Sonos Play 5 Gen 1 Line-in Delay with Connect S2

The “no delay once the Play:5 is taken completely offline” mentioned in that thread was indeed false.  The poster was either mistaken, or had some ulterior motive for claiming they were able to eliminate the delay.  There is no way of eliminating the minimum delay on a Sonos Line-In, and I suspect your observance that it is “noticeably less than 75ms” is either due to distance from the source, or some placebo effect. 

Also, it has nothing to do with any “smart” processing.  The Line-In inserts a buffer to facilitate streaming without errors.  All Sonos streaming has this buffer, but because the Line-In audio source arrives in real time, the buffer take 75ms to build up before streaming begins, whereas the stream from other sources arrives at the speed of the network, so the buffer is built up almost instantaneously. 

Appreciate the technical breakdown on the buffer.

However, I’m not claiming the delay is eliminated or arguing the exact 75ms/ADC math; I explicitly mentioned the delay is still present. My point is that the severity of the echo changed. Taking it offline moved the experience from 'unusable/driving me crazy' to 'functional as a group.'

I can definitely rule out the distance or placebo theory. My speaker placement was identical before and after taking the Play:5 offline; I didn't move an inch. If I can hear a distinct difference in the echo while sitting in the exact same spot, the change is real.

To be sure, I even played around with different volume combinations to see if I could 'catch' the echo or if it was just being masked.

The fact that the heavier delay actually returns from time to time - like when I skip a track or re-group the speakers - only confirms that I can tell the difference between the two states. It’s not a perfect science, but for my setup, the trick definitely does something that makes it tolerable.

Make sure that no additional Line-In delay has been inserted.

Sorry to be blunt, but I don’t agree.  The mind is easily fooled, especially when there is an emotional attachment to an expected outcome.  The delay is 75ms minimum.  If you are claiming to hear less than 75ms and are being truthful about that claim, then either you are mistaking a delta from >75ms to 75ms as a reduction to below 75ms, or you are experiencing a placebo effect. 

Either way, the original thread has been around for going on 4 years.  The effect the thread claims has been cited often, and there’s not been one instance where the results stated in the thread (delay removed entirely), or the results you have stated here (delay reduced significantly), have been independently observed.

ETA: Unless I’m missing something, that is.  If a Sonos rep wishes to correct my statement above and reveal that the delay can be lessened (<75ms) by disabling the networking on the unit, then I will give the largest mea culpa this forum has ever seen.  I don’t have much confidence in having to do any such thing, but you never know . . . 

I hear you on the 75ms floor - not trying to rewrite the laws of Sonos physics or claim it’s a pro-grade zero-latency monitor.

My point is strictly about functional utility for the price. 

Ultimately, this is a budget hack for people who want a bigger soundstage without the heavy price tag. Or even grab a Play:3 if you want peace of mind for the sync. I’d rather tell people, Play 5 is still a gem for its price and works well enough to save you £400.

Yeah there’s no additional delay inserted

I’m not trying to belabor the point, and I understand the moving of goalposts, but when you say “I hear you on the 75ms floor - not trying to rewrite the laws of Sonos physics”, you most certainly were disputing the 75ms floor when you stated in the OP “The delay is still present, but it's noticeably less than 75ms”.  If that claim has now been corrected, then we are in agreement; the delay is 75ms and cannot be averted. 

I’m not looking to get hung up on the 75ms figure - I only mention it because it’s the only reference point the S1 app gives me.

When the speaker was online, the echo was unusable. After taking it offline, the echo improved to the point where I could actually enjoy the music. I didn't move my seat, and I didn't move the speakers - the only change was the connection, and the improvement was repeatable.

I'm happy to leave the technical specs to the experts.

It is not possible to Group S2 and S1 systems together. If you connect them via a Line-In you’ll encounter the minimum 75ms offset. It’s not easy, but it is sometimes possible to simultaneously start the same online source or local library track on the S1 and S2 systems. Typically they will soon drift out of synchronization.

Or, for that matter, a Sonos system of any type and directly (app) streamed source. I frequently use both my Sonos system to listen to ball games via iHeart radio’s stream, and then go out on walks using iHeart app and Apple AirPods. I’ve never even tried to get them in sync. It’s painful for the few seconds both are playing, but I’ve learned to turn off the Sonos fairly quickly after the pre-roll ads on iHeart, so that I don’t get the echo part.

I also learned my lesson on streaming when I used to use my DirecTV streams, using two display devices, one in my bedroom, one in the living room. Even when watching the same channel, using one satellite dish, I couldn’t get the two receivers to sync up properly. And the same when using the iHeart app on my phone and iPad…never synced, even though both were the same stream. 

There’s a real reason why I depend on Sonos grouping to sync their own speakers. While I don’t tend to think about it as often as I should, it is an impressive engineering feat.