I’m considering the same setup. Did anyone figure this out?  Thanks!

No responses, so I’ll take a whack at this.

Since the Onkyo is advertised as “works with Sonos, you’ll need to be using either a Sonos CONNECT or Sonos Port to connect to the Sonos ecosystem. If I read the information on Amazon correctly, that should allow use of the Sonos to cause the Onkyo to switch over to the Sonos input. Any amplifier with a line level input should be able to play a Sonos input from either the CONNECT or Port.

It’s important to note that the Sonos Amp doesn’t have an analog output, so it can’t be used to connect to the Onkyo receiver. However, if a CONNECT or Port are connected, then any Sonos device, including the Amp will be able to play any signal being sent to the Sonos ecosystem.

I’m not terribly familiar with the whole “works with Sonos” system, but I believe the system still works the same way as any other receiver connection. If you’re streaming from Sonos to the Sonos speakers and the receiver at the same time, all speakers will be in sync. However, if you’re using an input from the receiver (say a turntable or CD player, etc), then there will be a delay between the Sonos speakers and the receiver’s speakers.

If you have more specific questions, I’ll be happy to give you an answer to the best of my abilities, with the admission that I’m not a complete expert here.

I suppose it’s possible, and you’d need to read the Onkyo manual to confirm, that the Onkyo could delay it’s own speakers by the standard 75ms that it takes the Sonos to process the input from the receiver in order to present it in sync in all Sonos rooms.

Any experts who can confirm?