I'm looking for some advice. Today, the second zone of my receiver in my theater room also handles two speakers (background music) for the downstairs area of my house via a Squeezebox. The two speakers are in-ceiling and a volume control is also installed, but rarely used due to the phone and tablet interfaces.
Now I am looking to expand by adding two more in-ceiling speakers, bringing the total to 4. The receiver on its own is maxed out for speaker connections, so hence the advice.
Optimally, I would like to be able to have control over the two different pairs of in-ceiling speakers separately (one will be upstairs and one downstairs), or when necessary have them be in-sync. I know this can be achieved by purchasing another Squeezebox (or whatever they are called now), however, I don't know what my best option for connecting the speakers are. What do I really need here? An amplifier, a stereo receiver, something else?
Any help would be appreciated. Thank you.