Here's good, real-world example of music theory in action.
I'm playing a lessons and carols ceremony tomorrow morning at a local church, and the idea is that there will be continuous music throughout the service. We're playing some hymns, a few John Rutter arrangements, and the Willocks arrangements of "O Come O Ye Faithful" (the one with the wonderful fully diminished seventh chord in the last verse) and "Hark, the herald angels sing."
The trick to weaving all of this together into one hour of coherent music is in the transitions. The first piece we're doing is in E minor; the second, in B-flat major--two distantly related keys if ever there were. So the director and/or organist is charged with getting us smoothly from one to the other.
This is exactly the sort of thing that we concluded our Harmony III class this semester: writing (and identifying) modulations to distantly related keys. Here's a case where my sophomores could come in and save the day: "I can get you from E minor to B-flat major no problem! I can do that in four chords or less!"
How might we modulate from E minor to B-flat major? There are any number of ways. G, A, C, and D (sort of) are all common tones. We could modulate via a kind of modal borrowing: C major (vi in E minor) is replaced with C minor (ii in B-flat major). G major (III in E minor) could be reinterpreted as a V(7)/ii in B-flat. We could enharmonically respell viio7 in E minor (D#, F#, A, C) as viio7 in B-flat (A, C, Eb, Gb). We could also enharmonically respell the German augmented sixth chord in E minor (C, E, G, A#) as the V7/V in B-flat major (C, E, G, Bb).
The art of the thing is finding a way to blend thematic material from one into thematic material from the other convincingly...
I'm playing a lessons and carols ceremony tomorrow morning at a local church, and the idea is that there will be continuous music throughout the service. We're playing some hymns, a few John Rutter arrangements, and the Willocks arrangements of "O Come O Ye Faithful" (the one with the wonderful fully diminished seventh chord in the last verse) and "Hark, the herald angels sing."
The trick to weaving all of this together into one hour of coherent music is in the transitions. The first piece we're doing is in E minor; the second, in B-flat major--two distantly related keys if ever there were. So the director and/or organist is charged with getting us smoothly from one to the other.
This is exactly the sort of thing that we concluded our Harmony III class this semester: writing (and identifying) modulations to distantly related keys. Here's a case where my sophomores could come in and save the day: "I can get you from E minor to B-flat major no problem! I can do that in four chords or less!"
How might we modulate from E minor to B-flat major? There are any number of ways. G, A, C, and D (sort of) are all common tones. We could modulate via a kind of modal borrowing: C major (vi in E minor) is replaced with C minor (ii in B-flat major). G major (III in E minor) could be reinterpreted as a V(7)/ii in B-flat. We could enharmonically respell viio7 in E minor (D#, F#, A, C) as viio7 in B-flat (A, C, Eb, Gb). We could also enharmonically respell the German augmented sixth chord in E minor (C, E, G, A#) as the V7/V in B-flat major (C, E, G, Bb).
The art of the thing is finding a way to blend thematic material from one into thematic material from the other convincingly...