Thanks for all your response guys
Actually I own an M50 but I feel that the bass is not that much in quantity (needs an extra amp to satisfy my hunger :P)
and ya I agree with Darknecron that M50 is good with the kind of string instruments like violin n guitars..
I also agree with xkonfuzed in terms of M50 got a bright and harsh treble..sometimes it fatigues my ear for a high pitch vocalist listening to. smoother one is a good preference..
Then, is this S500 character similar to AKG K420? since u mentioned about a tight bass n smooth treble..
I haven't heard the K240's unfortunately.