Common Triads and Forte 3-3
Continuing my look at 3- and 4-note sets that aren't common in diatonic music, we arrive at 1-b2-3, the "Phyrgian major" or "Harmonic minor" triad. first here's the usual full-fingerboard diagrams: chords are formed by playing one note of each colour and dark blue is the root. The top one is 1-b2-3 and the bottom is 1-#5-7, its inversion; these are Forte number 3-3:
One way to use this is as an "ornamentation" on a triad. For example, here I play a major triad but every note is replaced by a 1-b2-3 (bar 1 is the triad, bar 2 the ornamented version and bar 3 the same notes gathered up into a scale):
This is an idea I explore a lot more in my Slonimsky book. It's easy to do and can lead to interesting melodic ideas that aren't obvious otherwise and that have a nice inner consistency because of the way they're constructed.
The major triad ornamented by 1-b2-3 in this way produces a Double Harmonic scale (1 b2 3 4 5 b6 7). Doing the same with a minor triad gives 1 b2 b3 3 5 b6 7, which is a mode of Neetimati. The same on a diminished triad produces a mode of Ramapriya. All these are heptatonics.
Using the inversion, 1-#5-7, as the ornament instead changes some things. On dim triad we get Melodic Minor b5 (1 2 b3 4 b5 6 7), a different mode of Ramapriya from the one we got from 1-b2-3. To make the two match and produce the same notes, just build the ornaments on diminished triads a tritone apart. There is a little "system" here that is worthy of more exploration.
As for the major and minor triads, 1-#5-7 yields exotic eight-note scales. On the major triad you get what might be called a Suvarnangi with an added major third, while on the minor triad you get Lydian with an added minor third. Both of these could be interesting but I don't see any obvious relationship to their 1-b2-3 counterparts. There's no reason to expect one, really, but playing and listening might well turn something up.
On an augmented triad the picture is different again. 1-b2-3 produces the six-note Augmented Scale, 1 b2 3 4 b6 6, whereas 1-#5-7 produces a mode of the nine-note scale I call Triple Chromatic: 1 b2 b3 3 4 5 b6 6 7. Unsurprisingly, these are both symmetrical scales.
This has been a bit of a paper exercise so far. I'm definitely interested in exploring the diminished versions but there may be other things to look at here too.