I purchased some anthony gallo speakers back in November. I had just moved into a new house so I've been very busy and haven't even tried to connect the speakers until yesterday. I am curious how you had the subwoofer connected to your stereo system. I have a Harmon Kardon avr-430 receiver and I have tried to connect it using RCA from the subwoofer out of the receiver to the line-in. I am getting very disturbing results: loud popping, crackling, or little sound at all. The mps subwoofer has R/L inputs.

The manual states:
If you have a relatively new digital receiver it will have an "LFE" or "subwoofer" output. Usually this is a single RCA type jack. Basically you will be running a cable that has RCA connectors on both ends from this output on the receiver to the Line In jack on the sub. You can connect to either right or left input on the sub with the same results.