Need help with line level highpass filter


2011-06-02 7:10 pm
I have an active subwoofer and two satellite speakers that I run off of a separate amp to make a 2.1 channel system. Both the sub-woofer and the satellites receive analogue line level input from my computer. I used splitter cables to send the signal to each. The subwoofer has a low pass filter on it, around 100hz (I think) but the satellites are running full range. I would like to put a high-pass filter on the satellites of also around 100HZ (the satellites are only 30RMS at 4 ohms).

From what I have read a line level high pass filter, before the amp, will be the cheapest way to accomplish this. I would aslo consider putting a capacitor on each of the satellites, or a series of caps, if they would work and they did not cost too much.

What should I do and how should I do it? :)

Please be specific.


I'm rather proud of these because of how cheap they were. They are a pair of Memphis car audio speakers (power reference, coaxial, 5.25"). I bought them for $10 each several years ago. Finally I built a couple of boxes for them from a piece of scrap particle board shelf wood that was already veneered.



2010-07-18 12:02 am | Passive Line-Level Crossover

Use the 2nd order high pass at the bottom of the page. You will have to know the input impedance of your amp that's driving the satellite speakers, but that is easy enough if you have an ohm meter.
Not a fan of using a simple cap in series with the speakers as that can actually cause an increase of low frequencies to the speakers in some cases because of the resonance of the cap and driver/box impedance at Fc causing a boost.