I don't have that much time tbh. Looking up for prefect set of cans can be painful. I need one solid recommendation "get those, they will be good". Thanks for your answer, much appreciated. I know that HD600 are not for me.
If you have some time, you can look this up. http://www.head-fi.org/t/815458/upgrade-over-hd555-something-else-need-change#post_12751462
I'm not a hard reviewer or anything. But I've had my share of experiences with high end headphones. I owned the original momentums, I felt they were very good headphones, but in the end I wanted open headphones at that time.
Since then I've sold all my open headphones, and I now own the M2 wireless and Fostex TH-900. The Fostex has sort of ruined all cheap headphones for me. I was in for a new portable pair since my girlfriend jacked my sony's, so I tried a decent amount of low end say ~$100 ish headphones. I saw that the momentum came in a wireless version so in the end I decided to buy from best buy due to their easy return policy if I didn't like.
I believe that the M2 is the best bluetooth headphone in existence. If you're coming from any sennheiser hd 5xx I think you'll notice a healthy low end that's less defined due to it's extension and fullness, none of that tinny stuff, and not unbalanced in a way that ruins the headphone. It's a good thing. I'm not talking overbearing bass, or muddy bass, the headphones are well balanced. For some people, they prefer the other way, as it works for them for acoustic / jazz / classical. Some (I can't say how many, just some that I've talked to) of those people just don't like bass period.
With the M2 I feel it can play all types of music just as well, it's just that people who prefer to listen to ONLY those genres are more in for that older, open sennheiser signature.
If you're looking for something different from the 555, this will be different. I think compared to open headphones, once again generalizing, closed headphones have a unique thing going with their sound stage, especially when music is panned fully to the left and right and there's a lot going on, the m2 is really great when that's happening (something that is mostly unique to electronic music).
Going off memory, I might most most closely compare them to the Paradox or original Mr. Speakers mod. The difference being mostly in the sound signature, but keeping the other attributes like staging and separation, with very good, but not quite as good accuracy, with M2 wired being of the better value. Those others are more like studio monitors, which IMO are not good for music listening, but great in the studio (which is why I don't like the senn 5 series either).
I agree that looking for a 'perfect headphone' is awful unless you're a person who's just on that quest for your own personal reason. I can respect that for sure. I just want to listen to music man.
Would I recommend the M2 for you?
Absolutely, like many on here it's
a very good headphone.
Is it the kind of difference you are looking for?
Most likely.
I would recommend even the overpriced wireless, that's how good of a time I have with it. I don't listen to dubstep or super heavy music though, so I can't give you an opinion there if that's what you listen to. But anything less intense, I've enjoyed it. I haven't once felt like I wanted to send them back. They're very good for me personally.