Quote Originally Posted by Hyfi View Post
Mark, I know this is how it has to be done with older setups but does it not negate the quality of the original amp or receiver since all the amplification is now being done via the sub's plate amp?
No,the crossover/summing circuit/amp circuitry in the sub strips off only the bass and the rest of the signal is passed through the sub virtually untouched, aside from the bass being stripped off. The crossover/summing circuit in the sub is essentially a passive device consisting of a few resistors.

IOW, the mains still see the product of the original receiver's amp and only the subwoofer driver sees the product of it's internal amp, which is what you want. On a deeper level, the receivers amp "sees" a very high impedance at the subwoofer frequencies so the sub has virtually no load (ergo, no affect) on it while passing everything else through.