Reference · module 4
Intervals
Everything this module explains, on one page.
Naming intervals
Name the distance between two notes by counting.
- An interval is the distance between two notes. It is named by counting letters, both ends included: C up to E counts C, D, E — three letters, so it is a third.
- Neighbouring letters make a second, like C–D. Skipping one letter makes a third, like C–E. On the staff a third goes line to line or space to space.
- C up to G counts five letters: a fifth, the open, steady sound many tunes begin with. C to the next C counts eight: an octave.
The mistake you are about to make
C–E = a second
C–E = a third
C to E is two steps, so it feels like a second. Intervals count letters with both ends included: C, D, E is three.
Major, minor and perfect
Tell a major third from a minor one by counting semitones.
- Two thirds can differ in size. A major third spans 4 semitones, like C–E, and sounds bright. A minor third spans 3, like A–C, and sounds darker.
- Letters alone do not tell the size: C–E and D–F are both thirds, but C–E is 4 semitones and D–F only 3. Count the keys to be sure.
- A perfect fifth spans 7 semitones, like C–G. After the octave, which is 12 semitones, it is the steadiest interval there is, and tuners rely on both.
The mistake you are about to make
D–F = a major third
D–F = a minor third
D–F looks like C–E moved up one letter, so it seems the same interval. It crosses the E–F semitone and is one semitone smaller.
Hearing intervals
Recognise an octave, a fifth and a third by ear.
- Ear training starts with a few very different intervals. An octave sounds like the same note, only higher. A fifth sounds hollow and open. A major third sounds sweet and full.
- You already know these sounds from songs: many melodies open with a leap of a fifth or an octave. The lesson only gives them names you can think with.
- Listen more than once, and sing the two notes back if you can. Speed is not the goal: after a week of short sessions the three start to sound plainly different.