33.7: Transposition (Tn)
33.7 Transposition (Tn)
Transposition is an operation performed as Tn, where n is the number of semitones up a set is transposed. For example, [1, 2, 4, 6] at T4 is [5, 6, 8, 10].
When working in a modulo 12 system, remember that numbers larger than 12 have to be reduced to a number smaller than 12 by subtracting 12 from the larger number. For example, 6, 8, 10, 11 at T9 would result in 15, 17, 19, 20, which, after subtracting 12 from each number, results in 3, 5, 7, 8.
| Pitch classes: | 6 | 8 | 10 | 11 | |
| at T9: | + | 9 | 9 | 9 | 9 |
| Result: | 15 | 17 | 19 | 20 | |
| Make numbers modulo 12: | – | 12 | 12 | 12 | 12 |
| Result: | 3 | 5 | 7 | 8 |