[Miguel Dominguez]

Looking for something to replace my B&O H6 v2. These have been great cans, but I'm looking for something with a bit more neutrality and spaciousness to the sound (preferably closed). I find these phones can be a bit fatiguing after a while.

Consdering:
Oppo PM-3
Audeze SINE w/ Cipher

 

[Luminance]

Oppo PM-3 has neutrality, but lacks of spaciousness. Good choice though.
I would not risk getting on-ear headphones without trying them first due to comfort. I made mistake of buying Beyerdynamics Custom Street on-ear and that was horrible experience.

Sony MDR-100AAP might be something you're looking for.
Momentum 2 (wired) could be another option, but they are not very neutral.

 

[serman005]

I personally find the PM-3 to be so neutral as to be a bit on the boring or lifeless side of things. Just my take and YMMV, of course. I would personally prefer the HP50 to the PM-3. I would also consider the Senn HD1--a good option. Lastly, I really like the B&W P7 for your purposes. It could work for you. Maybe read about these and see what you think. It is possible one could work for you.

 

[Miguel Dominguez]

Thanks for the recommendations! I'll have to read up on these.

 

[cossix]

The HD1 isn't very neutral but it's not fatiguing at all. Great detail with a fun sound to them