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5.2.5 Diatonic vs Chromatic: Semitones In an Octave
There are 12 semitones in an octave. But in theory, how many different scales could there be, diatonic vs chromatic?
More than you’ll find on the skin of your average catfish.
Why so many?
Because scales are combinatorial. You start with a finite number of items (all the notes of a chromatic scale), plus some rules about picking and combining the items (the notes you choose from the chromatic scale to make up your own scale). The more notes in your original chromatic scale, the more “sub-scales” you can create.
Here are some scale construction “rules”:
- Start with an equal-interval chromatic scale. It can have any number of notes, up to a maximum of, say, 30 in the octave. (The more notes to the octave, the harder it is for your brain to distinguish adjacent notes.) In the diatonic system, there are only 13 notes in the chromatic octave, including the first and last notes. But other musical systems divide the octave into more than 13 notes. In theory, you could start with a chromatic scale of, say, 30 notes to the octave, instead of 13.