Here’s a 3 band tone control with subwoofer output circuit. Take note that the main output are full range. This is not a 2.1 crossover circuit. It is powered with single power supply so you can use a battery or a simple ac/dc power supply.
This circuit is not yet tested. But it is based on an existing working design, I only modified it to work on single supply. I also connected the subwoofer line into the output of the tone control so it will also be affected by the bass adjustments. The original circuit has it connected to the output of the buffer, so any adjustment on the bass will not affect the sound of the sub woofer.
I also have not yet designed a PCB of it. I might design it when I have time so subscribe to my youtube channel and like my facebook page so you get updated. 🙂