Kyle Gann: Triskaidekaphonia

Recording (MIDI realization) here
PDF score here
CAUTION: Score is meaningless as to pitch without retuning, key given at bottom of this page

Triskaidekaphonia is a piece for virtual electronic piano, i.e., electric keyboard that sounds like a piano. Unlike my earlier microtonal works, this one can be performed live by a soloist, without additional electronics. The tuning is superlatively simple: it consists of merely all the ratios formed by the whole numbers from 1 to 13, of which there are 29:

13/12, 13/11, 13/10, 13/9, 13/8, 13/7 (13/6, 13/5, and so on, are merely octaves of those already mentioned)

12/11, 12/7 (12/10 is the same as 6/5, 12/9 = 4/3, and so on)

11/10, 11/9, 11/8, 11/7, 11/6

10/9, 10/7 (10/8 = 5/4, 10/6 = 5/3)

9/8, 9/7, 9/5

8/7, 8/5

7/6, 7/5, 7/4

6/5

5/4, 5/3

4/3

3/2

1/1

The resulting scale (given in Ben Johnston's notation) is as follows:

Pitch:DE13bEv+E^b EE+ELF7+F13v+F+ F^F#+F#L+G13bG
Ratio:1/113/1212/1111/10 10/99/88/77/613/11 6/511/95/49/713/104/3
Cents:0138.6150.6165 182.4203.9231.2266.9289.2 315.6347.4386.3435.1454.2498

G^A7b+G#LA13bA+ A^LBbB13bBBLC7+C+C^C13L
11/87/5 10/713/93/211/78/5 13/85/312/77/49/511/613/7
551.3582.5 617.5636.6702782.5813.7840.5 884.4933.1968.81017.61049.41071.7

(If you don't have enough experience with just intonation to make sense of this chart, try reading the step-by-step Just Intonation Explained section.) In Johnston's notation, + raises a pitch by 81/80, - lowers it by 80/81, # raises it by 25/24, b lowers it by 24/25, 7 lowers it by 35/36, L raises it by 36/35, ^ raises it by 33/32, v lowers it by 32/33, 13 raises it by 65/64, and F-A-C, C-E-G, and G-B-D are all perfectly tuned 4:5:6 major triads.

This is my first piece to go beyond 11-limit tuning to use the 13th harmonic. I figured out that I could make different scales within this network by taking all notes expressible by the form 13/X, or 11/X, or X/7, and the scales with the smallest numbers would be closest to simple tonality, while the larger-numbered scales will have a much more oblique relationship. Thus the scales that run through the piece are:

13/X:1/1 13/1213/1113/1013/913/8 13/7
12/X:1/1 12/116/54/33/212/7
11/X:1/1 11/1011/911/811/711/6
10/X:1/1 10/95/410/75/3
9/X:1/1 9/89/73/29/5
8/X:1/1 8/74/38/5
7/X:1/1 7/67/57/4
X/9:1/1 10/911/94/313/95/3
X/7:1/1 8/79/710/711/712/7 13/7
X/5:1/1 11/106/513/107/58/5 9/5
X/3:1/1 13/127/64/33/25/3 11/6
X/2:1/1 9/85/411/83/213/8 7/4

Of course, the scales with X in the numerator are overtone series', and those with X in the denominator are undertone series'. Since all the pitches have a simple relationship to 1/1 D, a rhythmicized drone on that pitch runs throughout. The piece, then, moves "in and out of focus" depending on which scale is used at a given moment.

The score (available here as a PDF) uses conventional notation that does not indicate pitch, but merely tells the keyboardist which keys to play. The keyboard is tuned thusly:

Key:Pitch:Ratio:Tuning (relative to normal 12tet):
C1D1/1D0 + 0 cents
D1D1/1D1 + 0 cents
E1A+3/2A1 + 2 cents
F1C7+7/4C2 - 31.2 cents
G1D1/1D2 + 0 cents
A1A+3/2A2 + 2 cents
A#1A^L11/7A#2 - 17.5 cents
B1Bb8/5Bb2 + 13.7 cents
C2B13b13/8Bb2 + 40.5 cents
C#2B5/3B2 - 15.6 cents
D2BL12/7B2 + 33.1 cents
D#2C7+7/4C3 - 31.2 cents
E2C+9/5C3 + 17.6 cents
F2C^11/6C3 + 49.4 cents
F#2C13L13/7C#3 - 18.3 cents
G2D1/1D3 + 0 cents
G#2E13b13/12Eb3 + 38.6 cents
A2Ev+12/11E3 - 49.4 cents
A#2E^b11/10E3 - 35 cents
B2E10/9E3 - 17.6 cents
C3E+9/8E3 + 3.9 cents
C#3EL8/7E3 + 31.2 cents
D3F7+7/6F3 - 33.1 cents
D#3F13v+13/11F3 - 10.8 cents
E3F+6/5F3 + 15.6 cents
F3F^11/9F3 + 47.4 cents
F#3F#+5/4F#3 - 13.7 cents
G3F#L+9/7F#3 + 35.1 cents
G#3G13b13/10G3 - 45.8 cents
A3G4/3G3 - 2 cents
A#3G^11/8G#3 - 48.7 cents
B3A7b+7/5Ab3 - 17.5 cents
C4G#L10/7G#3 + 17.5 cents
C#4A13b13/9Ab3 + 36.6 cents
D4A+3/2A3 + 2 cents
D#4A^L11/7Ab3 - 17.5 cents
E4Bb8/5Bb3 + 13.7 cents
F4B13b13/8Bb3 + 40.5 cents
F#4B5/3B3 - 15.6 cents
G4BL12/7B3 + 33.1 cents
G#4C7+7/4C4 - 31.2 cents
A4C+9/5C4 + 17.6 cents
A#4C^11/6C4 + 49.4 cents
B4C13L13/7C#4 - 28.3 cents
C5D1/1D4 + 0 cents
C#5E13b13/12Eb4 + 38.6 cents
D5Ev+12/11E4 - 49.4 cents
D#5E^b11/10E4 - 35 cents
E5E10/9E4 -17.6 cents
F5E+9/8E4 + 3.9 cents
F#5EL8/7E4 + 31.2 cents
G5F7+7/6F4 - 33.1 cents
G#5F13v+13/11F4 - 10/8 cents
A5F+6/5F4 + 15.6 cents
A#5F^11/9F4 + 47.4 cents
B5F#+5/4F#4 - 13.7 cents
C6F#L+9/7F#4 + 35.1 cents

Enough information is given here to facilitate a performance - kindly contact the composer if this is contemplated. The piece is performable on a five-octave keyboard.

Kyle Gann

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