.
trash vortex takes something of an inverse approach: each part eventually converges upon successive nodes in the rhizomatic score. As the pathways taken from one node to the next vary in duration, each player pauses once a node is reached, “hovering” there until all players have joined them. Tracking the trajectories of each player allows for electronic processing to reinforce the stasis of successive players through emphasis on spectral manipulation of their sound. This structure might be termed a ‘Convergent Nodal’ form, and is a unique implication of rhizomatic structure.
A number approaches to frequency tracking were explored: manual frequency tracking, by annotating the spectrogram with multiple function objects and then retrieving the data by inputting the position of the audiofile as reported by snapshot~ to control the centre frequency of bandpass filters (Figure below); Automated frequency tracking controlling the bandpass filters’ centre frequency via frequencies derived from spectral anaylsis conducted using the sigmund~ object; and “ecological niche” tracking drawing on Krause’ theory which asserts that “animal and insect vocalisations tend to occupy small bands of frequencies leaving “spectral niches” (bands of little or no energy) into which the vocalisations (fundamental and formants) of other animals, birds or insects can fit.” (Wrightson, K. 2000. “Introduction to Acoustic Ecology”. Soundscape-The Journal of Acoustic Ecology, 1(1), pp. 10-13. p. 11).
Manual frequency tracking by annotating the spectrogram with multiple function objects to automate the centre frequency of bandpass filters.
Perhaps unsurprisingly then, the manual method for frequency tracking proved to be the most effective of those explored.
It could be argued that manual designation of the band pass frequencies adds a ‘human’ layer to the process in contradiction to the eco-structural aims of deriving all data from the environment itself. However, the process is no less of an intervention than choosing sonic features to be emulated by acoustic instruments and indeed, in this case, was achived through similar means: visual detection of features from a spectrogram. The approach is perhaps analogous to the ‘Cocktail Party Effect’ (Pollack, I. and J. Pickett. 1957. “Cocktail Party Effect”. Journal of the Acoustical Society of America 29 p. 1262) a feature of the human auditory perception in which conscious auditory attention allows for pre-semantic attenuation of signals in a complex environment.
Lyrebird allows for interaction with pre-recorded non-anthropogenic sound environments. The degree to which an interaction is meaningful is self-evidently dependent on the performer(s) abilities. Examples of this work can be heard at (https://lindsayvickery.bandcamp.com/album/works-for-instruments-and-field-recordings). However, unlike many musical experiences the potential for precise synchronisation of a performer with seemingly indeterminate sonic events arguably has an intrinsically interesting quality. The evaluation of the accuracy of performer emulation is something of an end in itself, and this includes both the degree of acoustic reproduction of the sounds (as demonstrated in the figures above) and the performer’s ability to “enter into” the soundworld of the recording through improvisation.
Nature Forms II (2015) explores the possibility of recursive re-interrogation of a field recording through visualization and resonification/resynthesis via machine and performative means. In Nature Forms II a range of forms of representation are used including semantic graphical notation, percussion notation and a hybrid form of sonogram notation. This most literal form of representation is the process I have previously termed the “spectral trace” in which notation is drawn directly onto the spectrogram to represent features of the field recording to be performed by an ensemble of flute (orange), clarinet (red), viola (green) and cello (blue).
“Spectral Trace” notation from Nature Forms II
The graphical symbols are presented on a proportional staff created to solve the problem that horizontally, the spectral trace is temporally proportional and performing with precision can be achieved through a scrolling score, however it is also vertically proportional – each pitch occupies a distinct vertical spatial position.
Subtractive synthesis was also employed by using frequency and amplitude detected in the recording to bandpass white-noise. At the opening of Nature Forms II “coloured noise” performed by the instrumentalists is gradually shaped into the sonic structure of the field recording using subtractive synthesis, and then cross-faded with the source recording.
Nature Forms II explores the notion of eco-structuralism, maintaining what Opie and Brown (2006) term the “primary rules” of “environmentally-based musical composition”: that “structures must be derived from natural sound sources” and that “structural data must remain in series”.
The structure of the original work is conserved using the approach discussed in the miracle of the rose, where the temporal proportionality of the recording is retained by aligning multiple notation and resynthesis versions of the recording in visual representations that can be alternated or combined in the creation process of the score, processing and fixed media.
The work also uses “spectral freezing” of components of the field recording to create spectrally derived chords from features of the recording bird sounds and a rusty gate which are then transcribed into notation for the instrumentalists and temporal manipulation of the recording to allow complex bird calls to be emulated in a human time-scale.
Visual representation of temporally proportional alignment of multiple resynthesis (a.- e.) and notation (e. – h) versions of the recording in Nature Forms II (excerpt): a. field recording spectrogram; b. additive synthesis spectrogram; c. ring modulation resythesis spectrogram; d. subtractive synthesis spectrogram; e. spectral “freeze” sonogram/score f. “lyre- bird score; g. “semantics of redaction” score; and h. “spectral trace” score.
Recording generated with data from the source field recording using additive, subtractive and ring modulation resynthesis.
to commemorate the 50th anniversary of Varésè' death a work was created using the composer's percussion work Ionisation as a source. Apart from alluding to the origin of the piece from the residue of a Varésè work, the title uses terms from particle physics which perhaps bear the same "fantastic" qualities in our own time that the term ionisation did in 1931.
In theory residual drift could be performed in conjunction with a performance of the source work. A sonogram of a recording of Ionisation was used to generate a score and accompanying pre-recorded electronics. The image of the sonogram was rendered in illustrator focussing on the range of the bass flute C2-around C4. Because sonograms are probably least effective at visualizing percussive works, features such as snare drum rolls appear as continuous pitches. This deficit was put to use in transforming Ionisation into a score for a solo instrument that makes its sound through "continuous" (as opposed to discrete) actions. The first few seconds of the Ionisation sonogram and the score of residual drift are shown below (note the "piano roll" style pitch indication is used as a "playhead" for the scrolling score to orientate the performer.
between-states audio sonogram (detail)
score created in Finale from MIDI-annotated sonogram (detail)
Unfortunately in this case I was unable to develop a satisfactory accommodation between the degree of detail in the score and the scroll-rate required to read it: if it was over-detailed it had to move too quickly to accurately read. For the first performance a simplified sonogram score (below) was used with a pitch-guide fixed at the left of the page. The pitch-guide replaced the single-line "playhead" that is used in most scrolling scores in the Decibel Scoreplayer. I had used the same approach to read Percy Grainger's Free music in the mac version of the score player (and this had later been coded into the iOS version by Aaron Wyatt. The pitch-guide had the advantage of providing more detail to the performers more "morphological" information about the sonic shapes and could also be scrolled more slowly than a conventional score. However in this version each player was allowed to choose which shape they would render with their instrument.
simplified sonogram score (detail)
The (possibly) final version of the score identifies sounds to be performed by each performer (bass flute - red, bass clarinet - green) and contains text annotations and hue variations to represent different timbres. Since the parts are more defined the full (unsimplified) sonogram is able to be re-added giving the performers a greater indication of the context in which their sounds are heard.
annotated sonogram score (detail) "pitch-guide" to the left