Here’s a dangerous sound for us to try out. Get our your guitar, and play this with open position chords.
Dm, G7, C, Dm, E7b9, Am
Play the E7b9 like this:
|-1----| |-0----| |-1----| |-0----| |-2----| |-0----|
That’s the dangerous sound of the dominant seven, flat 9. We used an E7b9 specifically. Here are the notes: E, G#, B, D, F. The b9 is the F in this case.
What is a flat nine? Do you remember how we come up with the assignment of the numbers to the notes of a chord? For our E7b9, the root, third, fifth, and seventh correspond to E, G#, B, D. And going to the next letter name after D, we’d get another E. E would be the 8th note, since D is the seventh, correct? So go one more note: E is 8, F is 9.
The F note is a flat 9, because, thinking in terms of an E major scale, an F# would be the natural nine. Knock that down a half step to F, and you have a flat 9.
What makes this E7b9 sound so dangerous? What is it about that one little note, the b9, that makes us know we’re going into a minor key? Think about what the b9, the note F, is in terms of the key center we’re going to. And then you will begin to understand why the F sounds scary.
Most of the time, when we hear any kind of E7, we expect to hear some kind of A chord right after it. Let’s think about what our scary note, F, is in relation to that “some kind of A chord.”
The F is the b6 of two very common minor scales: the A Natural Minor scale and the A Harmonic Minor scale. A major scale does not have a b6. Therefore, when we hear the F in the E7b9 chord, our ears say “whoa: minor key center coming up.” That’s one reason why the E7b9 sounds dangerous: it’s giving us a sneak preview into the somber sound of the A minor key center coming up.
Digest that point for bit. Then try this progression.
Dm, G7, C, Dm, E79, Am
Same progression as before, except for the E natural 9. Play it here:
|-2----| |-0----| |-1----| |-0----| |-2----| |-0----|
That was an E9 with a natural nine to it. When we hear that E9, it doesn’t sound as dangerous as the E7b9. The reason is that the natural nine will become the major 6 of the next chord: F# over a chord whose root is A; and our ears are more accustomed to associating the major scale, not minor, with the natural 6. So when we hear that F# in the E7, we think, “Hey, we could be going to a major key center next.”
More on the dom7b9 next time.
Thanks for reading.
Copyright © 2008 Darrin Koltow
This first appeared in the Guitar Noise News – June 15, 2006 newsletter. Reprinted with permission.