Logitech X530 Subwoofer Mod - turn it into an active sub without the control speaker

How to convert your Logitech X530 subwoofer module into a separate active sub without needing the plug-in control speaker (the one with the volume knob and power button). You'll need, a Philips head screw driver and some modest soldering skills. Take about 30-45 minutes. Will accept phone input levels (say less than 100 mV), or small speaker levels as an input signal. I've also done a full frequency test (at 10 min 45 sec) - works down to about 15 Hz.