Several of the SVS subs have 3 ports, and plugging 1-2 ports is a method of lowering the sub's extension. BUT, as 'sraber' pointed out, there's a switch or knob on both the HSU and SVS that needs to be switched along with the insertion of the port plugs, which I did not realize. So now it seems apparent that something is being changed internally with the amp/electronics, along with the port plugs in these other subs-- a feature (switch) which is not available on the LFM-1.

So the big question is will I miss the 15-24 Hz range some of these other subs deliver?? I love the idea of 2 solid stereo Outlaw subs under $1K with free shipping now (with a couple of purchased cables). But will I wish I had that "wow" factor below 25 Hz in the HT???