A continuously receding Horizon

Materiality and Unmastery in feedback practices

Article by Adam Pultz Melbye
In this article, I describe my ongoing artistic concern with resistant and asymmetrical musical instruments, as well as with the particular performance ecologies that emerge when using these instruments. I discuss the development of an acoustic musical practice and how this has lately translated into one evolving around the creation of feedback instruments and works. In this process, the role of matter in the emergence of the musical work has become increasingly apparent, as the feedback phenomenon causes the physical properties of the instrument to engage in complex relationships with—and engender—the creative process. Accordingly, the problematic nature of an overly narrow understanding of information flows becomes clear, making a case for embracing the messy and multi-directional reality of feedback environments, rather than trying to control them. Seen through the lens of decolonial and queer theories of unmastery and failure, I argue that feedback practices, being enmeshed in the self-organising and reconfiguring of matter, foregrounds the precarious and vulnerable ecology of performance. As such, it allows for the development of feedback aesthetics that acknowledge and explore the dynamic materialities of the work.
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Why are language and culture granted their own agency and historicity, while matter is figured as passive and immutable or at best inherits a potential for change derivatively from language and culture? (Barad 2007, 132)


In February 1998, I was a 17-year-old electric bass player, playing in rock bands but getting into jazz and dreaming of owning a double bass. Acting on a tip that an instrument was for sale at a music school two hours from my home, my father and I drove to inspect it. Having no idea of what to look for in a double bass, I could only ascertain that it had no cracks and was made of solid wood. Upon our return home with the instrument that afternoon, I embarked on a journey of technical and sonic engagements and investigations that now, 23 years later, is still occupying my time in due measures of excitement and frustration.
During my initial endeavours at learning the instrument, it became apparent to me, that, despite the decent quality of the bass, the many years of standing/lying/falling over in a music school had taken its toll on the instrument’s setup, most significantly the bridge, which was horribly warped and for some reason unreasonably high, lifting the strings far off the fingerboard. Accordingly, the instrument was difficult to play, requiring much effort in both depressing and plucking the stiff steel strings, and I pity the students who must have struggled to get any acceptable sound from this unwieldy beast. While suspecting that a better setup and a new bridge might have eased my hardships, living in the countryside, I knew no other double bass players and as such had no physical or social reference against which to measure my struggle.
In the early days of jazz double bass playing, amplification was largely unavailable and as such, bass players relied on the empathy of fellow musicians as well as on specific instrument setups in order to be heard. The action of the strings, that is, their distance to the fingerboard, was often significant, requiring strong hands, while at the same time being mediated by the relative flexibility of the then ubiquitous gut strings. The resulting sound was often percussive, creating an intersection between harmony and rhythm which was useful for driving a big band, but which also posed certain obstacles to the fluid execution of melodic lines. Two technological advances changed the situation: the introduction of piezoelectric transducers for amplification allowed bass players to lower their action and still be heard, while steel strings afforded increased sustain and pitch clarity, heralding an explosion in fast-paced and smooth virtuosity. Due to my limited exposure to other double bass players at the time, I was largely unaware that the setup of the bass I had just purchased straddled the history of jazz by combining modern stiff steel strings with what was then considered an archaic action much too high for contemporary bass playing. Rather than changing the setup, and due to equal parts of ignorance and stubbornness, I devoted my time to overcoming the physical resistance of the instrument and at the same time became skilled in blister management. By the time I entered the academy of music a few years later and was advised by my teacher to lower my action, the damage was already done: I had assimilated the resistance—and sound—of the instrument into my musical practice. Despite several attempts at reverting to a sensible setup, whenever the instrument became easier to play, and I was able to assume the role of a virtuosic bass player, as expected by some teachers and fellow musicians, I experienced a lack of physical engagement with the instrument and the music, not to say a discomfort in the lowering of acoustic output, requiring me to play with an amplifier. With an increased ease of playing, the sound of the instrument changed dramatically: the acoustically loud, rich and spectrally complex thud of a tense string transferring its energy to the body of the double bass gave way to a sustained and almost sinusoidal sound displaced from its origin through the intermediary of an amplifier and speaker. In frustration, I then raised my strings, and the cycle started all over again. It took me a decade to accept that my struggles originated in a disjunct between the affordances of my setup and what was expected in this particular style of music, rather than a failure on my part to practice enough. By adapting my practice to the material constitution of the instrument, its peculiarities, becoming habitually embodied in my sensorimotor skill sets and responses, ultimately shaped the domain in which music took place. In manifesting as potential as well as limiting condition for sound-making, matter came to co-constitute what Simon Waters (Waters 2007, 2021) and John Bowers have termed the performance ecosystem, that is the socially, historically, materially and technologically distributed situation of music-making. In the context of such an ecosystem, the question remains how, and if, to resolve the conflict between the internalisation of the material affordances of the instruments and the externally imposed demands of style and convention.


