im currently using 448, and i had own it more then 1year...
say reli, 448 is abit light of bass, but tat mid & high sound very clarity, for my experience i feel 448 sound more clarity better then 555...tis headphone are suitable to listen jazz/ classic music/ news age/ rock..... for a bass head owner sure no satisfied tis product or listen music of electronic / fast song are not suitable too~

if wanted an natural headphone go ahead HD5XX series(it more specifier for all range) or natural bass Brand or Denon D2000

every different headphone/ brand gt provide different sound stage..