A subwoofer with speaker-level inputs is especially easy to connect to your older amplifier or receiver! To do so, just connect to the speaker outputs on the source unit using speaker wire and then to the matching inputs on the subwoofer. You can even power speakers from the amp or receiver at the same time.

Can I use two different subwoofers?

Yes. You can run two different subs. Its optimal to run two of the same because in your case, the weaker sub may reach its limits before the stronger one.