From a "Hidden" Augmented Triad to an Exotic Scale

I stumbled across this while playing around with augmented triads on minor chords and thought it was at least a little bit interesting, if only because it led me to a scale I haven't come across in a musical context before.

One of my favourite things to play on a static minor chord to inject some dissonance is the Neapolitan Scale, which is really just melodic Minor with a b2: 1 b2 b3 4 5 6 7. Another way to think of this is to notice that b2 b3 4 5 6 7 is a whole-tone scale -- the one that doesn't contain the root of the chord. So the idea can be summarized as: on Cm, play Db Whole Tone and resolve to C. That's how I tend to think of it.

Once you've been doing this for a while something else will probably jump out at you: the Whole Tone scale contains two of the four augmented triads. In this case we're playing b2 4 6 and b3 5 7, which translates into Db+ and Eb+ over Cm. Augmented triads are easy to play and very distinctive-sounding, so this works nicely.

Now, that's two of the four possible augmented triads: what about the other two?

One is 1+ (i.e. C+), and you only want to play that over Cm if you're sure you know what you're doing; the major third in C+ needs careful handling on Cm. It can be done and be made to sound really modern, but it's very much its own thing. I would probably think of this idea in connection with playing C Altered (i.e. Db Melodic Minor) on Cm, which you can think of as being 1 b2 b3 b4 b5 b6 b7 -- looks like a minor scale, right? Just watch that b4. The augmented triad doesn't pop out in this spelling: it's 1 b4 b6.

The other is the "secret" one: 2 b5 b7. I don't think this is an obvious thing to play at all, but it sounds pretty interesting. Can we think of it as part of a bigger structure that helps us build more vocabulary around it?

Well let's see what happens when we play 2+=2 b5 b7 over 1m=1 b3 5. Altogether the notes we're playing are 1 2 b3 b5 5 b7. It makes sense to respell it as 1 2 b3 #4 5 b7. That's six notes -- do they look familiar?

If you know your Harmonic Minor modes they will: 1 2 b3 #4 5 6 b7 is Dorian #4, a scale you already know. That's great; this "new" idea, 2+ on 1m, connects with an "old" idea, the Dorian #4 scale.

But the 6 isn't the only note we could add. What about 1 2 b3 #4 5 b6 b7? That's the scale I call Shanmukhapriya, after the Carnatic melakata of the same name. It's a mode of a major scale with a #2, specifically the one built on the b3.

One way to think of this idea, then, is to play Eb Major #2 over Cm7. Or you can learn the fingerings as their own thing, which I always recommend if you're going to be using a modal idea in real life:

All these augmented triads are coming out of my engagement with Scriabin and Xenakis a few weeks ago; there's (at least) a bit more to follow.