The speaker selector is what you need. It sounds like just a 4 pair selector will do. Something like this should be fine.
It’s not too much of a load for most all receivers. The only thing to look for is to make sure your amplifier/receiver will operate with an 8 ohm load. It might say something like use only 8 ohm speakers. If it mentions 4 ohm speakers it’s fine as well…the lower the number on a receiver/amp the better.
As for a single speaker in the bathroom, use a dual voice coil speaker like these. They take both a left and right feed and plays out of the single speaker.
> Name :
> Kevin Kellogg
> Message :
> Hi, I have a stereo system with just two speakers, I want to extend this to have a single speaker in the bathroom and two more speakers in the Kitchen. How is the best way to handle this addition? I have looked at the switches to select speakers, but how much is too much of a load? Also, in what manner do I hook up that single bathroom speaker?
> Thanks, Kevin Kellogg