LSI9's With PW650

two ways to hook up a sub...Line level (rca cable) and speaker level (using the speaker wire). When you hook up the the sub using speaker level method, your subwoofer amp is doing the following task:

It takes the signal comming in from the wire and filters the higher and lower frequencies ( based on the crossover setting you specify by turning the knob). Then the subwoofer amp amplifes the lower frequencies and sends the highs to the speakers...

(Note that the sub amp does not power the speakers hooked up to it. It only amplifies the lower frequencies. The amp [Usually a receiver] feeding the subwoofer amp is the amp that is powering the speakers and seeing the load, example 4 ohm, 8 ohm)

The line level works using the rca sub output or LFE output on the receiver and it plugs into the rca input on the subwoofer. S lot of new and some old receivers have adjustable crossovers built in. If not, then the crossover is fixed (usually 80Hz or 100Hz). Set your crossover (80Hz is generally a good place to start) on the receiver and then turn the crossover knob on the sub amp to its wide open position (max crossover setting). This will prevent what's known as double filtering, becasue you want the receiver to be acting as the crossover...

I consider the line level alternative to be the better of the two choices and it only requires one connection...

Hope this helps...
-BL