sennheiser pxc 550: 10 Things I Wish I'd Known Earlier

http://alexisvsfg540.bravesites.com/entries/general/enough-already-15-things-about-pxc-550-we-re-tired-of-hearing

There are two different types of headphones that block noise. Most people are familiar with active noise cancellation headphones which sample the ambient noise in the room and produce a canceling sound wave in