Controlling output power?

Hello, could be a stupid question to ask but i cant seem to find an answer anywhere.

Ok so i have 4 fane colossus 18xb's and i am powering them with a lexon sae 18, what i want to know is how do i control how much power the amp is giving to my fanes.

i have my mixer connected to a behringer ultradrive and from the ultradrive to the sae 18 amp. The sae 18 amp has its volume turned all the way up and the speakers are connected in series to this amp (2 on each output at 4ohm) and have a wattage rating of 1000watt rms each so basically 2000watts rms each channel right?

But the sae pcm 18 has a 3200W per channel output, so when the mixer is tuned up full (staying within the green) will i not be pushing 1000watts extra into each pair of speakers?

Hi, haven't posted here in a VERY long time, hope it's OK that I'm US.... Anyway, in my system I run the power amps wide open & adjust the balance between subsystems with the processor ( a Driverack, in my case). I'm not familiar with your brand of power amp; the US brands are always trying to keep up with European designs. Anyway, it seems to me that you might continue to run your power wide open, then dial back the subs on the Ultradrive until you're sure they won't over-excursion (only 7.5mm Xmax?), then balance the rest of the system according to the sub levels. You'll have plenty of headroom for dynamics. Your box design also matters. My sub drivers don't have a lot of Xmax (6.7mm), so I designed a PPSL box with a semi-large Vb for that driver & a high tuning. I get just enough extension for live SR with excursion control due to the tuning.