ive a portapro n i love it now im thinking of getting a portable closed headphone n im eyeing the sennheiser px200.i listen to metal n i love the bass on my portapro is the bass of px200 good?i want isolation so that peoples sitting next to me wont be hearing my music, n so i dont have to on my volume loud so does the px200 do a good job at that?is the px200 as loud as the portapro?or should i just stick to my portapro?