Sonos Port for Multi-Room TV Audio

You could use the Port, provided the bookshelf speakers come with an ammo - since you are already using them I expect that is the case. If you haven’t got an amp yet the Sonos Amp would be good.

When playing TV sound there’s a 75ms lag between soundbar and grouped speakers. This could bother you if you are sensitive to it, but this sensitivity is very personal. I regularly group my TV with the Sonos One in the open plan kitchen some 10 meters away and am not bothered by the delay.

This is a long answer to your question, as a bit of history may help you understand the challenge in what you’re asking…

To achieve synchronised multiroom music play, which was how Sonos started the business, they used a 70msec delay when you start audio playing. This buffer enables dropped data packets to be resent to maintain continuous music play. Since there’s nothing to compare it to, the delay doesn’t matter when playing audio. 

When Sonos first introduced a soundbar, they minimised the delay for audio from a tv source to the soundbar, so there wouldn’t be lip sync issues. But, the longer delay still applies for audio sent to grouped rooms - whether that’s other Sonos speakers such as the Eras, or Amp-and-passive-speakers, or Port and other systems. 

I often group my tv speaker system with kitchen speakers so I can still hear the tv audio whilst in the different room. The audio delay is not a problem as I can’t see the tv so I don’t experience the lip sync issues. There is a small zone where I can hear the soundbar audio and the kitchen audio together, and that sounds like a slight echo as they are out of sync, but it’s only in that small zone where both speaker sets are equally loud. 
 

Some folk on these forums have set up systems and said the audio is fine in these kinds of setups; others have found it unacceptable. 

Does that help answer your question? Basically, you can’t have multi-room tv audio in sync for the reason above. 

Thank you both for the guidance! The history is helpful. So confirmed there will be some lag, but it sounds like hopefully the lag will be tolerable. I’m going to try it out and see if it bothers me. I’ll report back with the conclusion!

Update on this: I got the Port and am using it, and the latency between the soundbar and speakers connected via the port is negligible. It’s not perfectly in sync, but it’s not dramatic enough to cause an echo. Much better than playing audio through the 2 TVs and their respective audio outputs. Thank you for the guidance!