amps are described by their number of "channels"...if you have a "two channel" amp, you can run one set (two) of speakers. If you want to run 4 speakers, you need a four channel amp or two two channel amps, then an additional one channel amp for your...
That's tricky. Some of the OLD Lanzar amps are pretty good. When they were made by Zed Audio. The new ones are not as hot. If it is an "exploRe" amp... I have seen this. It is a rip off on a Sony Explode amp, and it is total garbage. If it is and Exp...
2-channel amps are designed for two speakers and 4-channel amps for 4 speakers. You can usually bridge a 2-channel to one and a 4-channel to two channels. This will half the impedance of whatever the speakers are.