The ideal embodiment of the bilinear chromatic keyboard embraces a third independent row of raised keys corresponding to the same notes as the lowest manual, enabling the performer to reach them from the second (middle) row more easily, facilitating the playing of chords and scales[8]. This third row of keys is at a similar height as the second row but placed further back.
A
one-octave section of this keyboard is shown below:
With this design, both positions are available as the note C is both on the bottom row and on the raised row.
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[8] This third row of notes could also be programmed to play quarter-tones between a chromatic first and second row of keys; in fact, since a computer can make all keys fully tuneable, it would be possible to produce any desired scheme of notes across the keyboard.
[9] With any of these designs, all keys corresponding to C and F (in the default position) should have a different surface texture to the other keys, so that one note on the lower row and one note on the higher row is identifiable by touch alone.
[11] In addition to the simple two-position switch or mechanism to alter the pitch by one semitone, it would be useful to add a separate transposing switch or mechanism to transpose the notes of all keys by any desired interval, thus enabling the ‘white keys’ to play the notes of any major scale. Again, this might be useful for musicians who wish to play the instrument in relative positions rather than by their fixed pitch, but with the added benefit of having the white keys as a guide to the chosen key.
[12] The arrangement here shows the default position of this xylophone instrument. However, the musician may prefer the transposed position, in which case, the top row of bars can be moved to the bottom row.