You plug the second set of preamp outs to the Audio Control input and select the invert option. Then hook up to both positive sides of the amp with the speaker wire. The invert converts one side to (+) and the other side to (-)...volia the amp is bridged mono into one speaker. Namely a subwoofer.
Also tried this with the 400x7 by bridging two channels the one sub and using another two for the main speakers. Long story short, with everything pulling off of one dedicated socket I was able to pull 17 amps for a short period of time. Didnt go any longer for fear of breaking a sub, but let me just say 17amps will make everything and I mean everything in the house shake. The port on that sub was blowing massive air.
Next experiment is to try both subs with the 400x7 with two chennels running to each sub and two more running to the mains.
Also another neat option is the Warble Tone Generator that uses a microphone and has a dial that goes from 125HZ down to 22.5HZ. Its a great way to see just how low you speaker will go before they lose all effiency and quit producing sound. Down to 31.5Hz everythin works real well but as I lower from there to 22.5Hz you cant hear or feel much of anything.
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