hi everyone.. heres the situation i want to make a low pass filer for the subwoofer i am making basically at the moment i am running the equivalent of a positive and negative rail into a speaker (driver) but for left and right channels from the audio output of my hifi will this be sufficient with the lowpass or will i ned an amplifier as well i think the formula for the pass is f=1/2piR or something similar !?!? i tried looking it up but im confused i want a frequency of about 40-60hz (is this right) anyone here in a good mood and feel like helping with the resistor and capacitor values !!! and maybe help with a very simple amp construction sorry if the above is a little unclear. many thanks!