I have HTC 8X equipped with beats audio system and also have Beats Mixr and Sol Republic headphones which ensures me GREAT audio experience. But thing is when I use any of those headphones on brothers Lumia 620 I get muddy bass, barely crisp sound which is also a lot weaker than on 8X.
So are there any headphones for Lumia devices that could give me nearly good experience as I have with 8X?
P.S. There is nothing wrong with Lumia 620.
Just like others are saying, Beats are not considered to be very good headphones. Most people go for them based on image. Sol Republic is a better choice in that case.
Anyway, back to your Lumia 620 problem, which is most likely based on compatibility. One option that is compatible and recommended for Lumia by the
experts I've found online is the LG HBS-700, and it's also very portable which is good with a phone on the go. Or if you want to be completely sure of what you are getting, just get the Monster Nokia Purity WH-920. Personally I use the Audio Technica M50x, but I have a HTC One M8, so I'm not sure if it's compatible with Lumia or not.