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1. TCP/IP: NIME
2. TCP/IP: Sestina
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3. Live Coding the Global Hyperorgan
© Mattias Petersson, 2025
When selecting a new part, a function defined in the SuperCollider class is run (see example below). This function sets the tempo, the play duration (in number of beats) for each new trigger, and a pattern that dynamically alters other parameters. Sometimes the velocity value coming from the MIDI guitar was used to set the number of beats, e.g., so that a louder dynamic translated into longer phrases (see line 4 in the example), and sometimes this was set to a fixed value (line 19). The pattern usually included fixed or randomized tranpositions for each note event (see lines 8 and 23), and the manual to be played on the organ, effectively set with the MIDI channel (lines 7 and 22), but also the settings for note length using the legato parameter.
At the concert the guitarist Stefan Östersjö, performed using this system alongside Federico Visi on electronics, both present on-site next to the Acusticum hyperorgan. Later, Robert Ek added an additional part to the final piece, using his sensor-fitted clarinet (Ek, 2024) to control this algorithm.
Patch 2: TCP/IP – Sestina
This project was part of a three-year research project called Music of the Indeterminate Place, funded by the Swedish Research Council. It involves a recomposed version of Monteverdi's Sestina for hyperorgan, vocal ensemble, dancer, guitars, clarinet, and electronics, premiered at Studio Acusticum in Piteå, Sweden, October 1, 2023. Here, the TCP/IP quartet collaborated with the renowned Erik Westberg Vocal Ensemble, and the dancer and choreographer Åsa Unander-Scharin. In this production, the Acusticum organ was used. Within this project, I developed an algorithmic system that enables live interactions with a hyperorgan. With this algorithmic hyperorgan control, a musician equipped with an instrument that can output control data can use their respective instruments to perform an improvised reading of the original score, resulting in a real-time re-composition of the Sestina. The hyperorgan plays the resulting polyphonic structures all drawn from the original score, filtered by the algorithm. Thus, Monteverdi's composition is repurposed and reconceptualized for use as a dynamic interface by the members of the TCP/IP Quartet in order to explore and create novel interactions between remote instruments and musicians.
Algorithmic Organ Control
Using standard MIDI files of the original score of Sestina as a starting point, I wrote a SuperCollider class that converted MIDI note messages to events, as illustrated above. This step was taken to add the flexibility of SuperCollider's pattern library in order to enable a more direct interaction with musical parameters. For example, new patterns could be chained into the patterns generated by the Monteverdi score, thus allowing altering of parameters, e.g., transposing or replacing note events by means of another algorithmic process. Further, it opens up for the addition of external controllers and live coded interactions to be added and mixed into the process, before converted back into MIDI note events to send to the organ. This allows for an on-the-fly re-composition, but also an understanding of the piece as a dynamic system that could be subject for recontextualization.
After conversion, the resulting patterns can be triggered to play for a certain duration, e.g., 4 beats, and then pauses. The next trigger resumes playing from that point in time, pausing after the specified number of beats. This enables a gradual traversal through the piece, exploring the affordances of the algorithm along the way, but also for the modularization of control because the parameter space can be shared among several performers.
Setup
For live performance, a Roland GR-55 MIDI guitar was used, set up so that each of the 6 strings sends midi note messages on separate channels. Each note-on message from the guitar triggers a corresponding copy of the selected pattern to move forward the specified number of beats, thus traversing through six parallel, unsynchronized layers of the same musical structure.
After deciding on the content and order of the sections, a simple graphical interface (shown below) was used in order to select between them during performance. A switch pedal could also be used to step forward in the list of sections. The GUI also includes a button for turning the hyperorgan MIDI control on and off. This was implemented to enable guitar playing without triggering the organ (this was also helpful to avoid unwanted note triggers when not playing since the guitar interface was rather sensitive). Further, the continuous pedal of the GR-55 was used to control the density of note events (i.e. the probalility for notes vs. rests).
In the piece, selected movements of the Monteverdi served as material for instrumental interludes with the quartet. In these interludes, typically the entire movements was read from beginning to end, although in an entirely new counterpoint. During the process of working out the organ interaction, we collaboratively chose different sections of the score, based on harmonic material and the musical effect we wanted to achieve. The three videos below are Interludes 1-3 from the first live performance of the Sestina, made at Studio Acusticum, October 1, 2023.