Can you elaborate on why?  

excellent thank you, nice to see an "isolation" rating for each IEM.

Hey gang,   New member here and just finished reading the guide at http://www.head-fi.org/a/basic-guide-to-in-ear-canalphones   I've owned the Sennheiser CX300-B headphones for a good 5-6 years now. For the money i feel they've been a great set of headphones. But as time has gone on the...