I olny said 200 hz cos thats what this subs cut off was when it was hooked up to its ordignal inbuilt amp.
the amp is a old JVC A-K100 this system im just putting togeather for the shed for now with a couple old JVC 2 way speakers hooked up to a diffrent amp than the sub.
Um do i want it before the amp? i was just gonna put the filter in the sub box amp goes to the filter and the filter to the speaker.