All this really depends on how well the bass management is within system. I agree most with set to what sounds best though some will disagree. You will have different results from different sources such as dvd or cd. The mains are sufficient for most music as is therefore full signal/large setting would be appropriate in this case however when watching a movie things change. I would say that your mains will handle the full load of the main channel soundtrack but certainly not the LFE track which is entirely independent of the other discrete channels on any given dvd/br. Therefore to say that setting at large is not a good idea is a bit premature. The lfe will never make it to the mains or any other spkr for that matter. It can only be sent by cable to a dedicated sub...powered or not. One advantage of setting spkrs to small is to relieve amp stress by having to work hard to maintain high levels. Sending some of the lower freq's to a sub takes the pressure off the amp to run hard. But, I have founf that depending on the sub this will not sound good in all situations. I know that I could not live with my spkrs cutting off at or about 100hz and the sub taking over from there down. So back to point...whatever sounds better, what suits your needs, and how much flexibility/adjustment do you have with the bm in the first place.
