The twelve acoustically correct diatonic-scale intervals do not make exact octaves, missing by one quartertone {Pythagorean comma}. To fit intervals into octaves, different keys {mode, Greek music} use different interval series, with different spacing between tones and semitones, so keys sound different.
Arts>Music>Theory>Scale>Scales>Diatonic
2-Music-Theory-Scale-Scales-Diatonic
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Date Modified: 2022.0224