I've already posted a thread on the car audio, but I couldn't get my questions answered. I plan on making an active filter to filter a signal below 250 hz. for my front speakers. Someone suggested I use a passive filter, but I can't find the capcitance of the high pass on the two-way speaker. First question, will the opamp serve as a buffer between the RC circuits, meaning the highpass in the speaker and the Rc circuit before the opamp? Second question, I want a gain of one on the filter, so will I need to place a positive/negative DC signal on VCC & VEE of the opamp? I appreciate your assistance.