Chords with more than one name.
Polychords (Part One)
Some chords just sound great as open-string shapes. But, what if you were to change or add different lower notes to those chords? These are called “Polychords”.
The “A Minor” Shape.
Today’s lesson will be an introduction to understanding open-string A minor chord shapes with various lower bass notes. These are called “Polychords”. (Some also call them “Slash” chords).
Have you ever noticed that some of your open-string chords sound kind of cool with different lower notes? What are these chords? Are they real chords? Are they legitimate in their usefulness in music? Why do some of these chords have dual or different names?
Yes, these are real chords. They are used in places where they would normally be considered “transition chords”, as they would usually need to be in context for them to make harmonic sense. However, some of these chords sound just fine by themselves.
We will be using the most commonly known shape for the open-string A minor chord.
It is important to understand the structures of these chords and why they have the names they do. The common A minor (Am) (above) requires the root (I - A), the minor 3rd (iii - C) and the perfect 5th (V - E). Some call this the “ACE” chord.
What if we move the low A on the fifth string up one half-step to Bb?
Now, we have an Am/Bb chord. This is a “Polychord”. The Am is the chord and the Bb is the substitution bass note. The “Bb” is the minor 2nd (ii) of A. By itself, this chord really doesn’t sound all that great. Why? Because the structure of this chord has a sort of “tension” built into it. That tension exists in the interval between the Bb and the E.
Diminished 5ths - like the interval between Bb and E, are chords that usually need to be in context for them to have any sort of harmonic resolution.
Here is another way to look at that exact same shape. Wait until you see the name of this chord!
Notice, the intervals between the notes have changed. Now the root note is “Bb”. We now have a BbM7b5add2 (B flat major 7, flat 5 add 2). Yes, that’s really the name of this chord. Major 7 chords with diminished 5ths are not very common chords unless they are being played in context.
So, “Am/Bb” can also be called “BbM7b5add2”. Which chord name would you be more inclined to use? I know which one I’d probably use.
Next we have Am/B. Again, not a real common chord unless it is being used in context.
If we change the interval numbers around and make the B the root note, we have B7b9sus (below). The E has now become the suspended 4th (IV), and the C has become the flatted 9th (ix). This is what some might refer to as an “alternate/extended” or jazz chord.
And last we have the Am/C.
I’ll bet this one looks a little more familiar to you, but maybe not by that name. That’s because this exact chord shape is more commonly known as the C6 chord (below).
Can you see how it is all just a matter of changing the interval postions to change the name of the chord? Any chord can be seen as having more than one name. The more notes you add to a chord, the more names it can have. For this lesson series, we will simply be looking at our regular common open-string chords with different lower bass notes.
Be sure to look for Part Two coming soon. It will be the second half of this lesson - and will include the A minor chord and three of the lowest notes on the sixth string.
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