Things aren't always what they seem. I will assume that you are running one PV900 in stereo to your SP2G's. If that is the case the SP2G is rated at 8 ohms, and at 8 ohms the pv900 is only rated at 180 watts per side. I would run your SP2G's in parallel off from one side of the amp which will lower your resistance(ohms) to four. At four ohms the PV900 is rated at 300 watts per side. So your talking 180 watts per side @ eight ohms or 300 watts per side @ four ohms. As neither of these figures is exactly over powering ( with the speakers you are using your actually seriously under powered no matter which way you configure it. I'd be on the look out for clipping.) So you might as well run half the PV900 for your SP2G's and the other half run to a monitor. We will assume your monitor will be rated at eight ohms also so you are only running 180 watts to it, once again not exactly over powered for a monitor. perhaps in the future you can add a second monitor lowering your resistance to four on the monitor half of the amp also. you didn't mention which bottoms your using, but there again, if the bass cabinets are rated at eight ohms each and you are running the amp stereo your only getting 180 watts per side out of it. For the bottoms( If they are 8 ohm each) I would bridge the amp and once again run the two bottoms in parallel. The PV900 is rated at 900 Watts bridged at 4 ohms. which is almost three times higher than you get running it at 8 ohms stereo. In any case, you can use what you already have and perhaps even a little more effeciently than you have been. I hope I helped shine a little light for you as my fingers aren't used to working this hard
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