You need to describe more about your system. The SW out from what? Is that device configured to output a SW signal and/or is there an LFE on the source? Does the sub turn on?

The simplest, and IMO the best, connection is to simply run some speaker wire from the terminals of the speakers to the speaker-level inputs of the subwoofer.

It can be lightweight wire, 18 or 20 gauge, because the current from speaker terminals to subwoofer will be very very small.

This ensures that the subwoofer gets the exact same signal as the main speakers, and is also independent of any setting on the amplifier or receiver.

For most speakers you can set the low-pass control of the subwoofer to around 60 Hz. You can experiment with that setting to see which gives the best overall sound.

If you do not have the user manual, you can go to the Paradigm website and look at Downloads in the PDR3 page and download and print it.

Please say what main speakers you are using and what amplifier or receiver is being used; that will help.

"Is that device configured to output a SW signal and/or is there an LFE on the source?"

In order to get a signal from the SW output, it is necessary to set the AVR's bass management which will reroute low frequency main channel signals to the SW out or to use a source with a .1 (LFE) signal.

Now, I've lost track of what we were talking about!!