Yes Chris, that makes sense. Thanks. I have been doing sort of a deep dive into music theory which I'm finding fascinating. Well, everything's relative. A deep dive into the kiddie pool I guess. But it keeps pulling me in deeper. Every time I think I kind of got all I want, there are new questions. One thing I'm finding is that there are a lot more ways that chords can relate to each other than I realized. I thought I probably had a more-or-less complete list of the chords that would typically sound good together with diatonic chords, "borrowed" cords from all the different modes, secondary dominants and even what I have referred to as "God" chords (major chords that are 3rds or 6ths aparts, like C-Eb or E or F# or Ab or A) that have nothing in common but can sound good under the right circumstances (like movie soundtracks in circumstances where the director is trying to create a sese of awe). But no. In your response, you mentioned secondary sub-dominants (is that it for the secondary's btw - like are there secondary sub-mediants for example). Ay Carumba! I'm starting to get the feeling that music theory doesn't tell you which chords might sound good together, in a particular order, but instead just gives you a vocabulary for talking about the chords that do end up sounding good. On another site (a reddit music theory sub-forum), someone wrote that music theory is descriptive rather than prescriptive. Still, I have to think that it's going too far to say that music theory doesn't tell you at all which chords might sound good. As you get further and further away from I, IV, V progressions (where it's hard not to have a decent sounding progression), the options for successfully using out-of-key chords becomes more limited. So I guess this is mostly just me grappling with all this stuff more than a specific question. I guess the question is do you think I'm thinking about this stuff in the right way or am I way off base, out in left field, not even in the right ballpark...to use a series of baseball metaphors?

I'll finish with a more specific question (it's in another post of mine from today that you may or may not see). While noodling around the other day I came up with the following progression: D-F#-G-A. The DGA part of this makes perfect sense but I was surprised that the F# sounded as natural and, to my ear, as pleasing as it did given that it's out of key and neither a borrowed chord from any other D mode, or a secondary dom for the G that follows (it IS a secondary dominant of the vi chord which doesn't appear in the progression). Is there a music theory reason why this sounds good?

Thanks again for your input on the earlier question.

Dave