Keys and Chords

[Caleb]

I never knew the theoretical reason, but just as it's somewhat allowed to use the flattened 7th as a major chord, the flattened 6th as major and flattened 3rd as major are also useful to add some color. I assume again it's the number of shared notes -- so in key of C that would be additional bVII Bb major, bVI Ab and bIII Eb.

Just a question here, when you flatten a major triad like you have here, what happens when the original minor triad is on a flat note already, or it is F or C?

Take the Ebmajor scale...

I Eb maj
ii F min
iii G min
IV Ab maj
V Bb maj
vi C min

Now if I flatten the major 3rd, I get Gb major. This is fine.
However, if I flatten the major 6th - what chord do I get?

It looks like a B major to me following the rule, but would it be written Cb major or something weird like that?

And if the major 6th was something like Eb major, would the chord flattened be Ebb major, or just D major?

Sorry if the question is dumb and a bit anal. It probably doesn't matter in the long run, but I just wanted to know how it would be written.

Regards
Caleb

[Toxikator]

Yeah, it's CbMajor/Ebb major. They're called double-flats and they're valid in a theoretical analysis.

The reason it matters is considerations of FUNCTION. The usage of a Cb chord (bVI) is a chromatic mediant, but the use of a B chord (major #5) is different entirely (at least from a progression/modulation standpoint).

Soundwise it obviously doesn't matter, though.

[Caleb]

OK thanks - at least my mind is on the right track. Always a good sign.

Regards
Caleb