Delta-rational chord: Difference between revisions
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A delta-rational chord is determined by two things: | A delta-rational chord is determined by two things: | ||
* the dyad formed by its lowermost two notes; | * the dyad formed by its lowermost two notes; | ||
* its ''delta signature'' which has integer ratios, i.e. a list of (scaled) frequency increases between successive notes, their ratios showing the simple rational relationships, with a + before each increase. Note that whether the deltas are rationally related ''to each other'' | * its ''delta signature'' which has integer ratios, i.e. a list of (scaled) frequency increases between successive notes, their ratios showing the simple rational relationships, with a + before each increase. Note that whether the deltas are rationally related ''to each other'' determines whether a chord has the DR property, not whether the deltas are related to the frequency of the root. | ||
For example, a chord with a +1+2+1 delta signature is ''a'':(''a''+1):(''a''+3):(''a''+4) for some possibly irrational ''a''. | For example, a chord with a +1+2+1 delta signature is ''a'':(''a''+1):(''a''+3):(''a''+4) for some possibly irrational ''a''. | ||