I have had my stereo subs set up in two ways: in both methods I have no crossover and the subs serve as bass augmentation. At first I had my speaker wire running from the amp through the speaker level inputs of two Dayton plate amps (left and right) which have their own binding posts that went to the subs. The speaker cable from the main amp then continued on to the main speakers. So it was kind of like a stop off at the speaker inputs of the plate amps. But without going through any of the crossover in the plate amp. (Blumenstein audio has an illustration of this method). The second method which is what I use now involves the output of my DAC which has both a preamp function and a line level output. I use the standard line level out to my main amp which has a volume control which drives my main speakers. Then I simply run the preamp out from the DAC using RCA to each plate amp which power the subs. The speakers run full range direct from the main amp. The subs are controlled by the preamp output. I suppose this is the same as bi amping but with a low pass filter in the plate amps rather than a crossover. I can control the level of bass using the preamp volume. And because I don’t change volume very often I can pretty much set and forget. Because I can separate left and right with the preamp and the two plate amps I can get true stereo bass augmentation.