dazzerfong
1000+ Head-Fier
As it currently stands the former would be not possible. The Z1R is entirely dependent on that 12mm DD and there’s simply no way to shove that into an M9 shell. You would essentially need a much smaller DD (which Sony have their qualms about, DD diaphragm size is very important to them) in order to fit that form factor.
It's not so much the fact that it's bit - it's the shape. 64 Audio stuff is BIG and yet they aren't ridiculously uncomfortable.
I suppose that's the compromise we have to deal with - comfort or sound.
Funnily enough, the sales staff dissuaded me from the MDR-Z1R. They all have an obsession with the IER instead....