I'm looking for the best way to set up 4 separate rooms (2 passive in ceiling speakers each) that I can separately control with my iphone/ipad. Sonos is great but expensive. My idea was to have 4 separate airport expresses (one per room which is how I would control each room independently) and pair with a multizone amp. Would that work? The airport expresses would always be in powered up so, if I selected one to play music in a room, would that turn on the amp or is that always on too? Would I be able to control volume from my iphone? If the airport express idea wouldn't work, would a sonos solution solve the problem? Sorry if this is naive, but I don't know much about these kind of setups.