- Hi and welcome to another of our little
series of videos, this time
on the subject of modulation.
So let's be sure we
know what modulation is.
This is when we change from
one key to another key.
When we got past 1600 and people
started to think much more
in major and minor keys
and started finding their way
and be a bit more adventurous with chords,
at first one of the
things that made the music
a little bit boring
was the fact that it got stuck in one key
and it didn't go anywhere else.
So composers started to realise
that really to keep music interesting,
it's a good idea to move
around the keys a bit.
So what they did was that they looked for
what's called pivot chords
between one key and the next key.
So a pivot chord means
that you're in this key,
say C major,
you want to modulate to G major,
so you think, well,
which chords come in
C major and in G major
and then you say, well, I'll
take one of those chords,
I'll use it as a pivot chord,
so I kind of go into a
chord like this in C major,
which is chord I
and then I say, well, actually
I'll call that chord IV
in G major, which it is,
so that's a pivot chord,
and having used that chord
I than carry on in G major.
So it's a way of kind of
transitioning smoothly
from one key to the next.
And that served us very well
through the Baroque period
and through the Classical period.
By the time we get to the 19th century,
composers are feeling a bit restricted
by just moving to neighbouring keys
and they want to be able to do something
that involves modulation
to more extreme keys.
So some composers say, well,
why do we have to use a pivot chord?
Why can't we just use a pivot note?
And that's what I'm
just going to talk about
here for a few moments.
So let's take this example,
we're in the key of C major,
so this is the chord that
I've just been talking about
and you can see what would
be chord I in C major,
but it's also chord IV in G major,
so I can easily go to
G major from C major.
I could also go to F major
because this, apart from
being chord I in C major,
is also chord V in F major,
so you can see that we
could do something that's
involving a neighbouring key.
Just adding a sharp or adding
a flat from where we are.
But what happens if I want to do
something a bit more radical?
For example, what would
happen if I wanted to go
from C major to A-flat major?
Well, at one level that's going to seem
fairly impossible, trying
to find a pivot chord
that belongs to C major
and to A-flat major.
It's not going to get
us the journey really.
We could start in C major,
then maybe go to F major,
then B-flat major,
then E-flat major,
and then get to A-flat major,
but that's going to
take quite a long time.
What happens if I just want to
go straight to A-flat major?
Well, this is what happened
during the 19th century,
but it's a technique
that we can still use now
very effectively.
Instead of saying let's
take the whole pivot chord,
let's just take one of the notes.
So I've put that little arrow against C,
so what happens if I take the note C
and I say, well, if I want
to go to A-flat major,
the tonic chord of A-flat major
is going to look like this.
So do you see what's happening there?
The pivot note is this C.
So I'm quite happily
playing along in C major.
And then I think, I'd quite
like to go to A-flat major now,
so I use that C and I say, well,
here's a chord of A-flat major,
so do you see how that happens
just by using that note?
I finish in C major then
I go to A-flat major.
And I'm quite happy in A-flat major.
It works quite well, doesn't it?
You don't feel a big bump.
You sometimes feel a slight
lift, slight surprise,
but the pivot note carries
us from one key to another.
It's not the only possibility is it?
I mean, I could decide to
use the E as a pivot note
and then say, well, could
I not finish in C major
and then go to E major.
So I'm finishing in C major.
And then go to E major.
And off I go into that key.
So this is just introducing the notion
that if you want to be a little bit
more adventurous with your modulation,
think about using a pivot note
to take you to another key
and you can have hours of fun
just experimenting with
that kind of modulation
and it will bring many more
possibilities into orbit
and make modulation more
dramatic, more colourful.
