Bagua

Bagua is a custom-built MIDI interface designed to spatialize instrument groups using Ableton Live and Xp4l. Drawing inspiration from the bagua (Chinese: 八卦; pinyin: bāguà), a Taoist cosmological system of eight trigrams representing the interplay of opposing forces, the interface reflects both philosophical and spatial approaches to musical design.

The idea emerged from a desire to challenge the linear structure of traditional music controllers (e.g., keyboards) andinstead, adopt a circular layout rooted in symbolic and spatial logics. Owing to our Chinese heritage, we encountered bagua symbols during childhood and were drawn to their spatial metaphors and visual structure, seeing them as a meaningful foundation for organizing sound in a performance space.

The Bagua interface functions as a 12-pad MIDI controller, allowing performers to spatially trigger or modulate audio elements in real time. Each pad can be assigned to different instruments or spatial effects within the DAW, enabling intuitive and symbolic control of the sonic environment.

Technical Components

Bare Conductive Touch Board: Used for touch-sensitive MIDI output. Its accessibility and comprehensive documentation make it ideal for prototyping.

Copper Tape: Conductive surface material used to create touch zones.

Acrylic Panel: Transparent build surface for the final design, combining visual clarity with durability.

Xp4l spatialization software.

Prototyping Process

From early low-fidelity builds to the refined final interface, the development emphasized tactile feedback, visual coherence, and symbolic spatiality. Here, we sketch different layout variations.

First Prototype

The first prototype was constructed with cardboard, copper tape, and a Bare Conductive Touch Board. It is connected with alligator clips to map sensor inputs and paired with a MIDI Fighter Twister to prototype assignments in Ableton Live.

Second Prototype

The first prototype was upgraded to a stretched black canvas on a wooden frame.

A projected image of the Bagua was traced onto the canvas to prototype the layout quickly.

Copper tape was applied to the front in the chosen trigram pattern, with wiring routed behind the canvas to the Touch Board. We drew the bagua from a projected image on a black canvas with pencil, a quick way to make a prototype.

Final Design: The Bagua

The interface was rebuilt on a translucent acrylic plate, elevating the durability and aesthetics of the build. The copper tape design remained on the surface, with internal wiring neatly arranged and visible beneath the plate. The plate is mounted on bolts, elevating it from the base and making the construction both functional and visually expressive, emphasizing the technical and symbolic layers of the interface.

Inspiration

We were inspired to create a circular musical interface, as opposed to the linear design of a keyboard. Having come across the bagua in our childhood through our Chinese roots, we were curious to explore its symbolic relation to space and movement. (source)

The bagua (Chinese: 八卦; pinyin: bāguà; lit. 'eight trigrams') is a set of symbols from China that are intended to illustrate the nature of reality as being composed of mutually opposing forces reinforcing one another. In that way, it seemed like an appropriate starting point for designing a spatial interface.

We were also inspired by Pauline Oliveros’ listening score Wind Horse, particularly its use of circular form and the distribution of sonic elements in space. This helped guide the conceptual placement of instrument groups across the Bagua layout. (source)