A port is okay for bringing your HiFi setup within the Sonos eco-system and when playing music audio to both Sonos ‘rooms’ all should play in sync. However, if you are looking to play the Arc/TV audio to the grouped ‘Port’ room, then you will experience a delay of approx 75ms, which will cause an ’echo’ if your HiFi is in the same room and note the TV audio delivered is just stereo only. I personally would choose to add a ‘Port’ for the HiFi setup despite the mentioned limitations, but perhaps then go onto add a Sub to the Arc ‘room’ (and two Sonos One/SL surrounds too) for both TV and Music audio.

Thanks Ken,

The TV and Arc and HiFi are in the same room..  Is the 75ms delay you mention due to the Arc connecting to the Port via the WiFi?  (I ask as I didn’t previously get a delay when the TV was connected via optic out to a DAC which connected to the HiFi via 5m RCA copper cables.)

If so, will I get a similar delay when the Arc is connected to a sub? (And does the Arc connect to subs other than those from SONOS, pse?)

The delay is needed for buffering when “grouping” “rooms”. When Sonos devices are part of the same “room” in Sonos you do not get the delay - so a Sub will be fine. You only get the delay when “grouping” two rooms for TV sound. Since you cannot have an Arc and a Port in one “room” grouping is the only way to have an Arc and a Port play together, which will be fine for music from Sonos sources, but not for TV.

The Arc connected to a SUB is a different ‘kettle of fish’ - those two devices are not ‘grouped’ together, but ‘bond’ together instead (directly) over a 5Ghz ad-hoc wireless connection and that connection is fast, so there’s no noticeable audio delay and the same happens with the two HT surrounds aswell, but when things are ‘grouped’ together that happens over a 2.4Ghz WiFi or ‘wired’ 10/100 network connection. 

The reason a 2.4Ghz WiFi is used is because it penetrates through walls much better and has a longer reach and so is ideal for grouped rooms around a Home - but it’s slower and so a minimum of 75ms buffer delay is introduced ‘by design’ to help cope with network conditions. In fact when sending some types of ‘demanding’ audio, such as line-in or TV audio, the audio buffer can be increased to as much as 2 full seconds to help cope with ‘stubborn’ network conditions. It also allows for the grouping of up-to 32 sonos rooms. (I tend to personally group just 6 sonos rooms myself).

Anyhow there’s currently no way to get around the delay in the Sonos eco-system, but one interesting fact is most modern Sonos speakers can now connect over the 5Ghz band, so as WiFi improves in our Homes maybe one day the TV audio delay will be less between grouped players and all will play the TV audio in sync, just like we see now with music audio on Sonos.