Hi Randy,
I built my LABs as a "C" rig to go under Mackie 1232's. The reality is one LAB sub will keep up with 2-1232's. This rig has become my favorite for quick strike/setup and having tons of headroom. Doesn't hurt there's a Midas 320 in the mix position.
As for the amps, I started with QSC PLX 3002's bridged mono, 1 per LAB cabinet (3000 watts per box,assumed 4 ohm load). This works really well as there seems to be limitless juice at the amp and the transients are really quick (high cone acceleration, good gamma factor) as the audiophiles would say. This box has some impedance swings and these amps handle them with ease.
There is a Dbx 260 riding herd at the front of all this. Use a good DSP if you power up this strongly. The amp has the 30 hz filter engaged as well as the clip preventer thingie (dip switch). Delay the tops 10 ms. Use 10 ga. wire between the amp and cab. Keep the wire 10' or shorter at this power level. 30 hurts! Yes, what a feeling of power, making buildings rattle at will with the 5 string bass.
In the mood for change (as usual for me) I switched these out for Crown Macro VZ-3600's one night. After getting the sensitivities matched on the front end I fired them up for a A-B test. W R O N G!!!!!!!!!!!!!!!!
The 12's bottomed out! No where near the cone control. They did sound a bit more aggressive (that VZ growl) but at high volume levels with kick drum impulses in the mix, they didn't keep the cones happy. This was with the VZ's run mono as well.
Interesting to note, bass guitar and CD's did not bottom them out. Only when I added kick did they protest and loose it. I think 5k's run stereo would be better suited for the application, but since this is a "C" rig and $$$$ matters, I can buy 2 PLX's for what I'd pay for ONE VZ-3600. I just had them sitting idle and wanted to try them that night.
As you may have guessed, the PLX's live happily in the amp rack now. Never more to roam or stray. Happy campers and only 22# each. My back loves it!
To each his own:
Your milage may vary,
Dan O