Now let's see if we can reason out the ambiguity of the vii7 chord and be able to use it and make it do what we want it to do. That puts us in command of the situation.Facts:
(1) Each vii7 chord is constructed on the vii scale degree of some minor scale in the harmonic minor mode.
(2)Each tone of the vii7 chord can be written differently (enharmonic differences).
(3)These vii7 chords all sound the same. G#dim7, Bdim7, Ddim7, E#dim7.
(4)G#dim7 and Abdim7, AND E#dim7 and Fdim7 are the enharmonic equlivalents of each other and also use the same exact sound for their root.
If all the above are TRUE then the vii7 chord could be used for modulation to another key. Play the following examples and test this out.
MODULATION USING THE vii7 chord as the pivot chord.
Changing into key of Am and Cm.
