Airplay Speakers- Philips Fidelio SoundAvia

The Fidelio Avia can be used as part of a multiple speaker set up and you can either control it from your computer or use an iPhone or iPad with the Remote App which interfaces with iTunes on your computer. The Apple TV can also be used as part of the same multiple speaker setup, as can an Airport Express, which is cheaper. In fact that is the system I have. I usually run my iMac, Apple TV and the Fidelio at the same time.

From the iPhone you can both choose tracks or playlists and adjust the multiple speaker setup, the relative volumes etc.

The only thing which is slightly problematical with the Fidelio is that it shows up in the Multiple Speakers popup at the bottom right of the iTunes window on your computer but doesn't show up in the control dropdown. The trick is to select it from the popup so it is playing in single mode, then go to the dropdown and click the other speakers on. The iPhone interface for the multiple speakers is by contrast flawless and all Airplay speakers will show up equally. Once settings are made they will stick.

As far as I am aware you will not be able to stream from your computer to the multiple speakers outside of iTunes so that precludes Spotify or Pandora, however there are lots of radio stations within iTunes you will be able to stream.

No, it's only iTunes on a computer can stream to multiple speakers. You can however, use the remote app on an iPad/iPhone to stream from iTunes on a computer to multiple speakers.

You can't select multiple speakers from the iPad, regardless of what type they are.

The Apple TV can't stream to anything.