Benjamin, I think we can resolve our misunderstanding.

The first line of your original post read
"Man, I'd forgotten all about those N6 chords"

I assumed this was a deliberate attempt at irony on your part ("N6 chords"?) but I now realise that it was a typo. Hence my response,which was in fact intended to be jocular...

But, when we get to GUEST'S post

"Diminished 7th beginning on F.

F Ab Cb Ebb(E double flat)"

I'm outta here, but fast ...

Murray