Like all technologies, musical instruments are embedded in complex networks of production, transmission, and reception and, like many of my peers, I was trained to master a tradition. In this context, my double bass was expected to physically perform similarly to any other jazz double bass. Additionally, the instrument was assumed to be the expressive vehicle of the musician, the intent of whom, in turn, constituted the real-time expression of the jazz tradition as it has developed and manifested since the early 20th century. This musical hylomorphism, that is, the notion that instruments are material vehicles of immaterial properties, while alive and well in institutional pedagogy, also resonates more broadly with the assumption that instruments interface with the world in a way that channels musical expression from a place of origin towards a receiver. As an example of this, we may consider the full title of the NIME conference: New Interfaces for Musical Expression.
However, the notion that the instrument is a mediator of intent runs the risk of reducing it to a passive agent in a unidirectional flow of sonic information travelling unchanged from sender to receiver. Although it has been consistently and convincingly challenged in the past decades (Stapleton and Davis 2021; Waters 2021, 2007), this notion stubbornly persists. To better understand why information can only in certain cases be conceived as decoupled from its propagation, a detour into communication theory is in place. I hope to show that musicking1, in being a physical practice engaged and entangled with matter, cannot be understood through the sender-carrier-receiver model that has propagated into popular thought.

Shannon’s theory of Information

The American mathematician Claude E. Shannon’s paper A Mathematical Theory of Communication (Claude E. Shannon 1948), which sparked the study of Information Theory, suggested a decoupling of the transmission of information from its semantic content. Along with work by the cyberneticist Norbert Wiener (Wiener 2019), Shannon revolutionised communication theory and established the groundwork for efficient data compression algorithms. Shannon’s model of information makes a few assumptions: firstly, it assumes that information transmission is a one-way street and secondly, that any interference in the signal is noise and, as such, should be filtered out. In the context of Shannon’s paper being a mathematical theory of communication, N. Katherine Hayles points out that “this was an appropriate and sensible decision” (Hayles 2000, 54). However, “Taken out of context, the definition allowed information to be conceptualized as if it were an entity that can flow unchanged between different material substrates” (ibid). As Hayles proceeds to point out, Shannon himself was aware of the limits of the applicability of information theory, to the extent of publishing an editorial with the suggestion that “… it has perhaps been ballooned to an importance beyond its actual accomplishments” (Claude E. Shannon 1956, 3).
With the subsequent development of second-order cybernetics2, noise became elevated to a fundamental property of self-organising systems (Von Foerster 2003, 1-19). Rather than being a nuisance, the introduction of entropy into a system allows the system to explore states unavailable under conditions of increasing order. The stable-state equilibrium studied by, amongst others, William Ross Ashby (Ashby 1957, 2014), gives way to an occupation with metastable systems that do not reach a point of rest, but instead oscillate between several attractors. Using case studies from the field of literature, Hayles makes an argument for the extent to which Information Theory and cybernetics have contributed to the disembodiment of information through these disciplines’ focus on the transmission of information, rather than on information itself. It is not difficult to see how similar considerations might apply in the field of music, possibly most obviously by considering the transition from the social practice of performance to the dissemination of music through analogue recordings and now, digital streaming and download (the existence of which incidentally relies on compression algorithms originating in Shannon’s work on redundancy in information encoding). More fundamentally, Hayles’ critique can be applied to a discussion of what constitutes the musical work in the first place, the role of the material in general, and instruments in particular. If, following Hayles, and even Shannon himself (Claude E Shannon 1956), the transmission of information can only be considered decoupled from its content in certain cases, we may ask which implications arise in the case of the transmission and communication of music. Is music simply a code that, at best, flows unperturbed from sender to receiver? Can we meaningfully talk about interfaces for expression in the sense that what is expressed somehow exists prior to the transmission itself, as if the transmission is decoupled from its material situatedness?

