Pitch Relationships
Senior 1 · Music
Pitch Relationships
Lesson 4 of 5
25 min
When a choir sings in harmony, the altos and the sopranos sing different notes at the same time, and the distance between those notes decides whether the sound is sweet, bright or tense. When you sing a melody, you leap from note to note by different distances. The distance between two notes is called an interval, and naming intervals exactly is one of the most useful skills in music.
An interval is the distance in pitch between two notes. If the notes are sounded one after the other, it is a melodic interval. If they are sounded together, it is a harmonic interval.
Every interval has a two-part name: a number (such as 3rd or 5th) and a quality (such as major or perfect). Always find the number first.
Count the letter names from the lower note to the upper note, including both. C to E covers C, D, E: three letters, so it is a 3rd. C to G covers C D E F G: a 5th. Two notes on the same pitch make a unison, and eight letters (C up to the next C) make an octave. Intervals up to an octave are called simple intervals.
On the staff there is a quick check: 3rds, 5ths and 7ths go line to line or space to space; 2nds, 4ths, 6ths and octaves go from a line to a space or from a space to a line. Accidentals never change the number, because they do not change the letter: C to E♭ is still a 3rd.
Two 3rds can be different sizes, so the number alone is not enough. To find the quality, count the semitones between the notes on the keyboard and compare with this table:
| Semitones | Interval | Short |
|---|---|---|
| 0 | perfect unison | P1 |
| 1 | minor 2nd | m2 |
| 2 | major 2nd | M2 |
| 3 | minor 3rd | m3 |
| 4 | major 3rd | M3 |
| 5 | perfect 4th | P4 |
| 6 | augmented 4th or diminished 5th | A4 or d5 |
| 7 | perfect 5th | P5 |
| 8 | minor 6th | m6 |
| 9 | major 6th | M6 |
| 10 | minor 7th | m7 |
| 11 | major 7th | M7 |
| 12 | perfect octave | P8 |
A handy set to learn by heart: measured up from doh (C), every note of the doh scale makes a major or a perfect interval.
Sing each one on sol-fa, d–m, d–s, d–d', and you will start to recognise their sounds: the major 3rd is bright, the perfect 5th is open and hollow, and the octave sounds like the same note higher.
E to G. Letters E F G: a 3rd. Semitones: E–F (1), F–F♯ (2), F♯–G (3). Three semitones is a minor 3rd, one semitone smaller than the major 3rd C–E, even though both look the same on the staff.
D to A. Letters D E F G A: a 5th. Semitones: 7, so it is a perfect 5th.
F to B. Letters F G A B: a 4th. Semitones: 6, one more than a perfect 4th (5), so it is an augmented 4th. This is the only 4th between white keys that is not perfect.
C to E♭. Letters C D E: a 3rd (the flat does not change the letter). Semitones: 3, so it is a minor 3rd.
Tip
Letters for the number, semitones for the quality. Count letter names, including both notes, to get the number. Then count keys on the keyboard to get the quality. Perfect: 4th = 5 semitones, 5th = 7. Major 3rd = 4, minor 3rd = 3.
Try each question first, then check the worked solution underneath.
What is the number of the interval from G up to D?
Solution: A 5th: G A B C D is five letters.
Name the interval from A up to C.
Solution: Minor 3rd. Letters A B C give a 3rd; semitones A–A♯, A♯–B, B–C give 3.
Name the interval from D up to F♯.
Solution: Major 3rd. Letters D E F give a 3rd; semitones D♯, E, F, F♯ give 4.
Name the interval from E up to B.
Solution: Perfect 5th. Letters E F G A B give a 5th; there are 7 semitones.
Name the interval from B up to F.
Solution: Diminished 5th. Letters B C D E F give a 5th, but there are only 6 semitones, one fewer than a perfect 5th.
Remember
Sources and credits
The lesson text, the notation and keyboard diagrams, the worked examples and the practice were written by Ganzaa.
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
