so is like left and right sub woofer channels a joke because if each analog is outputting 20hz-20khz i want the speakers to handle down to about 60 and have two subs (one for left and one for right).
I don't understand you, but I can assure you I made no jokes.
Since you are looking to run subs in stereo: it's going to be an external crossover. The least expensive good one (the one I recommend for just this) is the Behringer Super-X ($79 at parts express).
If you were using your computer for volume control, you'd take a 1/8"-RCA stereo cable, attach RCA-XLR adapters on the end, and plug it into the R/L in on the Super-X. Then run left-high, left-low, right-high, and right-low into your amps. If I assume that your subs have integrated amps: you can run straight from the Super-X left-low and right-low to your subs.
Check to see if your amps / subs take XLR connections: if not, you'll have to convert back to RCA (worst case: 6 adapters).
If you want external volume control: you will have to insert a pre-amp in the mix between your computer and Super-X. The least expensive way *I* know is to get an old stereo receiver with Pre-outs (I user a Pioneer 9700SX).