Skerdi, the 804 doesn't use the common "large/small" terminology; instead it uses "full band" for sending all frequencies to that speaker, which is the same as setting it "large". If, on the other hand, you set a crossover frequency for that speaker(which rolls it off below that frequency and sends the sounds to the sub instead), this is the same as setting it "small". There's no separate crossover setting required for the sub because setting the crossover frequencies for the speakers automatically sends the frequencies below those settings to the sub. The most commonly suggested setting is 80Hz, since regardless of the bass capabilities of the speakers involved, 80Hz is a good compromise; it's high enough to take a substantial bass load off of the speakers but not so high as to make the sub easily localizable.
