HOW DO I SHOP FOR HEADPHONES?

in no about headphones so dontgive me basic desine ii no the best headphones are sennheiser, audio teachnica boss, etc. i alo like bass but i dont no how to get the right headphones.MDR-XB500 NC7/BLK CV 185 HD 20211 ??????! are the numbers and letters desins r what i no about mm diamiter like 40mm/ 50mm diamiter but thats about it i have skullcandy hush 50mm and the bass is soooo explosive its like boom lol but thats all it says i need to no the measurments of bass and what do thos # mean pls help