By Walt Palmer Guitar Instructor the Rock and Pop Music Academy
In my last guitar lesson we talked about improvising and playing the 12 bar blues. Today’s article will expand on this idea but talk more about chords and how to change a song from one key to another.
Anyone who writes songs, or improvises, or composes symphonies can tell you that one of the most important things to know is the array of chords available in any given key. This knowledge should be foundational for any musician.
Being in a particular key means that all of the chords and melodies are taken from a specific scale. For example, playing in C Major means that all of the chords and single notes come from the C Major scale:
The Chord Scale
If we stack these notes in 3rds, the way chords are built (Root, 3rd 5th) then we will get a combination of Major, Minor chords, with a Diminished chord as well:
The chords within any major scale will all have the same pattern of qualities: The root or Tonic Chord is major, the second and third chords are minor, fourth and fifth chord are major, sixth is minor, and seventh is diminished.
For ease of reference we use Roman numerals to indicate the chord quality:
I – ii – iii – IV – V – vi – vii – dim
Upper case Roman Numerals indicate that the chord is major and lower case indicates minor, and diminished. Again, this pattern of chord qualities is the same for ever major key: G, D, A, E, etc… The only difference would be the root notes. So even if we play in the key of Cb major, we still know the pattern is the same as in C major.
With this information we can start to look at songs differently. Instead of focusing on the key that’s on the page, we can understand it in terms of the chord progression used based on the chord number and not on the chord name (i.e. I – IV – V – ii – V -I).
A standard blues, for instance, always uses I – IV – V – I, and so it’s extremely easy to transpose the blues to any key once we know the chords for that key. But let’s look instead at something that is not blues.
A great exercise is to pick up a simple song book at your local music store and pick a song to analyze and transpose.
Here is an example of how to analyze a song and transpose it to another key:
LET IT BE – THE BEATLES
||: C G | F Amin |
| C G | F C :||
The song is in the key of C and this chord progression would be analyzed as:
I – V | IV – vi
I – V | IV – I
Knowing this, I can easily transpose this song to a new key, for example the key of G:
G – A – B – C – D – E – F# – G
so we can see that “Let it Be” would be transposed like so:
||: G D | C Emin |
| G D | C G :||
I can take it even further and improvise over this progression in the key of G, even substitute these chords for new ones (which is a much more advanced discussion for a later time).
Knowing your chords within each key is fundamental to becoming a good musician. Practicing transposing your favorite songs is the best way to begin understanding this concept.
How has music theory helped you take your playing to another level, or explore new sounds and chords?