This is a demo of the H-Pi Tonal Plexus TPX6s, a keyboard designed for creating microtonal music.

“Here is a sketch using 2 main ideas. The first is a motive including the 11th and 13th harmonics, and the second is a sequence using natural 7ths. Sorry, the camera angle is not the greatest as it hides what my right hand is doing. The sound is 019 ChrchOrgn from the internal synth, with reverb setting on 07 (delay), all max values.”

For a lot of people – H-PI’s keyboard will look like a bizarre monstrosity. But for musicians interested in exploring alternate tunings, it’s one of the most advanced keyboards ever created.

TPX6s: Six Octaves 1266 Keys Microtonal MIDI Keyboard Controller with General MIDI Synthesizer and Stereo Amplifier

• tuning
  • default JND master tuning = 205ET
  • 32 full range programmable tunings with Tonal Plexus Editor software
  • general MIDI compatibility — Compatibility Charts
  • selectable MIDI pitch bend resolution: std = 1.56 cents (7-bit), high = 0.01 cents (14-bit)
• top panel
  • four faders: control channel panning, channel modulation, channel volume and key velocity
  • jog dial: select and enter preset program parameters
  • 4 x 20 LCD character display: active channel polyphony, currently selected preset, tuning, bank, patch, faders / pedals status
  • sixteen channel switches with LED indicators: selectable MIDI output channel polyphony, from 1 to 16 voices
  • sixteen patch buttons: store and recall synthesizer banks and patches
  • sixteen tuning table buttons: store and recall tuning tables
  • switches for sustain pedal polarity, pedal input direction, MIDI pitch bend resolution and local control on/off
• back panel
  • power: 12V DC international transformer input
  • MIDI IN / program: connect to computer or external controller (used with local control off for external control or to upload tunings)
  • MIDI OUT (tuned): connect to any general MIDI tone module or sampler for tuned output
  • sends the following MIDI data on selected channels
    • bank select, patch change, pitch bend range RPNs, selectable 7-bit / 14-bit pitch bend
    • note on / note off (one note per channel = monotimbral up to 16 voice polyphony)
    • panning, modulation, MIDI volume and MIDI key velocity (controlled by top-panel faders or external pedals)
  • MIDI THRU (out untuned): connect to computer or external module for untuned output and external control (used with local control off)
  • SUSTAIN: connect a damper pedal to this 1/4” mono jack to control MIDI sustain
  • pedals VELOCITY, VOLUME: connect Lo-Z (25K) mono volume pedals to these 1/4” jacks to control MIDI key velocity and MIDI volume (pedals override top panel faders)
• TPXE Tonal Plexus Editor software
  • cross-platform compatibility (Mac OSX and Windows XP)
  • intuitive user interface
  • tunings formatted as text files
  • import Scala files
  • upload tunings via the keyboard MIDI in port