how do u know if a headphone is loud enough or not, and how good d bass is??

sennheiser hd215!! what do u guys think about it?? i badly want it!! thanks alot guys!!  

hey thank u fr replying to my last post. . :) bt since i live in dubai. . options are a bit low. . and costly. . what i have in mind ryt nw is d akg k514. . is it any good?? it looks like it is made out of cheap plastic. .  thank u again. . :)

  hey im new to the headphone world and ended up buying d skullcrusher. . d sound quality nd d loudness is a bit low for my taste. . can i use an amp fr it nd increase d sound quality??? thanks alot fr d help. .

hey m new to the headphone world nd dont know much about it. .  Razer Orca and d Grado sr60i are two headphones that i really liked bt am confused which one to go for. . which do u believe is better?? nd do u ppl think der r any other better headphones under $100. .  oh n i mainly listen to...