The Dangers of the "Key Center"

You've heard it a million times: "find the key center".

If you're not familiar with the concept (and I'd find that hard to believe), it boils down to, "play in the key that best fits the chord progression you're soloing over." Almost every guitar player I know goes at improvisation this way. Teachers tell you to do it, books tell you to do it. But is it right?

I'd have to say, sometimes, but for the most part, it's a dumbed down version of the real deal.

Consider the following progression; "Blues in A". That's going to be a I IV V progression (forget things like quick change and such now, that's not what I'm talking about here). So, your typical guitar player leading it will say, "So it's A, D, E".

Ok...first, that's not enough info. Maj7? Min7? Dom7? Just use the 5ths (power chords)? There's all kinds of blues, the variety is endless (consider "The Thrill Is Gone"; that's pretty basic blues, but if you use Dom7 chords for everything, you're not playing the song correctly). Asking for this clarification seems to frustrate a lot of guitar players, but tough Toblerone, I want to know.

You get the condescending eye-roll and "dominant 7" reply (if the guy actually knows what a Dom7 chord is). So, A7, D7, E7. Right away, you say, "Ok, I'll use A to solo over it."

"A" what? If you know a little about modes and chords, you know a dominant chord is a major chord with a b7; so you're going to think Mixo (let's forget about subs, variations, and whatnot, keep it basic).

So, A mixo; A, B, C#, D, E, F#, G. I've got it, I know how the other modes connect to it up and down the neck, I'm ready to go, kick it over professor.

You're moving along nicely, got your major third and minor seventh going, you're a master of modal improv, flying all over the neck. But then the progression goes to the D7 (D, F#, A, C), and you hit the C# in your A mixo scale. You know it doesn't sound right (especially if the bass player is using the b7 from the root, which is very common), but you want to stick to your key center, so you fudge it, slide or bend or whatever. You're still alright, hey it's a "passing tone."

Now you go to the E7 (E, G#, B, D), and C# seems ok again, but you hit the G in A mixo. OMG something is wrong again, wtf is going on?

Then you do what most guitar players do when they're lost; you slide into the minor pentatonic scale. So you futz around with A pentatonic minor, bending liberally, and finally get out of your solo. Dang why don't I sound like all those great players, I was using the right mode...

...it's because you weren't using the right mode. Well, you were, but only over one of the chords. The key center concept failed you, because it's not enough.

Check it out:

A7 = A mixo = A, B, C#, D, E, F#, G
D7 = D mixo = D, E, F#, G, A, B, C
E7 = E mixo = E, F#, G#, A, B, C#, D

The scales aren't drastically different, true, But assuming that any one of them will fit over all three chords is simply a mistake. You have to be aware of what notes don't fit (or rather, just make sure you are playing notes that do). Many great players may not actually know the science behind it, but they definitely DO know that the same scale doesn't work over all the chords, so they make the adjustments in their head, frequently just be years of hearing what sounds right and wrong, they remember it, and use it as needed. Note that this sort of player frequently does have a homegrown system of some kind and they work VERY hard at recognizing and cataloging "good" sounds.

Academically though, the more advanced way to think of this is: FOLLOW THE HARMONY (harmony = chords). That's how your solo will sing, and sound right. Always know what chord is under you, and if you're totally lost, don't just start wanking in a minor pentatonic scale; try to use your ear, stick to the roots, ninths and fifths (a ninth and a fifth is a pretty safe bet unless you're playing altered chords, and if you're playing over that kind of harmony, you've probably already stopped reading), or, STOP PLAYING (an option frequently forgotten).

Note that a key center can work well under certain conditions. If all the chords come from the same key, then it's great. In terms of the progression we mentioned before, that would be Amaj7, Dmaj7, E7, over which you'd play (at a fundamental level) A Ionian, because all the chords are from the A major scale. If they're Amaj, Dmaj, E7, you're fine too, now you're just leaving out the sevenths (which actually gives you some additional flexibility; this is a very common rock characterstic, using Mixo over a straight Major chord, look at guys like Neil Schon for some real mastery of this). If you're just using power chords, then you can make just about anything work, because now you don't have any thirds or sevenths to worry about conflicting with (though you should still understand what sound you're trying to get...happy major, gritty rock/blues, etc.).

However...if the chords are Amaj, Dmaj, Emaj, you have the key center problem again; Emaj isn't diatonic to the A major scale (you're raising the 7th of the chord, from D to D#, and D# is not in A major). But, D# is the #4 of A major, which puts you in A Lydian. Ionian and Lydian, although very different in terms of modes, are commonly mixed freely, subbing one for the other. So the effect can be interesting and probably won't train wreck. But you need to be conscious of it to really make it effective.

The more I solo, the more I force myself to acknowledge the chord I'm playing over to ensure that I know where I am. I try not to take anything for granted, and when I catch myself thinking in key centers, or slipping into default minor pentatonic, I know I'm either being lazy or just don't know enough about the arrangement, so I start listening, trying to use things I know fit over certain sounds, stick to the safety notes, and try to wind up my lead in a reasonable spot so I can get out without breaking anything.

As always, thanks for visiting.