Section 33.7 Transposition (T\(\text{}_{n}\))
Transposition is an operation performed as T\(\text{}_{n}\), where n is the number of semitones up a set is transposed. For example, [1, 2, 4, 6] at T\(\text{}_{4}\) 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 T\(\text{}_{9}\) 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 T\(\text{}_{9}\): | + | 9 | 9 | 9 | 9 |
| Result: | 15 | 17 | 19 | 20 | |
| Make numbers modulo 12: | – | 12 | 12 | 12 | 12 |
| Result: | 3 | 5 | 7 | 8 |
