"By far the most common use is to deliver the LFE (low frequency effects) or .1 of a 5.1 sound system. Bass management in your amp/processor/receiver allows deep bass from the other channels to also be routed to the sub, as well as the dedicated LFE effect, which is useful if you don't have main speakers that can go deep. But the main reason to have a sub is to hear those LFE specific bass effects. They aren't routed to any other speaker." When you set an amp/receiver to no sub and have the other speakers to large, then the receiver sends the .1 info to the large speakers doesn´t it? If you have very large speakers all around then there is no need for a subwoofer?