Many users who state they are not getting enough bass from four B1s generally are set up improperly, even at preset 00. Preset 57 will add a bit more punch, although the high ends become more shrill, and preset 58 will almost double bass response BUT also punch the user into the red much faster as well as creating mic feedback havoc if the mic is connected into the mixer and not directly into the powerstand.
I feel some peoples set ups just aren't right still after all this time. I don't have a problem with 300 people and 1 L1 and 2 B1's. I don't have a problem with 1 L1 and 4 B1's with 600 people. Only gig I ever used 2 L1's and 4 B1's, was 800 people. Had plenty of headroom and plenty of bass. Guess I'll just be hoping they get it right one day.
I have used my standard powered speakers (Mackie SRM450 or JBL PRX512) with the Compacts. These speakers are Wedge style, which makes them great for floor subs.
My Denon X-500 Mixer has a sub output, which only feeds low ends to what ever its plugged into.
This is great if you don't want to invest in extra subs, and need the extra kick, and as a bonus, it a backup active speaker!). It's also good to have with the Model 1 along with the B1 subs. Gives the dance floor a fuller base sound.