To add to that, I just use a Fiio E6 to boost the bass on my M50's and they seem to be quite punchy although they don't have the QUANTITY of bass that the XB500's have. I'm just using RPG's preconfigured EQ for foobar for the XB500 with no amp and they still have a ton of bass, but like he said...

I've owned the M50's for a while now and the XB500's for about a day. I thought I was a basshead, but man, these XB500's have a LOT of emphasis on the bass. If I had to choose between the two I'd go with the M50's just for the better SQ. Not that the XB500's aren't a fun listen. The M50's are...