I'm making an assumption that the subwoofer output on the SA3 is not frequency adjustable, but you'd have to perform that activity on the subwoofer plate amplifier itself, just like the Cambridge Audio CXA60, 80, 61 and 81. Though, in my case, I intent to use the SA3 just as a pre-amplifier to connect to my power amplifier with the MiniDSP integrated in-between, like I'm using it now in my current setup. After all the years of banging my head with subwoofer integration, the MiniDSP 2x4 HD has been the most valuable product that I've integrated into my system.