I have a 5.1 surround sound card in my computer, a Sony MHC-GX40 Shelf System, and a Custom subwoofer with a Adire Shiva in a 7ish cubic foot enclosure ported and tuned to some subsonic frequency (the chart stopped at 20 hz, i think it's in the 15ish hz area) and powered by a CVT-300S from Apex Jr. I've had the 300S and shiva for awhile now, I origionally got the GX40 for christmas in 2002 i think, and it was about 1 year after i got it i became tired of hearing the whimpy 5" subwoofer. So i bought the shiva and MDF with my own money and my dad paid for the amp as a birthday present and we assembled it and put it in my room. I hardwired the sub to an extent by shorting the subwoofer activaion switch terminals, running a RCA to bare wire adapter out of the subwoofer jack, ran 18 gauge wire around my room to the high-level inputs on the amp, then more 18 gauge from the same line in (to bypass crossover) to a male RCA jack to a coupler and into the wiring on the 5" sub. Now i have a new SoundBlaster Live 5.1 surround sound card,and i want to connect it to the sub. One problem: the computer emits a roughly 500mv signal, while the shelf system emits a 120 watt signal. So I already know i'm going to have 2 wires going to the sub. How can i wire the 2 signals into the amp? Can i run the computer signal into the left input and the system signal into the right input, or can i run the system input into the left input and the computer signal into the RCA jack, or do i need to put a double pole double throw switch inline for switching between signals?