Delta-rational chord: Difference between revisions
| Line 13: | Line 13: | ||
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 it is whether the deltas are rationally related ''to each other'' that defines DR, 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''. | ||