The Materiality of Sound

I would here like to focus on the immediate materiality of sound, that is, the physicality of transmitting and transducing vibrations in matter and air. Consequently, I will return to my own experience of playing a resistant double bass: while struggling to accommodate my playing to my own and others’ expectations of what a modern jazz double bass player should do and sound like, and going through numerous instrument setups and string brands, my musical practice increasingly became informed by the European scene for experimental and improvised music3. This shift from a strictly defined role in a group hierarchy to a tradition that accommodates a more fluid understanding of each instrument’s role and, not unlike early jazz4, affords the exploration of extended techniques and preparation of instruments, allowed me to explore my idiosyncratic setup as a way of facilitating a spectrally rich sonic environment that relied on the physical constitution of the instrument itself as a generator of musical material5. I had previously attempted to channel a specific musical tradition through an instrument that, with its idiosyncratic physical constitution, could only accommodate such an endeavour with difficulty. Now, when working in an improvised and stylistically less rigid domain, I was at greater liberty to explore the instrument, not as a channel of the transmission of information in the shape of stylistic code, but rather as a co-constitutive node of generation.
In other words, instead of attempting to purge information of the noise introduced by its carrier, by situating my playing within the context provided by the physically resistant constitution of the instrument, allowed for the emergence of a music previously unavailable to me. In this process, information transmission became dirty; it became lossy and additive at the same time, problematising the cybernetic notion of information, that, possibly somewhat unintentionally, has become a popular notion. While what is received, from the point of view of the listener, may be said to originate in a sender, at any point during its transmission it may become modulated by the channel itself. Rather than a packet of information with a single point of origin, the signal itself becomes a product of its transmission. From this point of view, reducing music to human agency expressed through representational systems such as notation, form schematics, or as re-enactments of the past, underestimate that the configuration of matter that comprises an instrument is co-constitutive of the musical work itself. There can no longer be a question of decoding the musical message as if it existed as pure intent prior to its actuation. 
    In advocating for substituting the notion of form with that of information, Gilbert Simondon warns that ‘the notion of information must never be reduced to signals or supports or vehicles of information, as the technological theory of information tends to do when it is siphoned by abstraction from the technology of transmissions.’ (Simondon 2020, 16). String manufacture and action, the tension and thickness of bow hair, wood, air humidity, and so forth, rather than merely supplying the form for primordial musical content, are transductive phenomena in the Simondonean sense: they are generative as well as transformative of the musical work itself. Steel and gut strings, through the difference in their material composition, do not carry identical information. But more importantly, neither carries the ‘right’ information. As sonic carriers, they are also modulators. Hence, the information and the music produced is a function of their reciprocal relationship with a sender, the musical intent of whom is shaped by an embodied and material situatedness.

The Apparatus

Similar to a criticism of the decoupling of information from transmission, we find Karen Barad’s discussion of the discursive, semiotic, interpretative, and cultural turn. In arguing that the representationalism that these notions rely on runs the danger of favouring language at the expense of the dynamism of matter (Barad 2007, 133), Barad concludes that ‘the only thing that doesn't seem to matter anymore, is matter’ (Ibid, 132). With the entanglement of matter and meaning being a central tenet in Barad’s work, I believe that their use of the term apparatus can help untangle the relationships between instrument and work, especially in the context of musicking. Barad’s discussion of the apparatus emerges from their analysis of Niels Bohr’s Gedanken experiments, in particular his occupation with understanding the role of the experimental apparatus. Barad points out, that where Bohr’s introduction of ontological indeterminacy into the measurement of quantum phenomena went further than Werner Heisenberg’s epistemological uncertainty, the physical boundaries of Bohr’s measurement apparatus were assumed to rely on the observational agencies of a human observer (Barad 2007, 143-144). In contrast, Barad argues that the apparatus not only measures but partakes in the constitution of the phenomenon being measured. In other words, it is not that the act of measuring obscures some underlying and pre-existing reality. Rather, in Barad’s agential realism, ontologically speaking, reality comes into existence through intra-action, in which distinct agencies emerge, rather than precede, their process of constitution (Barad 2007, 33). Barad’s proposal, that we understand apparatuses as phenomena in themselves, that is, in a process of constitution and dynamical reconstitution (Ibid: 146) affords an attractive context in which to understand the musical instrument in particular, and the materially situated performance ecology in general.
Whether one subscribes to Barad’s strong ontological claims regarding the measurement problem and the constitution of reality (Schaffer and Lemos 2021), the understanding of the apparatus as being entangled with what is measured coincides with the notion that the instrument is co-constitutive of the emergence of the musical work, and vice versa. Intra-actively speaking, instrument and music are not discrete entities or agencies; rather, they only become distinct through their mutual entanglements. As an apparatus, the instrument does not channel. In contrast, through its material nature it is intimately joined with the act of musicking to the extent that the discrete meaning of both instrument and music emerges in their co-constitution.

