Sonos Amp audio delay pre-purchase questions

  • 19 September 2022
  • 5 replies

My computer is my main entertainment hub, my large monitor is basically also my TV.  I want to get a pair of nice bookshelf speakers and I’m looking at the KEF LS50 Meta’s.


I’ve narrowed my amp choices to the Sonos AMP ($700, 125w), the NAD C700 ($1,600, 80w), or the Denon PMA-150H ($1,000, 70w).


I’d prefer the AMP because not only is it the cheapest, it’s also the most powerful.  I’ve done a fair bit of searching prior to posting.  I know using an AMP with a computer “is not the intended purpose” but beyond that I’m curious about the delay.


I understand that when GROUPED, the minimum delay is 75ms, which can cause lip sync issues.  However, in my use case, I would just be using wired bookshelf speakers, UNGROUPED, with the optical out of the computer to the optical to HDMI converter into the AMP.  From this thread, buzz said:

When SONOS players are “Grouped” there is a 75ms latency. The latency is reduced to about 30ms for the TV connected to PLAYBAR/BEAM/ARC/RAY/PLAYBASE/AMP.


My question is to users of the AMP.  In this situation, is the latency reduced to 30ms automatically?  Does the app still say 75ms is the lowest or does a new 30ms option populate?

Secondary question:

I only have a BEAM at the moment so I’ve never grouped anything with Sonos.  I see Sonos is releasing their new Mini Sub soon and it looks interesting.  If I purchased one of these and GROUPED it with the bookshelf speakers I understand the latency would raise to 75ms.  Can you easily GROUP and UNGROUP, changing the latency automatically?  It would be nice to have a sub, GROUP it when listening to music, then ungroup it when in media mode, but that’s only if the minimal latency is automatically adjusted back down when ungrouped.  Does anyone know if it would work like this?  If not KEF also has a nice small wired sub, but it’s almost triple the price of the Mini Sub.


Thank You.


Best answer by Ken_Griffiths 19 September 2022, 02:21

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If the connection to the Amp (room) is either via optical (using the Sonos adapter, sold separately) or an HDMI-ARC connection, you should not see any audio delay in the output to the connected chosen (KEF) passive speakers. If you also ‘bond’ a sub-mini to either that Amp, and/or the Beam, there will be no delay between the chosen master player when outputting audio to the connected sub-mini.

Where you will encounter a delay, is when playing A/V sources from the computer to the Amp/Sub (as an example) and also you decide to ‘group’ that Amp to the Beam (another Sonos room) - that grouped room (Beam) will be slightly out of sync with the Amp by 35-75ms and would likely cause an echo if they were both in the same room - but not noticeable if the Beam is perhaps in another physical room.

There are tools in the Sonos App to ‘buffer’ (delay) the audio on the Amp and ‘possibly’ bring both grouped rooms into sync, but then you may notice some slight lip-sync issues with the video on the monitor/screen. Note this only applies to A/V sources from the connected computer and the delay is only to the grouped room (Beam)… So, if you were to play music audio via the Sonos App, like Spotify, Amazon Music or Sonos Radio etc. (just as examples) the audio will play in perfect sync across all rooms/players (Amp/Sub-Mini and Beam).

If AMP’s input is via the HDMI ARC connection, you’ll have the short latency. Otherwise, the minimum latency will be 75ms. There is a video sync adjustment that can stretch the latency to better match other members of a Group when ARC’s input is from the HDMI.

Ah, thank you for the replies.  My confusion, I thought GROUPING was when you grouped wireless speakers together, like adding rear’s to a playbar or something.  Now I see GROUPING refers to grouping rooms together.


So, I thought if I added anything wireless to a setup, that would increase latency to at least 75ms, because the wireless allows for the buffer to sync up.  So if I understand correctly, if I’m using a AMP with the input HDMI ARC (optical out to Sonos Optical adapter) then I will get the lower latency even if I add a wireless sub?  Or will adding the wireless sub increase the latency to 75ms because it’s wireless?


Also buzz, is there a way to verify you’re getting the lower latency in the app, or will the 75ms be the only option you ever see in the app, and you just trust you’re getting the lower latency if the setup is configured via HDMI ARC?

Everything in each “Room” is time aligned. Grouped Rooms are time aligned with each other. Once you “Bond” units as a pair or as a  Surround Room, operationally, you’ll not be aware of the individual units, only their Room.

Sub & Surrounds all ‘bond’ and play in perfect sync with their HT ‘master’ player - collectively they become one Sonos room. If that ‘room’ is connected via the master to a TV HDMI-ARC or an Optical connection it will ‘usually’ play in lip-sync with the video on that TV. 

If that ’room’ is grouped with another Sonos ‘room’ the audio from the TV is sent in stereo to that grouped room and the buffering used in that group playback means there is a delayed output in the grouped room only of up-to 75ms which may cause an echo effect, when in the same physical room.

However there are tools/features in the Sonos App to help deal with the player sync, as mentioned earlier. The sync issue only applies to A/V audio - all music sources from the Sonos App will play in sync across all players, whether they are ‘bonded’ or ‘grouped’ together.