The secondary dominant (V7) that tonicizes a chord.
secondaryDominant names its target by scale degree, so it only
reaches the degrees a key actually has. This takes the target chord itself
and needs no key at all, which is what lets a borrowed or chromatic target —
bVI of a major key, a Neapolitan, any chord a modulation left behind — have
its dominant built without first inventing a degree for it.
A rootSpelling hint on the target moves with the root, so a flat-named
target yields a flat-named dominant (Eb gives Bb7, not A#7).
A dominant-seventh chord a perfect fifth above the target's root.
Throws
If the target's root pitch class is not a finite number.
Example
import { makeChord, secondaryDominantOf } from'@libraz/libcantus'; secondaryDominantOf(makeChord(8, 'maj')).rootPc; // 3 — Eb7 tonicizes the // borrowed bVI of C major
The secondary dominant (V7) that tonicizes a chord.
secondaryDominant names its target by scale degree, so it only reaches the degrees a key actually has. This takes the target chord itself and needs no key at all, which is what lets a borrowed or chromatic target — bVI of a major key, a Neapolitan, any chord a modulation left behind — have its dominant built without first inventing a degree for it.
A
rootSpellinghint on the target moves with the root, so a flat-named target yields a flat-named dominant (Eb gives Bb7, not A#7).