OK, I understand what you mean. I'm listening to my A1 as I write this..and although I use the N3 mostly, I still use my A1 pretty much every day - out walking and stuff. To me they still sound good, certainly smoother and less extended than the N3, a bit less natural sounding, not "exciting" and maybe that gets boring
but I prefer that to some other brands which have excess bass or hot treble trying to make up detail.
I only auditioned the N1, my impression was that they were more "powerful" and "richer" than the A1, but not nearly as clear as the N3.
Honestly, not sure they are enough of a step up from the A1 to be a definite upgrade, certainly not for me. (But I paid $190 for my N3, got very lucky so it was an easy choice
)
Of course the N1 have detachable cables and are more comfortable, so that's an upgrade, but sound is more difficult to put a value on. Sorry this doesn't help so much...