Just a couple questions about the Phoenix Gold Octane-R 15.0:1 (I think other octane series are set up the same also). Why does it have two speaker outputs when it is supposed to be a mono amp?? Is there any specific reason for this. Do I just bridge it as I would a normal two channel?? Also, I can't seem to figure out the gain on this amp. Previous amps I have had have clearly stated which control is the gain, but on this it just has Input Sensitivity, Crossover Frequency, Twin-T Bass EQ (Bass Boost), and Subsonic Frequency. Thanks.
Input sensitivit = gain. Subsonic = basically HPF (but in conjuction with a LPF to filter out normally frequencies below what your box is tuned to in the case of a ported box).
It has two outputs, to make it easier to hook more than one sub up, as class d mono is more efficient than AB etc, more and more people are using mono amps to power more than one sub.
You dont need to bridge this amp, picture both positive outputs as just a single output, just with an additional connection piece.