The Architecture of Music

The Circle of Fifths

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Harmonic Intervals

Whether notes are played individually in a progression or in unison as in a chord, there are two ways to describe the way a combination of notes will sound, using intervals and harmonic intervals. Intervals are the sequential semitone distance between notes. However, this is not a good way to describe the way two notes will sound together because two notes one interval apart played in unison (min2), sounds in resonance. It is arguably one of the most dissonant sounds a combination of two notes can make, or the sound heard when two notes are slightly out of tune.

Harmonic intervals use perfect 5th intervals equal to seven semitones to describe the underlying harmonic relationship of two or more notes. They describe the sound created between notes better than semitone intervals because two notes played one harmonic interval apart sounds in repose. Study the diagram below to understand the difference between intervals and harmonic intervals. The harmonics give us a way to analyze sound using a phenomenon of nature that describes the way two or more notes sound together. By placing all the harmonic intervals next to each other, we can now see the perfect 5th interval relationships of all the notes.

Intervals and Harmonic Intervals Diagram