Roku did it, wireless dedicated 5.1

Certainly appears so. Makes one wonder if Sonos has already balanced the Arc/Beam as a center speaker to match with either the Ones or Fives, or if they’d need to come out with some other speakers in order to do this. 

It’s long been on my wishlist for this kind of thing to be undertaken by Sonos. I like my Arcs, but I’d love three actually separate speakers up front. 

I'm thinking since roku controls the video playback too, the delay everything so you have a nice big buffer to help keep everything in sync. Sonos does not have that luxary.

I am assuming the roku speakers only work with roku as the source, at least for this feature. 

That’s an excellent point. Life is ultimately easier when you have complete control from soup to nuts.

Sonos is somewhat hampered by only having access to the audio stream, coming from the ARC on the TV set. So they’re relying on several other things to occur before they get the data.