Feedback and Materiality

Feedback6, I believe, presents a strong case for situating musicking within a context that profoundly engages matter while exploring modes of asymmetry and resistance. In the past three years, I have explored various feedback systems, lately focusing on the development of the FAAB (feedback-actuated augmented bass)—an instrument discussed in greater detail below. Through the ongoing work with the FAAB and other feedback systems, I have come to regard these practices as fundamentally related to my initial and ongoing explorations of the acoustic double bass as a resonant, sonically complex, and resistant phenomenon. While relying on the deceptively simple mechanism of amplifying something through itself, feedback affords the establishment of intimate relations with—and explorations of—diverse material configurations and relations. In addition to such classic works as Alvin Lucier’s I am sitting in a room (Lucier 1990) and David Tudor’s Rainforest (Tudor 1998), the current issue of the Echo Journal contains several examples of such configurations and the extent to which their material situatedness determines the identity of the work (Brandtsegg 2021; Di Scipio 2021; Van Horrik and Dubach 2021).
Precisely through the iterative nature of the feedback phenomenon, matter is both actuated and engaged, as well as actuating and engaging. In a sense, with feedback, matter haunts itself. While this is the case for any resonant object that continuously, but not instantly, dissipates its energy to an environment, feedback systems occupy a special position through their operational closure, which allows for a certain amount of the supplied energy to recirculate within the system itself. As will be discussed later, operational closure does not equate to sealing off. Rather such closure is dependent on environmental couplings, presupposing a construction of, and engagement with, a world (Melbye 2021, 23; Varela 1991).

In Ashby’s An Introduction to Cybernetics, we find a function describing the disembodied notion of feedback (Ashby 1957, 53):

As Ashby notes, this simple function is of interest to cybernetics because the value of x will change that of y, and vice versa. While Ashby and other first-generation cyberneticists’ occupation with formalising a theory of feedback laid the foundation for rigorous studies of control systems, as with information theory, the disembodied nature of the concepts evolved, risk sacrificing the messiness of the real world to a mathematically precise, yet highly specific description. Whether Ashby and Wiener were fully aware of this danger, Ashby does point out that feedback, in itself, is inadequate for describing the general principles of dynamic systems (Ibid, 54). Additionally, numerous devices built by early cyberneticians, such as Ashby’s own Homeostat (Ashby 2014, 100), Grey Walter’s Tortoise (Pickering 2011, 41-51), Shannon’s mouse (Hayles 2000) and, in particular, Gordon Pask’s numerous devices (Pickering 2011, 313-321, 325-341, 353-361), testifies to an occupation with practice as well as theory. In the domain of our current concern, that is, audio feedback systems, complex relationships never manifest in an idealised neutral substrate and as such, only with great difficulty can be reduced to simple recursive functions.


The concern with the fashion in which the phenomenon of feedback engages matter consistently manifest across artistic practices, the articles in the current journal issue being no exception. As such, they stand in stark contrast to the disembodied notion of feedback described above. As examples, we may consider Scott McLaughlin’s feedback clarinet (McLaughlin 2021) and Øyvind Brandtsegg’s report on the practise of acoustically coupling a microphone to a speaker through aluminium tubes of various lengths in order to induce complex pitch relationships (Brandtsegg 2021). On a historical note, as well as related to the latter example, the Larsen tone generator—built in 1911—consisted of a speaker and microphone coupled through tubes of adjustable length (Kjerbye Nielsen 1984, 141). Here it is worth noting, that Larsen’s tone generator was conceived in response to feedback couplings between earpiece and microphone in early telephones: the material configurations of communication technology facilitated the earliest theory of audio feedback and the development of one of the world’s first pure-tone oscillators.
Matter does matter. It matters which speakers we use, in which material they are embedded, what tubes are made of, and the stability of the soldering—properties that are accentuated and, in some cases, altered through their participation in the recursive network. In a linear system with a unidirectional signal path, resonant frequencies of tubes, speakers, microphones, the room, and so forth will affect and colour the sound produced. In a feedback system, these properties tend to define the baseline behaviour by forming attractors in the phase space of that system—that is, by creating strong resonant potentials toward which that system may develop. As the amplitudal saturation of the system increases to the point of self-oscillation, the material, and the signal fold in on each other, occluding both the carrier-information—as well as input-output binaries. Matter becomes engaged as well as engaging, establishing a tightly coupled and interdependent relationship with the energy of the system, exposing material properties unavailable, or only fleetingly available, to the non-self-oscillating system. These properties, however, are not necessarily fixed, waiting around to become actuated by the Larsen effect; rather, they are emergent and non-linear phenomena produced in the interaction between multiple material nodes in the network and the energy flowing through it. As such, they are mutable and reconfigurable entities. The material configuration of a feedback system, then, bears similarities to Barad’s notion of the apparatus: it partakes in the enaction of phenomena rather than being the channel through which a signal passes, and as such constitutes the inseparability of the object and the measuring agencies (Barad 2007: 139). The challenge posed to the notion that Shannon Information can be applied broadly becomes apparent here: the work, rather than a preconfigured package of information waiting to be shipped over a low-noise channel, emerges in the iteration and reconfiguration of matter(ing) (for a discussion of the term ‘mattering’, see (Barad 2007, 180)).

