Bitonality with major sevenths

I now want to begin looking at the topic of putting chords on top of other chords. This general area is called polytonality. Polytonality means sounding different keys at the same time. We’re interested in bitonality - sounding 2 keys at the same time. More specifically, we’re going to be looking at putting triads over our basic jazz chords. To be specific, let’s look at the major seventh. I’ve said that the major seventh is a very strong sounding chord. The scale that goes with it is the usual Ionian scale. In a way there’s not a lot you can do with it.

In fact, if you come across a major seventh in a chord sequence the likelihood is that, even if only temporarily, the piece has modulated to that new tonal centre. Let’s be specific. What I want to do is what I call “Lydianising” a major seventh, that is sharpening the eleventh. If I take C major7, then the eleventh is F, the sharpened eleventh is F sharp. If I put that in the context of a triad and take D triad then, in terms of chords over other chords, it’s D triad over - D, F sharp, A - over C major7 - C, E, G, B.

If I’m playing it as a final chord, then I play C major7 at the base, and then I put D triad over the top. If I want to improvise over a scale, then the scale I get is what I get if I just sharpen the fourth,

which is a mode of G major

the Lydian mode. This is something I do if I want to create a bit more colour for a major seventh - then I Lydianise it - I sharpen the fourth. An example occurs naturally in Dave Brubeck’s “In Your Own Sweet Way”. If you look at the last 8 bars of the tune.

So that is the sharpened eleventh - although it does actually move to the fifth. You could keep the sharpened eleventh in the improvising. For example, if I just take the last 4 bars. 1,2,3,4.

I’m still playing B flat major7 in the left hand, but I’m putting in the Lydian scale and, very often, I use the triad. So I go up a tone from the underlying scale (chord). If it’s B flat going up a tone takes me to C and so I’m going to play C triad. If it’s E flat I go up a tone and I get to F. I quite often use that. Something I use rather rarely is to look at E triad over C major7. So you get this sound. Or if you were to finish with something.

Then the scale that goes with it is C major with a sharpened twelfth in it - sharpened fifth, if you want. It isn’t really a sharpened fifth - in the scale it is - but it’s not a sharpened fifth as a chord, because we still have the fifth in the underlying chord. But the scale that goes with it is

which is A harmonic minor. Notice, because it’s a harmonic minor, it’s got a minor third in the scale. So I could use that. I could also use the 2 together, that is sharpened eleventh and sharpened twelfth. I’m not sure there is a notation for it, but E triad and D triad over C major7, or C major7 with a sharpened eleventh and a sharpened twelfth - I guess, if you wanted to indicate it. But I could play and the scale that goes with it, if I wanted to improvise on it, would be

which is A major with a flattened third, so it’s A melodic minor ascending.

OK, you could look to see if you felt any other major or minor triad gave you something new - gave you something interesting over C major7. I personally don’t think it does. I mean, just quickly looking at the major triad. That’s nothing new if I take C triad. If I take D flat - C sharp triad then I’ve got the fourth against the third, which is a pretty horrible sound because it’s a minor ninth. Similarly, I’ve got the sharpened twelfth against the fifth - another minor ninth. That doesn’t work. D triad we know about. E flat triad - there we’ve got E flat against E - sharpened ninth (major seventh). We’ve also got B flat against B.

So it’s like 2 of the notes of the fundamental chord are undermined. I don’t think it works to my ear. E triad we’ve considered. F triad - again we’ve got minor ninth in there. It doesn’t really work. F sharp triad, the B flat undermines the B and the D flat undermines the C. Two notes that undermine the basic chord I don’t think works. G triad is just notes that belong to the fundamental chord, if you add the ninth. A flat triad - again minor ninth and - sorry - yes, minor ninth and major seventh. It doesn’t really work. A triad - A triad doesn’t sound too bad.

So how would we interpret that? Well it’s got a flattened ninth in, so it would be C major7 with a flattened ninth. Off the top of my head I can’t think of any tune that has that chord in. It may well exist. That’s not too bad. A triad - B flat triad doesn’t really work because you’ve got B flat against B, F against E. Similarly, B triad - I don’t know - you’ve got E flat against E and F sharp against G. I think if you try the minor triads you, basically, don’t get anything new. If it sounds OK, it’s just a variant of a chord we know about already. So that’s bitonality with major sevenths.