Most in-ear headphones offer pretty good passive noise isolation with just their silicone or foam tips. But sometimes, when you need to block out an even greater amount of ambient noise, you're going to want to invest in active noise cancellation. The PS 20 NC in-ear headphones with active noise-cancellation by Phiaton promise to block out up to 95% of external sounds you would prefer not to hear. Can they live up to this claim? Hit the jump to find out!