The speaker level inputs on your sub should have very high input impedance and will not draw power from the amp OR effect it's ability to drive low impedance loads.
You could, if you wanted to run the mains full range, just wire them as normal and a 2nd set of speaker wire...and it could even be magnet wire, to the inputs on the sub.
You'd know if you were loading your amp to 2 ohms or less. It'd get real hot, pretty quickly and/or simply would not be able to play very loudly.
Speakers ONLY draw what power they need, to the electrical limits of the amp. Power 'ratings' on speakers? Sort of a weird science thing. Better watts....are better.
Adjust the phase knob after getting the main speakers running and at maximum perceived bass. Just swap +- lead on ONE speaker and if bass disappears / diminishes put it back and forget it. Than add the sub to the equation, adjusting the phase knob until you get max bass again. It's lowest level should be 180 degrees from the maximum level.
If you are dealing with a HT receiver, you are doing something wrong in the 'setup' menu. Set speakers to 'large' or 'small'.....that sort of thing. I'm not an HT guy.
You could, if you wanted to run the mains full range, just wire them as normal and a 2nd set of speaker wire...and it could even be magnet wire, to the inputs on the sub.
You'd know if you were loading your amp to 2 ohms or less. It'd get real hot, pretty quickly and/or simply would not be able to play very loudly.
Speakers ONLY draw what power they need, to the electrical limits of the amp. Power 'ratings' on speakers? Sort of a weird science thing. Better watts....are better.
Adjust the phase knob after getting the main speakers running and at maximum perceived bass. Just swap +- lead on ONE speaker and if bass disappears / diminishes put it back and forget it. Than add the sub to the equation, adjusting the phase knob until you get max bass again. It's lowest level should be 180 degrees from the maximum level.
If you are dealing with a HT receiver, you are doing something wrong in the 'setup' menu. Set speakers to 'large' or 'small'.....that sort of thing. I'm not an HT guy.