Expanding your Chord Repertoire
So you can now play the A minor and C major scales of trichords, by taking the scale and playing notes 1-3-5, then continuing with 2-4-6, 3-5-7, 4-6-8, 5-7-9 (I know, it’s really a 5, 7 with a 2 on the next octave up, but we call it a 9 anyway, for continuity), and so on.
There are two different techniques for messing with chords. Expansion and Substitution. Expansion is simply adding extra notes to make a tetrachord (a 4-note chord) using other notes from the scale. Substitution is playing the same notes, but all mixed up!
When you start adding notes to the trichord, it becomes a tetrachord. Since the basic trichord is 1-3-5, we’ll start with the next logical note, the seventh.
So take four fingers and hit the C, E, G, B notes. That’s “C major 7th”, or CMj7. Now try A, C, E, G. That’s Am7, or “A minor 7th”. Pretty easy so far.
Now, run up the A minor scale of chords, using 4-note “seventh” chords. Do this slowly, so you can hear the difference.
If you remember from previous lessons, our “matching” chords were the one, four and five. Every part of a scale has it’s name, and in a major scale, the number 1 is called the root, or tonic. The five is called the “dominant” chord, and the four is called the “subdominant.”
Play a little progression of chords using the I, IV, V (one four, five) chords (so C major, F major and G major), but adding a 7th in the scale, remembering only white notes. The dominant 7th chord is strange here. Remember the difference between the major and minor “leap”? The dominant 7th chord has a major trichord, but what seems to be a minor 7th note hanging on there. It sounds like it’s waiting for the next chord or note…
This dominant 7 is simply called G7 – presumably as it’s not major or minor! In fact, if you use these dominant 7th chords as your I, IV, V progression, you’ll be playing standard blues chords. Try making a C7. It’s a normal C major 7, with the 7th note shifted down onto a black key. Same with the F7.
Try out a simple 12-bar blues progression in (sort of) C major:-
Each bar goes 1, 2, 3, 4. So, for instance, C (…2, 3, 4), C (…2, 3, 4) and so on. Just play the first three bars as a normal trichord…
C, C, C, C7, F7, F7, C, C7, G7, F7, C7, G7 (…and repeat!)
So that’s sevenths. There are other tetrachords you can make progressions out of. Try 6ths. It has a different feel. There’s also 8th and 9th chords.
If you’re playing trichords with your left hand and run out of fingers, there’s a couple of things you can do. You can miss out the 3 note of the chord, and play a 3rd further up with the right hand as part of the melody. Or you can do the same with the 7th note. Play it as part of the melody, missing it out on the left hand, hitting it on the first beat of the bar with the right hand.
So next time you see a CMaj7, or a G7, or a Fmin7, or Amin9 written somewhere, you’ll know what it’s talking about. You should also try writing a small tune using four-note chords and a melody.
You will have noticed from the last lesson that it takes a bit of thought to jump up and down the keyboard. Luckily, there’s an easier way of jumping from one chord to another. Let’s try it with our I, IV, V chords…
The first is a C major chord. Nice and easy trichord. Now play the IV chord, F major. It’s a bit of a jump, but try to notice which notes are the same, and which are different. C major has C, E, and G. F major has F, A, and C. So C is the same, just played an octave up from the I chord to the IV chord.
So play a C major chord. C, E, and G. Now, leaving the thumb on the C, move the two fingers across from E and G, to F and A. That’s all a substitution is. C major to F major goes like C, E, G to C, F, A. Then, to get the V chord, simply move up to D, G, B.
Even though the chord sounds similar, it is reshuffled. As the root (or lowest) note has now shifted, it’s actually a different chord, but it sounds the same as it has the same notes. Sometimes you’ll want to do this, as it can be easier to play, but sometimes you’ll want a more definite chord change so you’ll just move the whole chord shape up the scale.
This is a great way to acheive major 7th chords, so take your simple progression with expanded chords, and see how many substitutions you can make. Try writing a IMaj7, IVMaj7, V7 progression (I, IV, V with 7ths), for the left hand, using substitutions and missing out notes from the chord. How many chords can be found just a note or two away from where your hand is already?
An expanded chord is a normal trichord with another note added for extra flavour. 7ths, 4ths, 6ths and 9ths are popular.
The C Major 7th chord can be made with 1,3,5,7 on the C Major Scale. The A minor 7th chord can be made with a 1,3,5,7 on the A minor scale.
A simple “seventh” can be made with 1,3,5,7 on white keys starting with G. Also known as the dominant 7th (since G is the “dominant” note of the C major scale!)
A substitute chord is a normal chord (trichord, tetrachord or just a mix of notes!) shuffled around so the root (or lowest note) is different. It’s still the same basic notes. This is to make it easier to play, or to make a more subtle sounding chord change.