How feedback matters

As previously observed, in the context of an acoustic performance practice, the specifics of the material assemblage are essential to the establishment of musical identity and not exclusive to feedback practices. In fact, because acoustic instrument and feedback networks both rely on operationally closed resonant structures, they share similarities perhaps obfuscated by the fact that their designs belong to different periods of history and embody different technologies. Nonetheless, the coupling between the acoustic double bass body, bridge, and strings, as well as the density and quality of the wood of the instrument contribute to the establishment of vibrational feedback manifesting as acoustic resonance. In the feedback system, the continuous supply of a significant amount of energy, allowing for resonant build-up even when not engaged by a performer, is what sets the two systems apart. Contrastingly, an electric bass mainly relies on the amplification of a unidirectional signal path between string and amplifier, often taking place in a solid and somewhat acoustically inert body, although even here, some degree of resonance manifests.
Feedback is to some extent found in all acoustic instruments, with differences between these and their electric siblings manifesting along a continuum, rather than as discrete domains. However, a significant difference may be drawn at the point where the resonance of a system exceeds a tipping point to cause continuous self-oscillation. Unique to the stronger closure of the positive audio feedback loop, the material returns to haunt itself. Its physical constitution defines and imposes a domain of interaction that, with each iteration, is narrowed to ultimately manifest as resonance. However, whereas good acoustic instruments are built to afford a high level of sensitivity to the fashion in which they are actuated, and the energy supplied to them is bound by the physical capabilities of the performer, feedback systems do not automatically exhibit this sense of criticality across all amplitude ranges. Short of causing system breakage, a high-gain feedback loop will settle into the system’s strongest attractor, or path of least resistance, causing the shift from a meta-stable to a stable state, and ultimately limiting the freedom for the system or performer to explore multiple attractors in its phase space (Kiefer, Overholt, and Eldridge 2020, 343). As such, feedback is not a magic wand that may reveal the material under any given condition. Rather, the energy introduced into the system must be matched to the carrying capacity at which it can operate in a metastable state, which, in turn, is a function of its physical constitution. For the performer, the feedback system as such must operate within a delicate domain of criticality (Bak 1996), the collapse of which would mean the loss of variety and possibilities for adaption.

Individuation in metastable Systems

As an apparatus, the feedback system is a measure and modulator of the material, not only gauging the latter’s physical constitution but actively engaging in the genesis of what is being measured or observed, in effect creating the sonic work. Through its measuring agencies, the apparatus affords a way of knowing this work, not as something existing prior to—but instead as unfolding through knowing. This knowing-as-becoming constitutes processes of individuation, which, in Simondon’s terms, describe the transductive operation through which “matter has taken form in a certain system of internal resonance”, establishing a being as itself (Simondon 2020: 32). Simondon proceeds by specifying that “Individuation as an operation is not linked to the identity of a matter but to a state modification” (ibid, 70). However, if we, with Barad, stress the active nature of matter through its dual property of being a noun as well as a verb—that is, the mattering of matter—we may see individuation as ongoing articulations of the material, or as the realisation of potentialities within this material. To Simondon, potentiality is what allows for becoming, which he considers “the being’s dimension” (Ibid, 4) in which individuation is a resolution manifesting in a system that entertains a “certain incompatibility with itself” (ibid). According to Simondon, this liveliness of matter in its process of individuation was thought inconceivable by the Ancients, through their exclusive knowledge of stable-state equilibriums. In contrast, individuation, being a feature of systems in a state of potentiality (ibid, 57), presupposes metastability (ibid, 70). That is, the system exists in an intermediate state between stable equilibriums and, as such, is not completely actualised but rather in a process of self-organisation. In the metastable feedback system, mattering manifests in the relationships between physical nodes (speaker, pickup, microphone, amplifier, body, etc.) and their properties (curvature, shape, density, etc.), allowing the ongoing individuation of these nodes while retaining their entangled state with and within the overall system. Performing a feedback work, one is in a continuous process of establishing relations with matter in its ongoing reconfiguration, negotiating the individuation of materials across global systemic, as well as local, levels.

The emergence of resonant frequencies, complex spectra, amplitude swells, and so forth may not always be immediately traceable to individual parts of, or relationships within, the system. Nonetheless, these phenomena demand an engagement similar with that of playing an acoustic instrument: in order to facilitate a musically cohesive performance, a certain level of familiarity with the instrument allows for an ongoing exploration of its properties and hence the establishment of a musically cohesive practice. Such a practice does not rely on a conscious engagement with the specifics of the system, but rather favours an embodied and intuitive approach to interaction. This non-specificity goes both ways: with the feedback system operating in a metastable state, such engagement, rather than directing the system toward any obviously causal response, becomes a perturbation, triggering adaptive and self-organising processes, the result of which may embody some of the performer’s intent, but may also have global consequences far beyond the reach of any predictive capabilities on the part of the performer. As I have described elsewhere, the precariousness of this asymmetrical relationship between performer and instrument affords a level of improvisatory music-making mostly found in social musical practices involving other human performers, and as such, raises questions of distributed agency (Melbye 2021, 25-27).

