I Need a New Key! - Transposing Basics
By Ben BlakesleyGeorges Music
We've all been there. This song doesn't work for us in the key in which it was written. Something needs to change.
But how? What is this mysterious "Transposing" that can magically change the key of a song?
It's a lot simpler than you might imagine. No magic involved. Let me explain...
To begin, it's important that you know a tiny bit of music theory. There are 12 Major keys in Western music (we'll stick to major keys for this example), one for each of the notes in the chromatic musical alphabet: C, C#, D, D#, E, etc, etc.
In the key of C Major, the notes are as follows:
C - D - E - F - G - A - B - C
Each of these notes is numbered in the key. So C=1, D=2, etc.
So if you had a musical line that went C - G - F - G, that would translate numerically as 1 - 5 - 4 - 5
Now that you've got numbers representing your notes, you can easily swap out the notes you had in the key of C Major for the corresponding notes in the key of G Major.
The G Major scale is:
G - A - B - C - D - E - F# - G
So our line that is represented numerically as 1 - 5 - 4 - 5 would be G - D - C - D in the key of G Major.
Congratulations! You've just transposed that line into a new key! See, wasn't that easy?
The same concept we just learned for individual notes can be applied to chords with a little more information.
The key of C Major includes the following chords:
C - Dm - Em - F - G - Am - Bdim - C
In the same way that notes are number in order in a scale, chords are numbered as well. But with chords, we would use a Roman Numeral system where an upper case numeral indicates a Major Chord, a lower case indicates a Minor Chord, and lower case followed by indicates a Diminished Chord.
So the chords in a Major Scale can be represented as such:
I - ii - iii - IV - V - vi - vii - I
As an example, let's say you're playing a song with the chord progression that goes C - Am - F - G. This would be represented as I - vi - IV - V.
If you wanted to transpose that progression into the key of G Major you would simply insert the respective chords. The chords in the key of G Major are:
G - Am - Bm - C - D - Em - F#dim - G
So the progression I - vi - IV - V would be G - Em - C - D in the key of G Major.
Hooray, a new key!
The Transposing Decoder Ring
Now that you've got the basics of transposing down, it works like a decoder ring. Just line up the right key and off you go!
As a reference, here is a list of some popular keys so that you can quickly see what chords line up with each other for quick transposing:
Ben Blakesley is in charge of Marketing and Technology at George's Music and studied music and javelin throwing at the University of New Hampshire.