An interval is the difference in pitch between two sounds. In music, intervals can be linear, such as the successive notes in a scale or a melody; or vertical, when the notes are sung or played at the same time, as with a harmony or chord.
In this corner of the lab, I’ll be exploring the vertical use of intervals, looking at all sorts of scales to see what inspiration these can provide when you’re looking to create new music.
In case you’re unfamiliar with how notes are named
C4 (or middle C) sits in the middle of a full-size piano keyboard. It has a pitch of 261.6 Hz. If you halve the frequency you get C3, then halve again you get C2 and so on down to a very deep C1. If you double the frequency of middle C you get C5 and if you keep doubling you get to a piercingly high C8. The gap between any of these C notes and the next one up or down is called an octave.
In Western music, there are twelve notes between any C note and the next C up or down (the same 12 notes apply just as well if you start on any note other than C):
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| C | C#/Db | D | D#/Eb | E | F | F#/Gb | G | G#/Ab | A | A#/Bb | B |
The interval between any of these 12 notes is called a semitone (or a half step). To move up or down by a semitone on a keyboard, simply move to the adjacent key (black or white). On a guitar, move up or down by one fret.
Twelve is a lovely number because it can be divided by 1, 2, 3, 4, 6 and 12, and that allows for some interesting experimentation as we shall see.