Acknowledging the differences between acoustic instruments and contemporary feedback systems, there is still a sense in which the double bass setup I chanced upon at age 17 and the perplexing behaviour of feedback systems share certain features that encourage ongoing exploration. In my acoustic as well as feedback practice, this domain of exploration emerges through the asymmetry established between the performer’s intent and the response of the instrument. While this asymmetry, in the case of the feedback system, may be engineered through adaptive algorithmic approaches (Úlfarsson and Melbye 2020), the specific material configurations of the system play their own part in the establishment of its identity, and hence its differentiation. Asymmetry, manifesting as a sense of resistance from the performer’s point of view (Melbye 2021; Stapleton 2008) is a way of the material making itself known: rather than the idealised interface for musical expression, matter manifests itself through irreversible processes that don’t just shape, but co-constitute what is being said, in a process that may sometimes feel like a welcome complexification of performative intent and at other times a bewildering obstruction.

The FAAB: a feedback Apparatus

While I have always cherished this feature of an acoustic instrumental practice involving an instrument set up for asymmetrical interaction (Melbye 2021), nowhere in my practice is this more apparent than in my work with the FAAB (feedback-actuated augmented bass)7. Being a vibrotactile feedback instrument featuring pickups, a microprocessor, amp and a built-in speaker, the string feedback of this instrument is a summative, rather than additive, nonlinear function of its discrete material components.

Enforced by the vibrotactile feedback loop, the auto-haunting of matter is expressed through the high non-linearity of responses across the playing range of the instrument. At certain locations highly responsive while at others completely dull, vibrational reinforcement and cancellation generate resonances and anti-resonances through the interactions of the speaker, instrument, body, bridge, strings, embedded microprocessor and so forth. As such, the material constitution of each of these components assumes central significance. It matters what the speaker is made of, which string brand I use and whether the bass is carved or made of plywood, as any and all of these details, through the feedback, contribute toward determining the phase space, that is, the domain of possibilities, and hence, the possible musics. Even in the case of something as apparently virtual and ephemeral as code, the placement and suspension of the microprocessor underneath the fingerboard, and the fact that it will occasionally touch the body of the instrument, dampens and alters vibrations. Additionally, the necessity for keeping electronic components at a small size to accommodate self-contained design-goals of the FAAB, places restraints on their physical constitution and efficiency, setting specific ceilings for sample rates and bit-depths. This, in turn, directly influences signal-to-noise ratios and the resolution of the signal processing.
Being a new and cheap plywood instrument, the first iteration of the FAAB afforded certain modes of interaction through the slowness of its response. The most recent FAAB, being an augmented carved instrument of decent quality, equipped with a more powerful amp and a speaker with a greater frequency range, has a quite different response that feels quicker and more immediate. However, applying notions of quality to the comparison between these two instruments is a difficult task: precisely because the instrument is not an interface for musical expression, but an apparatus invested in the emergence of the musical work, the standard against which we measure phenomena becomes a function of those very phenomena. In the words of Lucy Suchman: 'what was talked about itself extended what was talked about, providing a continuously receding horizon of understanding to be accounted for' (Suchman 2006, 66). In comparison to the fast response of a high-powered feedback signal travelling through a carved instrument body, a sluggish plywood instrument with a slow response may in some cases offer more room for exploration of unintended and accidental outcomes, the result of needing to push the instrument harder to elicit responses and change. In either case, the material is anything but mute. Rather, it co-enacts the rules of engagement and situates the performer in an ecology with a continuously receding horizon in terms of engagement as well as evaluation. As such, the previously introduced notion of instrumental resistance may seem unfit: implying a (however ill-defined) duality between performer and instrument, such boundary-drawing, in the current case, runs the risk of reintroducing hierarchies of intent. While performer and feedback system, in their individuation, can be considered operationally closed, such closure implies the thermodynamical and informational coupling—and hence openness— to environments and other bodies (Di Paolo, Buhrmann, and Barandiaran 2017, 115). Being a feature of metastable systems, this individuation is ongoing and open-ended. Consequently, in the emerging epistemology of materiality in feedback practices, we should be careful to not allow such terms as resistance to reinstate the human at the centre of an ecology, the entangled materiality of which suggests that what may be at play can better be described through the notion of interactional asymmetries between individuating and individuated phenomena.


