First off, I am not in the habit of reviewing headphones but these headphones are worth thrice more than what I paid for. I like to listen to good audio i.e. I have separates as my main audio system and value good sound. The headphones I have are the JBL Synchros S500, Sennheiser Momentum 2 Over ear, Samson SR850 (modded), Sennheiser HD598 (now with my brother). 
 
I am running this with the Fiio X5 1st Gen and I listen to all FLAC files and let me tell you that this combo will be my main listening combo for a long time to come. The X5 has no problems driving these 32Ohms cans. I find these headphones to be open sounding than most closed headphones. The SQ did tend to get better with use. The bass response seemed to get more accurate over time. About the bass, it's tight as hell and doesn't seem to linger thus very quick. I listen to a variety of music from The Beatles to Dire Straits to Diana Krall and the vocals are superb and accurate. The treble is smooth and not at all harsh. The treble is there and I believe in the advertised frequency response. While listening to Jazz or Classical, there is exceptional clarity to instruments. Nothing sounds muffled or subdued. I think this is also in large part due to the source i.e. the X5. 
 
I am not one of those to claim that I am hearing things I didn't hear before   but what I hear out of these cans is crystal clear and extremely satisfactory. I HATE the design of these cans and will change i.e. add some white element to it but in the meantime, this will be my last headphone purchase for some time to come.