Conjuring the Machine (2014) conceives of TAPI (Transportable Automatic Percussion Instrument) as a “magical object” whose powers are unlocked through a ritualistic performance on electric guitar. The piece consists of noisy, processed guitar mixed with slow, regular rhythms leading to faster passages of complex polyrhythm. Impulse and amplitude tracking of Ebow and plucked guitar textures generate an additional percussive layer that that intertwines with slow, spacious rhythms and faster, complex syncopation.
Conjuring the Machine features a granular MIDI note generation technique that allows high-level control of onset time and amplitude (velocity) of sonic grains produced by short, rapid attacks on TAPI. This granular technique is used in two ways: First, the amplitude of Ebowed guitar is used to control the amplitude of all grains, directly controlling the volume envelope. Second, note lengths of picked notes on the guitar are mapped to envelope durations, allowing the granular texture to follow the performed guitar rhythms.
TAPI is a travel-ready, robotic percussion battery consisting of two woodblocks, two cowbells, and a chime built into a vintage 1970s briefcase. The instruments are equipped with contact mics that allow direct amplification and processing of the acoustic sound. TAPI was built in 2012 by Expressive Machines Musical Instruments.