The Logic Off Topic list

> You are in C major, (OK) and at the end of some passage you 
> have an E chord
> (OK) in
> 
> > order that you can continue in A ­ so you have moved from C 
> to A, and used
> E
> 
> > as your modulating chord
> 
> 
> 
> I am more confused now sorry David, but can you try and 
> explain with more
> examples  please.

Hi Debbie, I will try to explain. If the terms
confuse you even more, then you need to brush
up on basic diatonic music theory, such as:

-diatonic chords (chords built on each note of the key)
-cycle of 5ths
-tritone substitution (replace a chord with a chord a flat 5th away)
-standard chord progressions like two-five-one (ii-V7-I), minor
two-five-one, etc.
-secondary dominant chords.

(gross simplifications etc follow)

The modulating (pivot?) chord is a chord that has
a function in both keys. With regards to the
previous example, we are talking C major and A minor
I assume. That means that Emin7 (E G B D) is the chord 
built on the third scale degree of C major (since E
is a third up from C). It also happens to be the chord 
built on the 5th scale degree of A, since E is a fifth
up from A. So, if you start out in C major, then whenever
you hit an Emin7 chord, you could follow that with an
Amin7 chord, which would give you a weak but workable
cadence in A minor, and you could then proceed in A minor.

So this give us:
	Cmaj7           Emin7           Amin7

This example would be stronger if you had:
	Cmaj7           Bmin7b5  Emin7  Amin7

since the Bmin7b5  Emin7 functions as a two-five
progression in A minor, as well as being the seven
and three chords in C major.
Even better would be:
	Cmaj7           Bmin7b5  E7b9  Amin7

which provides a very strong cue that we are moving
to A minor through the ii7b5 V7b9 
(two-minor-seven-flat-five, five-seven-flat-nine) 
progression. For further reference, an E7 
is the V7 in A minor, and is the secondary 
dominant of the six chord in C major.

So a way to use this is to set up the first key
with a few bars (4 or 8 at least) and then move
to the second key with a couple of chords that
have a meaning in both keys, so although you
move to another key, you have a smooth progression
through the key change... To hear the effect,
play a few bars of Cmaj7, then play the above
examples and listen, you should hear the key
change in each case.

Hope this makes sense. There is a LOT more to learn
on this subject, but maybe this can get you started.

I am using terminology from jazz theory, but it's
not too different in classical music.

	-smeet