User:MusicScienceGuy/Harmonic table note layout

The Harmonic Table note-layout, or tonal array, is a key layout for musical instruments (sonomes) that offers interesting advantages over the traditional keyboard layout.

Its symmetrical, hexagonal pattern of interval sequences places the notes of the major and minor triads together. It is also called the Melodic Table note-layout by its inventor, Peter_Davies, and more rarely the Triad note-layout. It is related to the Wicki-Hayden based keyboards and other Isomorphic keyboards, as explained here.

History
This key layout (2-dimensional tonal array) was initially invented by Peter Davies in 1983 and patented in 1990. The array was renamed the Harmonic Table by the first major manufacturer, C-Thru Music and publicized by the company. This layout is used in the sonome family of keyboards, currently commercially manufactured as the Axis and Opal keyboards.

Special Features of the Harmonic table
There are a large number (~600) of isomorphic note-assignments possible, the Harmonic Table format is unusual in that:
 * Note-values ascend by the musical interval of a perfect fifth along the vertical axis
 * On one diagonal axis notes ascend by a major third
 * On the remaining diagonal axis notes ascend by a minor third
 * The commonly played notes of a chord (except the octave) are clustered close together
 * In fact, any major triad and minor triad, in root position, can be played with a single finger
 * A 7 by 7 array of notes, or Penrose tile is generated by the note-assignment rules

Uses
Of the large number of isomorphic note-assignments possible, the harmonic table format is exceptionally compact: all notes of the major and minor scales fall under the fingers, and all common chords can be played with one or two fingers. All chords found in conventional chord progressions (I, ii, iii, IV, V, vi and viii, as well as others), in some inversions, can be easily played with simple, short hand movements. This key layout has attracted the attention of numerous professional musicians, including Brian May and Jordan Rudess who find that it gives them a novel view of music, which is reportedly very useful in composing. It also works well with novel tunings such as the Bohlen–Pierce scale.

It is in use for ongoing research into microtonal scales by music researchers and composers, in particular Carlo Serafini, Elaine Walker and Dr. Richard Boulanger.