However, such an epistemology does not entail the impossibility of developing and refining performative relationships with metastable feedback systems, or any system for that matter: the process of practicing and exploring an instrument, familiar to most musicians, applies just as well to the case of feedback systems, with the difference being the comparatively greater interactional asymmetry in establishing relations with the latter. Elsewhere, I have suggested the term diachronic mastery to describe the development of expertise in navigating precarious sensorimotor schemes in improvising with the FAAB (Melbye 2021, 25). While I am still fundamentally aligned with this reasoning, a materialist reading of the notion of mastery—even one that acknowledges the dynamic and precarious nature of human-instrument relations—suggests that the concept of mastery itself may be an impediment to fully exploring and realising the potential of the asymmetry inherent in human-instrument relations8. In discussing the acquisition of English as a second language, Julietta Singh questions the very notion of skill, maintaining that it is intrinsically linked to the “relations of power that make it possible” (Singh 2017: 92). While music-making operates at a different level of abstraction than language, its practice and tools are deeply entangled with socio-economic relations; from the power structures of the nation-state mirrored in the symphony orchestra to the herdsman playing his flute (Small 1998: 201). As such, it is difficult to imagine notions of musical mastery in the global North being disengaged from a colonial, capitalist and patriarchal past and present, obliging us to enquire which societal and cultural norms may be (unknowingly) perpetuated through practices of instrumental virtuosity. In my reading, Singh’s decolonial and dehumanist project of unthinking mastery, which calls on us to 'give ourselves up to wider and less hostile horizons' (Singh 2017: 90), resonates with Suchman’s receding horizon. It suggests that a feedback practice that profoundly engages with the material, through a practice of unmastery and vulnerable engagement (ibid. 91), may offer ways of making music that challenges human privilege and acknowledges relational asymmetry as a condition to be explored, rather than an impediment to be neutralised. Unmastery, then, becomes a practice of nurturing that asymmetry.

Reality through Failure

Writing these words, I am at the tail-end of an intense rehearsal period of a commissioned piece for a major festival for new music. Being a one-hour duo for vocals, FAAB and 12-channel signal processing, the pressure is on to deliver a significant work that will engage the audience and make the curators feel that their money and time was well spent, not to mention the labour we, the artists, invested in the work over the past five months. A certain section of the piece features an extended solo for FAAB, utilising string feedback in conjunction with bowing to create dense beat-frequencies. But whether due to the interaction between the acoustics of the new rehearsal space and the resonant frequencies of the FAAB, a recent re-soldering, change in climate, a ten-hour train journey, or possibly a cable touching a vibrational node on the instrument body, the domain of exploration I had familiarised myself with in the last rehearsal period is but a shadow of itself. Interference patterns no longer emerge as expected and I am sometimes left with static and uneventful sinusoidal feedback that seems to fit nowhere in the arc of the composition, or with the varied and texturally rich material of my collaborator. By having partly ceded control to a self-actuating apparatus, I am now in the philosophically interesting, yet musically terrifying situation of needing to ‘make it work’, that is, responding appropriately to the receding horizon of material reconfigurations. What is appropriate, then, becomes the question. Being coupled to the FAAB in a vulnerable and agentially opaque engagement calls for the abandonment of planned actions in favour of situated ones, the evaluation of which must happen in real-time. This coupling of a local— (human-instrument) to a social concern sets the stage for the possibility of what Suchman describes as effective encounters, that is, 'those moments of moving complicity between persons and things achieved through particular, dynamic materialities and extended socialities' (Suchman 2006: 245). In the present case, the extended socialities comprise a network of multiple human agents, instruments and machines, underlining the fact that evaluation of the effectiveness of the encounter is a distributed affair, even if confined to the human domain. In the case of musicking, the moving complicity of Suchman’s observation calls for an aesthetic plasticity that accommodates, on the one hand, the dynamic material nature of the work, and, on the other, its social situatedness.
Where does this leave me—the performer—facing the crowd in a reverberant 70-meter long space, with 12 speakers ensuring that every asymmetry and unmasterful engagement is reported in great detail and clarity? Contrary to the tightly controlled beat frequencies and interference patterns possible on an acoustic double bass (Melbye 2017), with the FAAB, there is often little certainty as to what will happen once the instrument is set in motion. In such precarious situations, the instrument-as-apparatus becomes a measure and mediator of the constitution of material configurations at any given moment and establishes relational asymmetries between instrument and performer. The impossibility of immediately absorbing any such asymmetry implies failure, but also paradoxically allows for an engagement that acknowledges Ernst von Glaserfeld’s observation that failure may be a way for organisms to meet their reality (Von Glasersfeld 2013, 156). Perhaps paradoxically, in a feedback practice that is a continuous rehearsal of asymmetrical relationships, the effective encounter may be the one that acknowledges this failure as a way of knowing that does not emerge from an external perspective of observation. Rather, such knowing exists in an entangled state with its subject. Here, in contrast to Heidegger’s tool-analysis, failure is not the notion of the breaking of a tool, rendering it unusable and hence present-to-hand rather than ready-to-hand (Heidegger 2008, 103). Failure implies the individuation of matter as it establishes itself in relation to a performer, and accordingly is an actualisation of a potential rather than breakage. However, as Jack Halberstam points out, we need not give in to a desire to relieve failure of its negative connotations (Halberstam 2011, 106). In failing to succeed, we are at liberty to not give in to normative ideas of musical mastery, virtuosity and success. Instead, we can remain in and explore the uncomfortable and troublesome liminal space offered by the metastable feedback ecology. This is echoed by Hillery Glasby who, from the point of creative writing, insists that ambivalence, although often being a marker of distress, can be invoked as a methodology that challenges the need for coherence and polished texts (Glasby 2019, 27-28). The ambivalent and metastable state, saturated with potentiality, may in fact be the most interesting place to be.


