Stop 2 of 6
Intervals by ear
Consonance, dissonance, inversion and compound intervals.
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Stop 2 of 6
Consonance, dissonance, inversion and compound intervals.
Knowing an interval’s name is useful; recognising it when you hear it changes the way you play. It lets you work out a melody without tab, know instantly whether a chord is major or minor, and imagine a phrase before you play it. At this stop you train your ear with a method: you learn to feel each interval’s tension, to turn it upside down and to build your own reference points.
Put on headphones and listen to these three groups of harmonic intervals, all from A. Don’t think about names: just notice whether the two notes blend or rub.
Group 1
Group 2
Group 3
Group 1 sounds hollow and stable; group 2 sweet and full; group 3 rubs, as if it wanted to move. That is versus :
| Type | Intervals | Feeling |
|---|---|---|
| Perfect consonance | P1, P8, P5 (and P4) | stable, hollow, “colourless” |
| Imperfect consonance | M3, m3, M6, m6 | stable, sweet, major or minor colour |
| Dissonance | M2, m2, M7, m7, tritone | tension, friction, urge to move |
The fourth is a curious case. On its own it sounds as open as the fifth. But in classical harmony, when the fourth sits between the bass and an upper voice, it is treated as a dissonance because it wants to resolve (think of a suspended chord returning to its third). That is why the fourth appears in brackets in the tables: consonant to the ear, slightly unstable over the bass.
Play C with E above it: a major third. Now move the C up an octave, above the E. The two notes are the same, but the interval is now E–C: a minor sixth. You have just made an .
Three rules, always the same:
| Interval | Inversion |
|---|---|
| M2 (2) | m7 (10) |
| m3 (3) | M6 (9) |
| M3 (4) | m6 (8) |
| P4 (5) | P5 (7) |
| A4 (6) | d5 (6) |
Look at the last row: the inverted is still a tritone. It is the only interval that is its own mirror image.
Inversion doubles your vocabulary without learning anything new. Sixths are inverted thirds, and on strings 3 and 1 they make a beautiful sound for decorating melodies. Here are sixths through the C major scale (mute string 2 with the pad of the finger fretting string 3):
When an interval is larger than an octave it is called a . To name it, subtract 7 from the number and keep the quality: a major ninth is “an octave plus a major second”.
| Compound | Equals | Half steps | From C |
|---|---|---|---|
| Ninth (M9) | 8ve + M2 | 14 | D |
| Tenth (M10) | 8ve + M3 | 16 | E |
| Eleventh (P11) | 8ve + P4 | 17 | F |
| Thirteenth (M13) | 8ve + M6 | 21 | A |
Hear the difference between a second and a ninth. The letters are the same, but the ninth “breathes” much more: the distance softens the friction.
On guitar, compound intervals appear naturally: you play a bass note on a low string and a high note several strings above.
String 5, Fret 3: C3 · 1 · Scale tone
That is why jazz and modern pop chords are called Cadd9 or C13: the numbers 9, 11 and 13 are these compound intervals above the root. You will meet them in depth later on the journey.
The classic method for recognising intervals is to link each one to the opening of a well-known song. It works, but it depends on songs you may not know. Here you will use something sturdier: the major scale you already carry inside. If you hear the lower note as “Do”, the upper one lands on some degree of the scale.
Listen to each motif and sing it. They are all built by you, for you: they come from no song.
| Interval | Your reference | Listen |
|---|---|---|
| m2 | the last step of the scale, B → C: “arriving home” | |
| M2 | the first step of the scale, C → D | |
| m3 | the start of a minor arpeggio | |
| M3 | the start of a major arpeggio | |
| P4 | a call: from the fifth below up to the tonic | |
| Tritone | a rub that resolves up by a half step | |
| P5 | the power chord, note by note | |
| m6 | a major third “upside down” | |
| M6 | from the tonic to the sixth degree | |
| m7 | the blues seventh, falling to the sixth | |
| M7 | almost the octave: one half step short | |
| P8 | the same note, higher |
The same interval sounds different depending on direction. A fifth going up sounds like a call; the same fifth going down sounds like a close.
For descending intervals, take the upper note as your reference and sing the scale downwards. Another trick: a descending fourth (C → G) is the inversion of an ascending fifth, so it lands on the same note under a different name.
For harmonic intervals (together), start with the sorting from the first scene: does it blend, sweeten or rub? That narrows the options to three or four. Then sing the lower and upper notes separately and apply your melodic reference.
Goal: Play and sing all 12 intervals over A, and tell by ear whether each is a perfect consonance, imperfect consonance or dissonance.
With a partner, or with the ear-training tool: one plays two notes without looking, the other answers with number and quality. Start with just P4, P5, M3 and m3; when you get 8 out of 10, add M2, M6 and m7, and finally the rest.
Goal: Get 8 out of 10 randomly played intervals right, first melodic, then harmonic.
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