Question

Receiver Line Out to Connect Amp Line In - Input Lag Question

  • 8 September 2017
  • 13 replies
  • 830 views

Hello, I'm considering adding a connect amp to our home. I currently have a 7.1 setup and am considering integrating the connect amp to the set-up. My thought is to connect the surround back L and R line-out to the line-in of the connect amp.

That way I can play music, where the receiver is, and not have to turn on the receiver. Also, whenever I watch TV with 7.1, I can still get the rear L and R channels to play through Sonos and also continue to listen to the show/event throughout the house.

What I'd like to know is if the audio lag is noticeable in this setup? I understand there would be a need to encode/decode the line-in signal to sync to other Sonos machines in the home, but was wondering if that has improved over the years via software, and the fact that there are other product offerings that are intended to work with a TV - like the play base.

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13 replies

Userlevel 7
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Interesting idea. I believe (from other postings on this forum) that the encoding delay is ~70ms. I'm not really qualified to comment on whether that would be noticeable, but I doubt it. (My understanding is that delays start to become noticeable at about 200ms).

The one part that doesn't quite add up is the 'listening to the show/event throughout the house'. You'll only be getting the rear L/R channels through Sonos -- that won't sound good.
Userlevel 4
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The delay will likely cause an undesirable echo. I wouldn't recommend this set-up.

You would be better using the Connect product and putting it into one of the sources on your AV receiver. Then you can play music through your 7.1 set-up as required.
Userlevel 7
Badge +20
The delay will likely cause an undesirable echo. I wouldn't recommend this set-up.

You would be better using the Connect product and putting it into one of the sources on your AV receiver. Then you can play music through your 7.1 set-up as required.


That's definitely a better idea, and it's what most people (including me) do. It's also cheaper, since you need a CONNECT, not a CONNECT: AMP.

I was just intrigued by the concept.
Userlevel 4
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yes, I have the same set-up - although I've never actually used it since I plugged it in!
I have nothing to add to the guidance already offered, but would like to correct one misconception in the original post. The delay is not an encoding delay that needs to be improved by software updates. It is deliberate and necessary in order to allow multiroom synchronisation when playing music, which is what the Connect and Connect:Amp are designed for.
Userlevel 4
Badge +2
I have nothing to add to the guidance already offered, but would like to correct one misconception in the original post. The delay is not an encoding delay that needs to be improved by software updates. It is deliberate and necessary in order to allow multiroom synchronisation when playing music, which is what the Connect and Connect:Amp are designed for.

Actually, it is an encoding delay - which is also why it varies depending on whether you choose compressed or uncompressed line-in. Choosing to compress delays it further.

The delay is caused when converting the analog input signal to digital. On a digital source, like with PLAYBAR, there is no need to convert and therefore no delay. You can still send your TV audio around the house in sync, there still isn't a delay.
You can still send your TV audio around the house in sync, there still isn't a delay.That is not correct. The Playbar will sync perfectly with grouped speakers for music sources but not for TV (as I have just re-proved to myself by listening to a rather echoey Play:5 placed next to my Playbar). There is delay deliberately built into the Sonos system to allow multiroom sync. In the case of the Playbar, the priority is lip sync, and the Playbar typically lags the video by 30ms, which is pretty unnoticeable. But the audio simply cannot get out to the other grouped speakers fast enough over 2.4GHz to stay in sync.
Incidentally that is why bonded surround speakers communicate with the Playbar over 5GHz, which has much lower latency.

Clearly, encoding takes more than 0ms, but my point is that latency is fundamental to Sonos and the buffering is planned, not a flaw to be corrected.
Userlevel 7
Badge +20
Clearly, encoding takes more than 0ms, but my point is that latency is fundamental to Sonos and the buffering is planned, not a flaw to be corrected.

How long does encoding take, then?
Interesting idea. I believe (from other postings on this forum) that the encoding delay is ~70ms. I'm not really qualified to comment on whether that would be noticeable, but I doubt it. (My understanding is that delays start to become noticeable at about 200ms).

The one part that doesn't quite add up is the 'listening to the show/event throughout the house'. You'll only be getting the rear L/R channels through Sonos -- that won't sound good.


Ah, the listening to show/event throughout the house is a very secondary need. For example, going upstairs to get a snack while not really missing too much dialog if it's a live event. In that case, the receiver would be playing all channel stereo, in which case the other Sonos devices would play the stereo audio via the single speaker play 1, or two speakers on my connect.
The delay will likely cause an undesirable echo. I wouldn't recommend this set-up.

You would be better using the Connect product and putting it into one of the sources on your AV receiver. Then you can play music through your 7.1 set-up as required.


That's definitely a better idea, and it's what most people (including me) do. It's also cheaper, since you need a CONNECT, not a CONNECT: AMP.

I was just intrigued by the concept.


The connect is definitely the cleaner way to go . But, the benefit of the sonos amp is that its designed to be always on. What I'm trying to work around is the fact that the receiver needs to be turned on and switch to the sonos input. Not a big deal, but not as automatic as I would like.
Userlevel 7
Badge +20


The connect is definitely the cleaner way to go . But, the benefit of the sonos amp is that its designed to be always on. What I'm trying to work around is the fact that the receiver needs to be turned on and switch to the sonos input. Not a big deal, but not as automatic as I would like.


Good point. One does get used to the ease of spinning up music on Sonos speakers, and -- similarly -- the CONNECT: AMP.

I have an old (IR-only) Harmony One remote that I use with all the AV kit, which gets me most of the way to automation, but it's still a two-step process for the CONNECT.
Userlevel 7
Badge +20
My understanding is that delays start to become noticeable at about 200ms.

Btw, scrub that thing I said -- at least for lip sync issues. Seems they're subconsciously noticeable above 40ms lag and consciously noticeable above 90ms lag.

This white paper cites some Stanford research from 1993:
http://www.prosoundtraining.com/site/wp-content/uploads/2014/02/Lip-Sync-Errors.pdf
Clearly, encoding takes more than 0ms, but my point is that latency is fundamental to Sonos and the buffering is planned, not a flaw to be corrected.

How long does encoding take, then?

https://support.focusrite.com/hc/en-gb/articles/206674669-Does-analogue-to-digital-conversion-cause-latency-