Thanks for your reply. I would like the headphone to be portable as well. I want to use it with my ipad or samsung android phone etc... and because of this, I guess low impedance would be better.... no amplifier; size does not matter. This would be my first higher-end headphone for listening...

I am in the market to buy a new headphone and I am debating between the Sennheiser Momentum or the Beyerdynamic Custom One Pro.  I am interested in the better sound  quality  and I do  not mind price difference or size or design etc....... I just want the better sounding headphone. I was able to...