I started my studies in January 2019, planning to focus on how amplification and digital signal processing can augment and extend double bass resonance. Shortly before my studies started, the instrument designer Halldór Úlfarsson and I started a conversation about building a feedback double bass, following the principles of the halldorophone, which is a cello-like feedback instrument invented by Halldór. In April and June 2019, I visited Halldór in his workshop in Athens, where we retrofitted a double bass with pickups, amplifier, speaker and a microcomputer. By amplifying the strings of a double bass through the double bass body itself, the strings enter self-oscillation, or feedback. It is an exhilarating and slightly terrifying experience to engage with an instrument strongly vibrating on its own. However, once the initial concern over the structural integrity of the instrument had abated (no double basses were harmed during the study), I realised the significant creative potential of this instrument. The instrument has since been named FAAB (feedback-actuated augmented bass). A performance with the FAAB won Best Music Prize at the NIME (New Interfaces for Musical Expression) conference in Birmingham in 2020, and I have played numerous solo concerts with the instrument, online, as well as around Europe.

In the months after completing the design of the FAAB with Halldór, and as I began studying this unwieldy beast of an instrument, it became apparent to me that my PhD research would focus on this self-resonating double bass. My thesis is called A Continually Receding Horizon: Making, performing, and improvising with semi-autonomous double bass feedback instruments. The research is practice-led, meaning that a portfolio of performances and recordings constitute part of the thesis. Additionally, over the course of around 140 pages, I describe and discuss several works realised with three different feedback instruments, all build around the double bass. The main focus, though, is the development of a practice with the FAAB, which is now my main instrument. The portfolio documents a selection of solo and collaborative performances, while the written part of the thesis is a reflection on the work with the instrument, in addition to a theoretical exploration and discussion of string instrument feedback techniques. I also discuss human-computer interaction and improvisation in order to contextualise the development of a digital signal processing environment for the FAAB, that allows the instrument to achieve a certain semi-autonomy. In this context, I developed a software library (pultzLib) in the programming language C++. This library, as all my research, will be released as open-source, and is designed for instruments like the FAAB, hopefully useful to the growing community using feedback-actuated string instruments.

The last chapter of my thesis is a critique and discussion of the terms failure and mastery. I believe that playing semi-autonomous and “resistant” instruments such as the FAAB and other feedback interfaces may teach us valuable things about what we understand mastery, virtuosity, and failure to be. Here, I argue that traditional notions of mastery and control need to be re-evaluated in order to develop meaningful relationships to instruments that don’t always do what we want them to.

During my thesis, I have published two journal papers, co-published two conference papers, and guest-edited a special journal issue on creative feedback practices with the ECHO journal at Orpheus Institute at Ghent in Belgium. I have given numerous presentations and talks (many of these online) in the US, Australia, Denmark, Belgium, the UK, and Germany. My research is accessible at: https://www.researchgate.net/profile/Adam-Melbye