Amos: my bad -- I wrote "subdominant" where I should have said "dominant." Also, you were *way* more concise than I, for sure.

Of course, we don't know for sure whether the blues-harp deal is even an issue for guest IanN. I just guessed that it might be part of what he was confronting because (a) he mentioned playing with harmonica players and (b) he was confused about using a capo, which I always considered (even as a rank beginner) a pretty simple concept unless some additional problem were muddying the waters.