Joe, I looked at the Dahlquist site, and yes, they do claim only 40hz for the QX125S. Unusual for sub makers, this may be conservative. If it gives you what you're looking for, fine, but I note that the Audioshop site shows that Marc has an attractive $650Cdn sale on the Axiom EP350. Marc also sells the QX125S at a similar price. I would think that for the money the EP350 would give you more bass extension, but you might ask Marc for his opinion. On this board Chesseroo has reported good results with running his M60s full-range and supplementing the lowest bass below 50hz with his EP350.
It's common to use the auto on/off feature on subs unless it causes problems with premature shutoffs, so it should be left on "auto" or whatever Dahlquist calls it.
