Brian Baumbusch – Polytempo Music and 3D Sound Choreography
I think of the relationship between the musical form of Polytempo Music and the way in which each instrumental line is programmed to move around the 3D stage as a choreography of sound. This choreography is composed at the same level of granularity and counterpoint as the music itself, though via different means. To design music, I use a combination of notation techniques to organize and decorate sound over time; to create the sound choreography, I use a collection of proprietary scripts and drive them with keyframe animation, a technique that dates back over 100 years. Both practices involve dividing, organizing, and decorating time, and therefore work in tandem in my own practice.
By writing all of the music before beginning the design of the sound choreography, I knew in advance what my intentions were for “staging” the music into a fluid 3D animation, and I had a preliminary concept of how the musical structure and counterpoint might manifest into a sound choreography. Often, the sound choreography is intended to spatialize the music so that as the listener, we can interact with different ways of hearing the music by moving around it intentionally. In this interview, I describe how the sound choreography is sometimes designed to allow the listener to choose which tempo stream they want to hear most prominently by moving to different positions around the stage in order to get closer to the instruments that are playing in those different tempo streams; the relevant portion of the interview starts at 3:05.
Often, the sound choreography was directly inspired by my process of composing the music. On many occasions, my first step in writing sections of music was to hand draw a tempo map to outline a polytempo structure for the 12 instruments.
(Movement 5: “Hex Tree” – tempo map)
In several instances, the visual designs of these tempo maps helped to inspire the ensuing sound choreography. The end of movement 9 provides an example of this.
(Movement 9: “Pas de deux” – closing section tempo map)
The tempo map in the example above shows a musical structure where a collection of instruments begins by playing together in a single tempo, and gradually this single tempo stream unravels into four separate tempo streams that reach a 12/11/10/9 stacked polyrhythmic relationship before braiding themselves back to a single tempo. Here is a screenshot of what the sound choreography looks like as this polytempo structure unfolds:
(Movement 9: “Pas de deux” – closing section 3D sound choreography)
This animation snapshot, which itself provides a sort of visual score of what’s happening sonically because the trails we are seeing present 3D waveforms undergoing turbulence over
time, shows how all of the instruments were moving together in a single stream while playing at the same tempo during the oldest portion of the visible trail (arching around the top perimeter of this image); as the tempos splinter, so do the positions of the sound sources with respect to one another, until they rejoin at the same position as their tempos fuse. Acoustically, this sound choreography presents the ensemble sound in “mono” when the instruments are playing in the same tempo, and splits the sound into an 8-object spatial audio entity as the tempos split apart.
Working in this capacity, my goal was to create deep fusion between the musical structure and the sound choreography throughout the full 48-minute experience of Polytempo Music
I currently hold a provisional patent for this method of animation, which is defined in the patent as “spatial audio animation.”