Prelude and Fugue in 8ET

Written in 2007. (An organ with a more powerful pedal division would be better for this, but this is all I have.)

Text below excerpted from the Appendix of "The Equal Tempered Keyboard": a collection of 31 contrapuntal keyboard works written in every equal division of the octave between 5 and 20.

"There are no Major 3rds or Perfect 5ths in 8ET; music written in this tuning must rely heavily on the minor 3rd, which is tuned the same as it is in 12ET, since both tunings are divisible by 4. Where 12ET contains three diminished 7th chords (4 x 3 = 12), 8ET contains only two (4 x 2 = 8). The structure of 8ET is reminiscent of a diminished scale (a.k.a. octatonic scale) in 12ET, but whereas an octatonic scale alternates whole and half steps, in 8ET there is only one scale step: the Wide minor / Narrow Major 2nd, a halftone plus a quartertone spanning 150¢. This 2nd is both too narrow to be a proper Major 2nd, and too wide to be a proper minor 2nd, so it serves both functions in an ambiguous manner depending on context; therefore, I call 8ET the ambiguous diminished scale, or ambidiminished scale. Harmony in 8ET is relegated to minor and diminished sounds, but it is much more flexible than an octatonic scale because of its ambisecond.
...
An octatonic scale contains Perfect 4ths and 5ths, but there are no Perfect 4ths or 5ths in 8ET. The only 4th is a Narrow 4th, enharmonic with a Wide Major 3rd. By inversion, the only 5th is a Wide 5th, enharmonic with a Small minor 6th. These quartertone intervals sound generally unconvincing, and are best avoided unless their function is made overwhelmingly clear by context. Harmonic motion in 8ET is best limited to its two circles of thirds. The most convincing melodic leaps are the intervals it shares with 12ET: the minor 3rd, tritone, and octave.
...
Without the possibility for Major sounds, the overall mood of 8ET is dark and severe. For music in that range of expression, it is a strikingly effective tuning."