From some of the things I’ve read in the past, from a variety of threads on this and other forums, I think the HT audio-delay can and does (very slightly) vary, depending on the type/position of the surround and connection, but that it is somewhere between 5ms to less than 30ms, but that delay to the surround audio-out, includes the point at where the audio is first received by the main HT player.. which obviously is responsible for delivering/distributing the audio to its surrounds and sub.

You may see mentioned in threads here, that a 2.4Ghz WiFi signal isn’t quick enough to deliver the audio at that rate to a surround and that’s why the connection between the main player and surrounds/subs use the much quicker 5Ghz wireless band, or sometimes a fully wired setup, ideally with all connections back via the main player and/or to the same router switch.

I don’t know what the audio-mdelay is from a source, through the TV upto the point where it is received by the main Sonos HT device, but it appears to be in this area where most people seem to have audio-delay issues as the TV may not process the audio quickly enough in some cases out through its ports.

If the audio is from an external source, like a TV cable box, just as an example, and that audio is delayed by the TV, then some users have got around that issue by bypassing the TV altogether with an audio extractor/splitter device. That said, many (non budget) modern TV’s are now improving in this area and new generations of TV Processors (and other hardware) seem to be addressing many of the audio-delay issues of the past. 

Ken,

Thanks for your response!

Hmmm.  Well, if the range is 5-30 ms, I guess that’s what it is.  But it troubles me a little bit b/c it seems like the relevant experts seem to agree that 5 ms is acceptable, whereas 30 ms is maybe not…  Apparently the recommendation for film is <22 ms delay in either direction?

https://en.wikipedia.org/wiki/Audio-to-video_synchronization#Recommendations

Adam

I will just briefly re-state that the information I posted on the topic, comes only from the various sources I have seen folk mention. It’s not something I’ve tested/nor have the means to test personally,  but I guess to get the ‘real’ answer, you may have to contact/write to Sonos for that.

I assume however that Sonos are within the ‘given’ limits mentioned, as I have the Arc and two Beams, with Surrounds/Sub on three different TV’s here at home (2 x LG and 1 x Samsung TV) and the lip-sync from surround audio has not been an issue for the family/guests or myself. 

Lip-Sync issues seem to be related to some manufacturers TV models... I thought this link below was interesting as LG (just as one example of a reputable manufacturer) do state they are aware of lip-sync issues in general and explain why they have introduced tools on some of their TV models to try to address the issue.

https://www.lg.com/ca_en/support/product-help/CT20098005-1399374324873

The Sonos HT delay is around 30 ms. This is determined by the minimum buffering requirement to avoid dropouts in the HT satellites.

(The bandwidth/speed of 5GHz is not directly relevant, only its latency and the variation thereof. By choosing to use a dedicated direct 5GHz connection Sonos is able to steer clear of other traffic and interference. The latency therefore remains consistently low and the network buffer can be kept shallow.)

The Wiki article linked above in fact says “For television applications, the Advanced Television Systems Committee recommends that audio should lead video by no more than 15 milliseconds and audio should lag video by no more than 45 milliseconds.” On that basis the Sonos HT setup is within bounds.

It’s worth noting that for every additional foot you sit away from the speaker an extra 1 ms delay is incurred. So 10 feet = +10 ms.

Interesting to get to some specs on this - but in practical terms - assuming no Arc related hdmi nonsense causing sync issues, I can’t say I’ve noticed any ‘HT delay’ with delay of the various Sonos HT configurations I’ve had over the years. So whatever the ‘magic number’ is. Sonos seems to just work and all is well. 
 

PS: i appreciate this is by no means an answer to the question - but hopefully helps alleviate any concerns. I expect unless the viewing room is very large it should not be an issue at all. 

PPS: I consider myself very ‘sensitive’ to audio timing having had a mis spent youth matching loops at sample level on hardware Akai samplers. So I can tell the difference between 5ms and 10ms on a drum loop lol (just to qualify my other opinion) ha ha.