Fascinating. I know the ones I wear work, but they were 'borrowed' from a server room, so might be somehow different... This blog talks about the 'filtering' y

Fascinating. I know the ones I wear work, but they were 'borrowed' from a server room, so might be somehow different... This blog talks about the 'filtering' you describe, completely new to me... http://eardefenders.org/2011/07/filtered-v-s-non-filtered/ http://eardefenders.org/2011/07/filtered-v-s-non-filtered/