You can "daisy chain" your subs:

receiver to line-in on sub 1, then line-out on sub1 to line-in on sub 2.

or you can get a splitter or y-cable and split it at the receiver, makes no difference.

According to Dr. Toole placing subs centered on opposite walls is best to flatten out the frequency in all seats, that may not be possible for all users. Do you think you need a second sub?

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