This paper presents an overview of a human-machine collaborative musical performance by Raül Refree utilizing multiple MIDI-enabled pipe organs at Palau Güell, as part of the Organic concert series. Our earlier collaboration focused on live performances using drum generation systems, where generative models captured rhythmic transient structures while ignoring harmonic information. For the organ performance, we required a system capable of generating harmonic sequences in real-time, conditioned on Refree’s performance. Instead of developing a comprehensive state-of-the-art model, we integrated a more traditional generative method to convert our pitch-agnostic rhythmic patterns into harmonic sequences. This paper details the development process, the creative and technical considerations behind the final performance, and a reflection on the efficacy and adaptability of the chosen methodology.

This paper investigates GrooveTransformer, a real-time rhythm generation system, through the postphenomenological framework of Variational Cross-Examination (VCE). By reflecting on its deployment across three distinct artistic contexts, we identify three stabilities: an autonomous drum accompaniment generator, a rhythmic control voltage sequencer in Eurorack format, and a rhythm driver for a harmonic accompaniment system. The versatility of its applications was not an explicit goal from the outset of the project. Thus, we ask: how did this multistability emerge? Through VCE, we identify three key contributors to its emergence: the affordances of system invariants, the interdisciplinary collaboration, and the situated nature of its development. We conclude by reflecting on the viability of VCE as a descriptive and analytical method for Digital Musical Instrument (DMI) design, emphasizing its value in uncovering how technologies mediate, co-shape, and are co-shaped by users and contexts.