Can you expand on how they’re ‘out of sync’? How are your speakers set up, which ‘room’ in the Sonos software are they in, which input are you trying to play?

For instance, any ‘grouped’ room with the Arc room you mention, while playing the input from the TV, will be slightly delayed, but when streaming music, the multiple rooms should be in sync. 

A general suggestion, barring extra data, might be to power down all speakers, then restart them, so that they communicate the timing between them….but that won’t change the above statement. 

No, unfortunately you can’t. 

When you group additional speakers to the home theatre setup, there will always be a slight delay (75ms) on the grouped room for tv audio. Music playback will however play in sync across both rooms.

@Dan071973,

When ‘grouping’ (not bonding) Sonos rooms for the playback of TV audio, there is a delay to the grouped rooms as @Mr. T mentions, but also note that there is a feature in the Sonos App to introduce an audio buffer for the TV audio on the HT room only (‘Settings/System/iArc Room Name]’) which is called ‘TV Dialog Sync’ - you could try increasing the buffer (move the slider control over to the right) and see if that brings all the players back into sync, but note that such audio adjustment may introduce lip-sync issues for the video on the TV screen.

I (very occasionally) use the feature for TV PCM stereo audio when listening to music from in-built TV Apps like Amazon Music, Deezer etc.