How do
transposition and modulation relate? Are they the same? In this
newsletter we're going to take a look at both of them and see
what makes them tick.
I'm sure that you have had the
experience sometime in your piano-playing life when someone asks
you to play a song -- but in a different key than in which it is
written. It might be a singer wanting you to lower the song a
step so he/she doesn't screech. It might be a song leader
wanting you to play a song in a more comfortable keys for a
congregation or group. It might be a trumpet player looking over
your shoulder and wanting to play along with you -- but when
he/she plays the same note you are playing, it sure doesn't
sound the same!
So....it's your job, as pianist, to
get that song moved to a different key. That's transposition --
playing or writing a song
in a different key than in which it was originally written.
Modulation is
similar but different -- modulation means the process of
getting from the old key to the new key. In other words, if
I'm playing in the key of C, and then want to play in the key of
Eb, I have to learn to modulate -- move smoothly from one
key to another without being too abrupt and jarring.
There are basicly 3 ways to transpose:
1. by intervals
2. by scale degrees
3. by solfege -- the moveable "do"
system.
But since solfege applies mostly to
singers, we will ignore that possibility and just take up the
first two:
1. Intervals: If the new key is an
interval of a minor 3rd above the old key, then all notes in the
song will also be an interval of a minor 3rd higher. In other
words, if you are transposing from the key of C to the key of Eb,
which is a minor 3rd higher (or major 6th lower -- whichever way
you want to look at it), then all melody notes will also be a
minor 3rd higher:
"G"
in the key of C would become "Bb" in the key of Eb. "E" in the
key of C would become ":G" in the new key of Eb. "A" would
become "C", "B" would become "D", and so on. All chords would
also move a minor 3rd higher. The "C chord" would become the "Eb
chord", the "F chord" would become the "Ab chord", and so on.
2. Scale degrees: Each key you play
in has it's own scale degrees. In the key of C the scale degrees
are: C=1, D=2, E=3, F=4, G=5, A=6, B=7, C=8. In the key of Eb,
however, Eb=1, F=2, G=3, Ab=4, Bb=5, C=6, D=7, Eb=8. So if I
want to transpose Silent Night, for example, from the key of C
to the key of Eb, I need to notice what scale degrees I am using
in the key of C, and then use those same scale degrees in the
key of Eb. For example, Silent Night starts on the 5th degree of
the scale, goes up to the 6th, back to the 5th, then down to the
3rd. In the key of C that is: G-A-G-E. But in the key of Eb it
is Bb-C-Bb-G. Why? Because the scale degrees 5-6-5-3 are
constant -- we just need to apply them in each key. What about
chords? Same idea. If the chord progression on Silent Night is
the I chord followed by the V chord, followed by the I chord,
followed by the IV chord, etc. -- then in the key of C that
means C-G-C-F-etc., but in the key of Eb it means
Eb-Bb-Eb-Ab-etc.
Modulation means getting between
keys, so let's say
you are playing in the key of C, but you want to get to the key
of Eb smoothly, without jarring the nerves of the listeners.
There are lots of ways to do it, but the main point is that
you have to get to the V7 chord of the new key. So from the
key of C to the key of Eb, that means getting to Bb7. How do we
do that smoothly? We look for chords with common notes. Since
the V of the V of the new key would be Fm7, we have C as a
common note. So we hold the C in the C chord, and move the rest
of the C chord to Fm7, then Bb7, then Eb, and presto -- we are
there! I realize that may be a bit hard to follow with just
printed words to follow, but if you saw it happen (like on a
video) you would understand it instantly, I think.
Hope this has helped you understand
both the process and the difference between transposing and
modulating. For those of you that would like to follow-up on
this in depth, you can click on this banner:
