I haven't found that there's any real "tuning" to the filters. The response doesn’t' change that much by adjusting the caps on top or bottom, however the IL does change, but only a few dB by measurements I've made. I was suprised a bit by the difference in the IL of the 2 and 4 K filters compared to the 8 and 16, about 15 dB more IL for the 2 and 4.