Pierre Sprey from Mapleshade Audio recommends as follows:
For achieving seamless integration of the subwoofer sound in both two channel and surround systems, always use the speaker cable input on the sub, never the RCA line level input. That means adding a pair of speaker cables, one end connected to the same amp (or receiver) output posts that are driving the left and right mains and the other end connected to the left and right speaker-level inputs on the sub. The quality of the cables to the sub affects the sound of the main speaker cables, so don’t use bad-sounding zipcord or high end “garden hoses.” Make sure you leave the two main speakers connected directly to the main amp outputs, not to the subwoofer’s output binding posts. If you’re using a processor, set it to “Large Speaker” for the mains (or for all speakers) and turn off the LFE channel.
• Always fire the subwoofer driver left or right, not directly at you or down into the floor. If the subwoofer is off center, then test left-facing versus right-facing to see which sounds better. If your subwoofer is designed to fire down, set it on its side with the driver facing left or right. Be sure to rigidly mount it to the floor or platform as per the second bullet below. You’ll love the increase in bass articulation and clarity.
• By ear, set the crossover at the lowest possible frequency that doesn’t leave a bass “hole in the middle”. To do this, use as a test track one minute of a well-recorded bass solo that covers almost the entire range of the bass. Start with the crossover much too low so that there’s an obvious bass weakness somewhere in the middle or lower octaves of the solo. Nudge the crossover up 5 herz at a time until the bass weakness just barely disappears. Setting the crossover slightly too low sounds far better than setting it too high.
