It's a mechanical filter, not electrical. Maybe you should look into Knowles or Sonion as they have white papers or product information on the filters that come with BA drivers. They actually rate the filters by impedance values, and they are not electrical filters that filters electrical power. Obviously, looking at the graphs that were posted here, they block the strength of the acoustical vibration more so at certain frequencies and less so at others. Just look at the graphs and notice their affects. I assume they are more in lines with what we call "dampers."
Edited by SilverEars - 7/2/14 at 6:02am