I just received my new PC350's today in the mail and before that I was using HD555's for about 9 months or so. Clearly the 555's sound better than the 350's. I play cod4 so I can tell the difference atm. Is this due to the 350's being brand new out of the box today and needs to be worn in as my 555's have been or is it just because the 555's are superior to the 350's? I'm fairly dumbfounded when it comes to audio so any information is helpful. Thx