3D spatialization of voices, as well as instrument-specific messages for guitar, wind, and drum controllers. Message types The basic synthesis control messages were: Articulation - 'note on/off' in MIDI Pitch (note number and offset in 0.2 cents) Frequency (in Hz) Loudness - 'velocity' in MIDI Amplitude - 'volume' in MIDI Even/Odd Harmonic balance Pitched/Unpitched balance Roughness Attack character Inharmonicity Pan Left/Right, Up/Down, Front/Back Spatialization distance and azimuth/elevation angles Program Change - immediately and future notes Timbre space X/Y/Z Multiple output levels Time tag Modulation rate/depth/wavetype Controller (performance-oriented) messages included: Key Velocity/Number/Pressure Pitch Bend Wheel Mod Wheel 1/2/3 Switch pedal 1 (Sustain)/ 2 (Soft pedal) /3 /4 Continuous pedal 1 (Volume)/2 /3 /4 Pick/bow Velocity/Position/Pressure Fret/fingerboard Position/Pressure Wind flow or pressure (breath controller) Embouchure (bite) Wind controller keypads Lip pressure/frequency Drum head striking point X/Y position and distance/angle from center X/Y/X position in space Velocity in X/Y/Z dimension Acceleration in X/Y/Z dimension Outcome of the project Although ZIPI provided many outstanding new features, they did not line up well with existing MIDI-based implementations. The unusual addressing scheme which required substantial increase in complexity was the main factor in the lack of its adoption. Maintaining 1,016,127 individual synthesis states was far beyond the capabilities of synth hardware of the time, even though ZIPI developers hinted that there would be some practical limits upon the number of simultaneously available programs and notes. In comparison, MIDI defined only 16 channels that accumulated common channel control messages like program change, volume and pitch, and most digital synthesizers of the time could only provide from 12 to 128 simultaneously sounding notes. As no commercial devices were released supporting ZIPI, the sufficiency of MIDI for most applications and the introduction of the "FireWire" (IEEE1394) as the alternative physical layer soon led to the practical demise of the project. ZIPI web site at CNMAT asserts that IEEE1394 "supersedes ZIPI in every respect," mainly because it has simpler interface requirements: it does not require a hub, supports hot plugging (devices may be added or removed more conveniently), and includes an isolated power distribution scheme. The developers continued on to work on Open Sound Control protocol, currently supported in a wide variety of musical instruments, sensors and software. See also Yamaha mLAN External links CNMAT: ZIPI project ZIPI publications in Computer Music Journal Network protocols Electronic musical instruments