7th Chords and Modulation

Commencing with a verbal explanation of how seventh chords are audible in nature as components of the Harmonic Series, the introduction of the gesture conveying the inclusion of the sharpened 4^th (Fi) permits modulation via the major of chord II. Modulation on these lines replaces the Tonic with the Dominant (see Video 55 for the use of dominant 7^th chords in achieving this).