Musical interval stimuli used to evoke brainstem responses
| Interval | Musical pitches | No. of semitones | Ratio of fundamentals | Frequency components (Hz) |
|---|---|---|---|---|
| Unison (Un) | A3, A3 | 0 | 1:1 | Note 1: 220, 440, 660, 880, 1100, 1320 |
| Note 2: 220, 440, 660, 880, 1100, 1320 | ||||
| Minor 2nd (m2) | A3, B♭3 | 1 | 16:15 | 220, 440, 660, 880, 1100, 1320 |
| 235, 470, 705, 940, 1175, 1410 | ||||
| Major 3rd (M3) | A3, C#4 | 4 | 5:4 | 220, 440, 660, 880, 1100, 1320 |
| 275, 550, 825, 1100, 1375, 1650 | ||||
| Perfect 4th (P4) | A3, D4 | 5 | 4:3 | 220, 440, 660, 880, 1100, 1320 |
| 293, 586, 879, 1172, 1465, 1758 | ||||
| Tritone (TT) | A3, D#4 | 6 | 45:32 | 220, 440, 660, 880, 1100, 1320 |
| 309, 618, 927, 1236, 1545, 1854 | ||||
| Perfect 5th (P5) | A3, E4 | 7 | 3:2 | 220, 440, 660, 880, 1100, 1320 |
| 330, 660, 990, 1320, 1650, 1980 | ||||
| Major 6th (M6) | A3, F#4 | 9 | 5:3 | 220, 440, 660, 880, 1100, 1320 |
| 367, 734, 1101, 1468, 1835, 2202 | ||||
| Major 7th (M7) | A3, G#4 | 11 | 15:8 | 220, 440, 660, 880, 1100, 1320 |
| 413, 826, 1239, 1652, 2065, 2478 | ||||
| Octave (Oct) | A3, A4 | 12 | 2:1 | 220, 440, 660, 880, 1100, 1320 |
| 440, 880, 1320, 1760, 2200, 2640 |
Italic values represent frequency components shared between both notes in a given dyad. Bold intervals are consonant; lightface intervals, dissonant. Harmonics of individual notes were calculated based on the ratio of their fundamental frequencies (i.e., just intonation).