My question is a general curiosity because on StackExchange and other sites I haven't found a complete answer that I can get my head around. I've read through the existing 13th discussions and am still just not getting what I'm after.
I get basic major and minor 13ths but when I get to something like this:
[1 ♭3 5 ♭7 9 11 ♭13]
Which in C is [A C E G B D F]
Is this an:
- Amb13 (A-♭13) which seems to fit with Am11 adding a ♭13
- Am11add♭13 (A-11?13) no idea what a shorthand for add might be as + is usually augmentation as I understand it so Am11+♭13 wouldn't make sense
- Am11b13 (A-11b13) (reading as Am11 with a flat 13th on top and no "add" required)
- some kind of mutant hybrid like Am7dim13 A-7o13 (reading as A C E G + B D F)
- A minor-major 11♭13 (A-^11♭13)
- An ever stranger slash chord like Am/G7
I know these aren't in common practice but is there any standard guidance on naming of 13ths with varying mods to the upper tones? I'm coming at this assuming it's all the tones starting with the root through to the 13th and you aren't playing with inversions.
Are these alterations? Extensions?
When naming do you:
- stop at the 7th and treat it like a 4+3 note polychord even though I believe that is generally reserved for two triads?
- stop at the 9th and add alterations to the 11th and 13th?
- stop at the 11th and add alterations to the 13th?
Apologies for the mind dump. Just throwing out a list of every direction my mind has gone in with this topic.
Any reference or guidance would be appreciated.