Black Box Communion
Trio, PPG Sensors, Live Electronics & Live Lighting (20 mins)
Black Box Communion constructs a network of feedback loops, where human bodies and technological systems mutually shape each other. The piece is based on the concept of a ‘black box’ – an opaque, algorithmic entity whose internal workings and processes remain unknown to the performers – which measures each musician’s pulse in real-time and uses it to generate light and sound.
The three musicians follow neither a conductor, a metronome nor a score, but the sounds of their own hearts projected back to them. Rather than synchronising, they coexist in adjacent but distinct temporalities, each shaped by their individual perceptual experiences.
This loop forms a ritual: the performers commune with a system that listens, transforms and speaks back. The lights and sounds triggered by these pulses create a shifting environment that responds to the body whilst also shaping its behaviour in return. The performer becomes both source and subject of their own musical and biological processes.
Black Box Communion was created as part of London Symphony Orchestra’s SoundHub programme for the 2024/25 season. Composers were invited to propose projects making full use of the LSO’s production facilities and technical support. I proposed a work building upon my previous experiments with PPG (Photoplethysmographic) sensors — particularly A Body Not Bound By The Same Limitations written for Ensemble Proton Bern in 2023 — in which performers’ heartbeats are monitored in real time and used as the basis for musical time.
In Black Box Communion, three musicians each wear a PPG sensor, their individual pulses translated into auditory signals and returned to them as pseudo-click tracks to replace traditional mensural timekeeping. As in my earlier pulse-based works, the outcome is a non-replicable performance environment in which three independent tempi coexist and fluctuate according to the performers’ physiology. Extending this concept further, the piece integrates live electronics and DMX lighting that respond directly to each performer’s heartbeat, creating an audio-visual field that is entirely reactive and alive to the moment of performance.
Rehearsing and composing the piece presented unique challenges due to the nature of its design. Each part effectively comprised of an extended count of heartbeats, with re-synchronisation occurring only eight times throughout the piece. This structure left the performance acutely vulnerable to physiological fluctuation, introducing both instability and the excitement of emergent, unpredictable musical relationships.
The compositional process demanded careful calibration to ensure that, despite its inherently variable duration, the piece would remain within a defined duration. Further complexity arose from accounting for the sensors’ natural inconsistencies and the performers’ physiological variability.
The musicians were exceptional collaborators throughout the process, contributing thoughtfully and meaningfully across multiple workshops and rehearsals. Their commitment and interpretative sensitivity were integral to the realisation of the work, but I would like to extend my heartfelt thanks to everybody involved in the project: Chihiro Ono, Colin Alexander, Michelle Hromin, Heather Roche, Aaron Einbond, Joyce Lam, the LSO concerts team and the LSO tech team.
In April 2025, I spoke with Patrick Ellis of PRXLUDES about Black Box Communion – https://prxludes.net/2025/04/21/hugo-bell/