Get this (and I doubt OPPO would have any problem with me sharing this): To test the PM-2, they sent us replacement pads and a replacement cable - to convert our PM-1s into PM-2s. Pads and cables are the only PM-2 parts that could possibly have any impact on distinguishing the sound of the PM-2 from the PM-1. Seriously. That's it. The drivers are identical. The PM-2 drivers are the PM-1 drivers.
If you were to buy a PM-2, then attach your choice of PM-1 pads, plus the PM-1 cable, you'd be left with frame and headband differences that could have no impact on sound quality any moreso than the wood presentation box, the denim carrying case, etc.
VEEEEEERY interesting !
On the one hand, doing this approach would make one worry about the "halo effect." Testers KNOW that the cans on their head, or at least the drivers and the immaculate finish, are the PM-1s, and that could color their judgement.
On the other hand, if the internal working parts are identical, then the null hypothesis for testing (so to speak) *should* be that the PM-2 sounds exactly like the PM-1, unless the cables and ear pads make an audible difference.
If the general consensus agrees with this:
then the soon-to-arrive PM-2 is going to cannabalize the heck out of PM-1 sales, long before they would normally crest.
Since Oppo has to know this, clearly the PM-2 is being positioned as the world beater. And while the PM-1 is priced above the new HE-560s, the PM-2 would have a price advantage. Gonna be interesting. Exciting times to be a headphone addict. (Sorry about our wallets.)