Before even tempering, various different tuning schemes were used. The Harmonic Classic scale was built on perfect fifths and looked like this:
| Interval | Note | Ratio |
| 0 | C | 1:1 |
| 1 | C# | 16:15 |
| 2 | D | 9:8 |
| 3 | D# | 6:5 |
| 4 | E | 5:4 |
| 5 | F | 4:3 |
| 6 | F# | 7:5 |
| 7 | G | 3:2 |
| 8 | G# | 8:5 |
| 9 | A | 5:3 |
| 10 | A# | 7:4 |
| 11 | B | 15:8 |