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.

Hi i am new to this,

so i want to buy a sonos amp s2 because i bought a pair of kef r3, 

so if i buy a sonos amp s2 and plug it onto my gpu rtx 3080 on hdmi i will get a lantency ?

that sounds wierd if you ask me, becuase if i plug a headphone on my monitor it is perfectly sync and it uses old dp 1.4… ofc i can use hdmi to but i choosed dp over hdmi,

unless the sonos amp is to slow with its hardware to run from a gpu for gaming and other media

1. if you’re planning on using the low latency digital HDMI connection, it works off of hDMI ARC, not standard HDMI, so you’ll need a device, normally a TV set and not a monitor, that contains the electronics necessary to create the HDMI ARC signal. There are a few devices out there that have that electriponocs outside of a TV, specifically the the HD Fury Arcana, the Feintech VAX04101k, and the latest, and least expensive, I think,  is the OREI HDA-935. Check your local retailers for availability, or Amazon. You can also order from those links from the companies directly, I think.
2. if you choose to instead use the analog (RCA jacj) input, Sonos will, in software, delay that input by at least 75 ms, in order to play it in sync across any grouped Sonos speakers. There is no way to get around that function, which is probably why Sonos does not advertise their system as a computer speaker system. 
    
3. Sonos does have an thread where they discuss those who choose to use Sonos in such a manner here. 

This is what I never understood.  No matter what input you’re using (HDMI ARC, RCA jack, etc) if you are not grouping speakers, why is a delay introduced?  I understand the delay to play in sync across grouped wireless speakers, but if you’re ONLY hard-lining bookshelf speakers to an AMP, or ONLY using Play5’s via 3.5mm (for people who wanted to use them as DJs or for live music) I don’t get why the 75mm is introduced since nothing needs to be synced wirelessly.

There is no ‘only’. The software always works the same way. 

It’s the way Sonos designed the system. They’re pretty careful never to advertise functionality as computer speakers, or suitability for DJ work, it’s not what the system was designed for. It’s like trying to force a Yugo car to plow a field. Can it be done? With contortions, probably, but a lot of potential issues will arise. Better to get a real tractor. 

Any one tried the https://www.paragonsns.com/products/pro-ject-optical-box-e-phono?variant=31468094390335#tab=overview

To eliminate analogue delay with Sonos?

Hi.  Could you explain how you are hoping it would help?  What is the use case you are thinking of using it for? This device seems to be aimed at use with a turntable, and I can’t see what problem it would solve in a Sonos context.

There will always be a lag when Sonos speakers are grouped.  This isn’t really an ‘analogue delay’, it is necessary to allow perfect sync across Sonos ‘rooms’.

Please clarify.  

If SONOS allowed a passthrough direct connection, and a user (somewhere in the site) decided to Group with the direct Room, there would be an interruption in that direct Room while the 75ms is inserted. I’m sure that this would introduce its own sort of ire.

In the SONOS vision, Line-In is simply a network resource regardless of where it plays. In this context the wired device is playing from the network, even in the connected box.

You can get an analog to digital convertors for under $20 on Amazon. Phono preamps are cheap as well.  That device only makes sense if you just like the name brand/packaging and actually have a need for preamp/convertor/switcher device.  Would this eliminate some delay?  Probably.  However, the box surely has some delay in it, and the amp still has some delay in it with digital sources.   It’s not going to be as good as a direct digital source.

And as pointed out, this does nothing for the delay in group rooms, and completely unnecessary if you are syncing to video or trying to use Sonos for DJ/PA  purposes.