Purple Pd Machine

Purple Pd Machine is a wooden box with an array of buttons and knobs wired to an iPhone 6 via a microcontroller (Teensy LC) and a USB hub (for additional connectivity). Software written in Pure data (Pd) runs on the phone via Mobile Music Platform (MobMuPlat). Stereo audio output is available via sockets that repeat the phone socket, multichannel is available via compatible USB interface. 

The instrument is built around a sound file granulator and a sampler/drum synthesizer that can be sequenced via Euclidean rhythm generator, standard sixteen step grid, or triggered live via buttons (with quantised repeat functions). Standard reverb/delay and filtering effects are included, some of these are mapped to the accelerometer. Sine wave generators are also used to create beating effects. When configured for quadraphonic sound the granulator can automate the placement and velocity of individuals grains while the sequencer outputs in a more blunt fashion, offering various speed and direction of rotation parameters (leading to spinning percussive elements, audio samples, and effects). The audio samples chosen very much speak for themselves, beyond the performer’s attempt to manipulate them. The result is a surprisingly well-ordered assemblage that may nevertheless be liable to melt at any moment.

  • All software and audio samples on Github here.
  • The instrument has eight preset states, which change the role of the knobs and buttons; rough overview here. 

Sonic Interiors @ Sound in Space

Sonic Interiors was performed on July 23rd 2018 at Queensland Conservatorium Griffith University as part of ‘Sound in Space’.  Sonic Interiors explores relatively uncharted territories of timbral and rhythmic space. Sounds and textures uncommonly found in conventional music are navigated, but still the work contains traditional elements and musical gestures. The sonic landscape is at times unfamiliar yet strangely reminiscent. 

Both John and Andrew have developed new bespoke instruments for this work. Andrew’s features ring modulation synthesis controlled by multi-dimensional touch gestures. This process provides a rich diversity of sonic potential whilst always maintaining remnants of the physical gestures used in performance. Effects and quadraphonic sound distribution enhance and relocate what is otherwise a simple monophonic sound source. John’s instrument (Purple Pd Machine) features an array of buttons and knobs wired to an iPhone, resulting in a surprisingly well-ordered assemblage that may nevertheless be liable to melt at any moment. Euclidean rhythms and sound-file granulation are at the foreground of the sound world but the audio samples chosen very much speak for themselves, beyond the performer’s attempt to manipulate them. Quadraphonic sound diffusion is automated and responsive to both tactile input and computational parameters.

The work involves performance with live algorithms where performer agency is augmented by agency in the machines, as they exert their influence in somewhat unpredictable ways. Always, the work emerges from the interactions amongst performance and machines, following a tight compositional structure that still allows for moment-to-moment improvisation and surprise. The performance features a sound-responsive live-projection created using Touch Designer.

Live sound and moving image was captured by Kai Mohrholz, additional footage (which more fully captured the Touch Designer projections) provided by Danny Dela-Bosca. Combined and edited by John Ferguson.

Links to online documentation