Filters vary somewhat but the one I measured was only 9 kHz wide. http://www.jlkolb.cts.com/site/curves/F455N801.PDF John At 05:35 PM 1/18/2010, Les Locklear wrote: >The only pertinent information I posted lately was the fact that the >8 kc mechanical filter was actually 11 kc that's why they sound good.