Elsewhere in this journal, Marcus Wale makes a case for why feedback, through its resistance to control and its risk of failure, presents a queer alternative to the often glossy and heteropatriarchal practice of glitch music (Whale 2021, 8). Wale’s argument, also referencing Halberstam’s notion of a Queer Art of Failure (Halberstam 2011) resonates with my understanding of, and desire to embrace the, at times uncomfortable, uncertainty accompanying the encounter with a reality in which matter challenges the notion of supreme human intent. Failure presupposes difference and asymmetry and as such, an individuation of phenomena, while creating a widening horizon of possibilities. But, like the notion of resistance, we should not let failure entail a dualist ontology of reductive subject-object relationships. Rather, it elucidates the fashion in which matter may make itself known in the context of feedback musicianship, to afford the development of vulnerable, ambivalent, messy and exciting ways of engaging with run-away musics. The receding horizons of these encounters may reveal new domains of exploration on several time scales—from real-time improvisation and navigation of (loosely) pre-determined structures to the development of new, and sometimes uncomfortable, aesthetics. Emerging from these encounters, such aesthetics can be unruly and, for instruments that rely on physically engaged practices, they are entangled with the performative aspects of the negotiation between player and instrument—that is, the very physical nature of sound-making. Embracing the physically messy, embodied qualities of engagement and negotiation, in other words, the drama of failure, affords encounters with reality, as already pointed out by Von Glaserfeld. Yet this reality is not the Kantian Ding-an-Sich: it is the enactment of a world unique to the present encounter and foregrounding the fact that matter, as hinted at by Barad, is indeed not passive and immutable—not a thing, but a doing (Barad 2007: 183). Experimental music and art practices traditionally have been deemed difficult to access for the uninitiated spectator, who may be left with the feeling that the experimental musician never got to the chorus (Roxette 1995). In contrast to the assertive structure of a fully composed work, may it be, that by engaging with the ambivalence and risk of failure that are the hallmarks of a metastable equilibrium, we can make ourselves vulnerable and open and hence establish a shared, intersubjective reality between ourselves and the audience? Such a reality would rely less on the transmission of a ready-made or fully conceived message and more on the communication of potentialities. It is my suggestion, that the practice of resistance, unmastery, ambivalence, and failure offers a way of defining a(n) (feedback) aesthetic that forefronts the dynamic materialities of the work, celebrating precarious and asymmetrical relations in creating an ecology of vulnerable encounters.


I wish to thank the anonymous reviewer for suggestions. I am very grateful to Isabel Bredenbröker, Simon Waters and Paul Stapleton for their invaluable suggestions and comments at various stages of the draft.


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31 January 2022
Review status
Double-blind peer review
Cite as
Pultz Melbye, Adam. 2022. "A continuously receding Horizon." ECHO, a journal of music, thought and technology 3. doi: 10.47041/DXGG9867


  • 1 Musicking—a term coined by Christopher Smalls—identifies music as a social activity, rather than as a thing or essence (Small 1998).
  • 2 Second-order cybernetics developed from the original discipline of cybernetics, with the realisation that the observer of the cybernetic system are themself engaged in a recursive and reflexive act of systems observing systems (Von Foerster 2003).
  • 3 Acknowledging the place of improvisation in most musical traditions, I am situated in a historical and cultural tradition of European improvised music, that, while differing from the American free-jazz tradition in certain aspects, is nonetheless deeply indebted to afrological musics (Lewis 1996).
  • 4 As an example, trumpeter Rex Stewart’s use of half-valve techniques, mutes, and vocalised growl sounds, as well as Baby Dodd’s drum setup and his development of the novel “shimmy beat”.
  • 5 The exploration of instrumental timbre and extended techniques is by no means exclusive to improvised music and I am not intending the claim that improvisation is somehow purer or superior to composed music.
  • 6 For an introduction to—as well as expert tutorial on—feedback, see Agostino Di Scipio's article in this issue of Echo (Di Scipio, 2021)
  • 7 https://www.adampultz.com/faab
  • 8 This of course pertains to our relationships with the world in general, but is beyond the scope of this article.

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