The three principal chords and scales of jazz

Now in jazz as well, there are three principal chords. The analogue of the major triad is called C major 7. It’s a four note chord, which consists of the major triad at the bottom to which you add the major seventh. The scale that goes with it is the same scale that goes with C triad, namely the Ionian scale – the “do-re-mi” scale.

In classical music, this is sometimes thought of as a dissonant chord because it has B in it and the B and C give you a crunch sound that sometimes isn’t very pleasant.

But in jazz, we’re very used to that sound. If we finish something and the final chord is C major 7,

then the B natural is a very pleasant sounding device.

Then the analogue of C minor triad is:

and this time we add to it the minor seventh, the flattened seventh B flat, and that chord is called C minor 7. The scale that goes with it? Well the way I like to think of scales generally is to relate them to the Ionian scale, the Ionian mode. And so what we’ve done to get this chord is to flatten the third and flatten the seventh. If we do that to the Ionian scale, flatten the third

and flatten the seventh, we get:

Indeed that is the most used of the four possible minor scales that exist. That’s the most used in jazz and it has the name of the Dorian mode. It’s called a Dorian mode because, in fact, it’s B flat major scale rooted on C. Hence it’s a mode, but we’ll look at that in more detail later on. What I’d like you to remember is that you take the major scale, you flatten the third, you flatten the seventh, and that gets you your principal scale of C minor seven. Then we come to the third chord, which in classical music is called the dominant seventh because it’s a passing chord. It takes you to the tonic which in this case is F.

But as we know, in jazz C7 is the blues chord. It is one of the most important chords because it is the basis of the blues.

If I play a blues and the final chord is:

it does not then have to move to F. What’s the scale that goes with it? Well we know that we can have the American blues scale,

which consists of the root, the flattened third, the fourth, the flattened fifth, the fifth, the flattened seventh, and the octave. And the advantage of that, as we’ve seen, is that you can use that one scale throughout the whole of the blues sequence and it simplifies things greatly. However, we also have available to us the 7th scale itself which is taken from the Ionian scale. and is what do you get when you flatten the seventh.

Indeed, we can add the Ionian scale itself

with the natural seventh. So what we get if we take those three scales and we superimpose them, is this scale.

In fact, it’s sometimes easier to say which notes are not included. The notes which are not included in the full blues scale is D flat (in this case) which is the flattened second, and A flat, which is the flattened sixth. In fact, in some contexts, you can include those notes as well. But as far as the full blues scale is concerned, they are missing. So we have all these notes. But we have to be a little bit careful about the major seventh. Because

when we play the major seventh with the underlying chord of C7 we get a discord, a rather nasty discord, including an interval of a minor ninth. And a minor ninth, generally speaking, the ear just doesn’t like.

You know, you get this Les Dawson effect: so how does it go now?

So if you just put your hands on the keyboard and play a random set of notes and it doesn’t sound all that nice, it’s very often because there is a minor ninth in there somewhere which is causing the ear to reverberate. However, the major seventh is in but it needs to be used with discretion. When I write out the scale, I often put the major seventh in parentheses to say it can be used but it must be used carefully. It must be used as a passing note. You can’t finish a phrase or important line with that note. It’s used to get up to the tonic or the minor seventh – the flattened seventh.

There is one very nice example of this (of using the major seventh in a blues) and it’s by Charlie Parker called “Au “Privave.” This is blues in the key of F.

And I’ll just play the tune.

Now the very first phrase has got the major seventh in it. And then the third phrase

has again got the major seventh in it.

And later on, there is one bit (at the end) that goes: You see, it’s taking you to the tonic note.

So the major seventh is in, but it must be used with caution.