I am sorry but there is no Arc lip sync problem for Sonos to fix.  The Arc plays the sound when it receives it, and Sonos cannot play it any earlier than that.

I have installed an HDFury Arcana device on my system for other reasons (to get Dolby Atmos with my non-Atmos compatible TV) but now that audio is no longer being passed through my TV there is no lip sync issue.

Others on here may have other suggestions for Sky Q or TV settings you might try, in which case it may help to have the TV make and model.

So are you suggesting the lip sync issue is with my TV and therefore if I change my TV it will be resolved? 

I find that odd as I have read that the same issue exists with many different TV that people have used with Sonos Arc. 

My TV is Dolby Atmos compatible via the eARC HDMI we are using so to invest in the HDFury Arcana seems expensive for just lip sync which I shouldn't be getting having bought compatible TV and Sonos ARC. 

If anyone can advise further I have a philips ambilight 65oled754/12 connected via HDMI eARC to Sonos Arc. Input to TV is from the Sky Q 2tb UHD box. Thanks 

There are lots of TVs that output sound to external speakers with a lag, sometimes only with certain formats. 

Short of inventing time travel, Sonos cannot play the sound before it is received and has no control over the video element.

I hope you find a solution that is acceptable to you. There is no guarantee that buying a different TV would eliminate the problem so no, I am not suggesting that. I would not presume to suggest that even if it would fix it.

How is the HDFury able to resolve the issue then if Sonos cannot? Does that device then delay the image also so they are in sync? Or did they invent time travel and play the audio before the image? :) 

Apologies I don't know how the HDFury works.

Perhaps had I have spent money on a different soundbar I could have had Dolby Atmos sound without the need for additional equipment. I am sure you understand the frustration. 

I bought the Sonos Arc and a brand new Dolby compatible TV for the purpose of Dolby Atmos and so far I have not been able to enjoy that function. 

Philips TVs seem to be especially problematic in this regard. I have not seen anyone post details of any firmware updates from Philips, which is how TV manufacturers get fixes to customers. Have you checked for a TV firmware update, and if there isn’t one, contacted Philips?

The Sonos Arc is likely not the problem here, it can only play the audio when it receives it from the connected device (TV). Quite often, the TV is at the root of the issue in such cases. The HDFury Arcana can be used to bypass the TV, but note, this only works for peripherals like the Sky Q box and not the Apps built into the TV, usually the internal TV Apps may work fine and that too then points to problems with the audio passing-through/being processed via the TV HDMI ports. 
 

Some TV’s, like the LG C9, just as one example, have audio pass-through on the optical and Arc/eARC ports to help resolve such issues. Some TV’s also have A/V lip-sync features to further assist with these type of things.
 

So perhaps check your TV settings to see if there are similar features that may assist the audio to pass-through in a more timely manner. I would definitely ensure keeping the TV firmware updated as sometimes such updates can help to sort the matter.

It is on the latest firmware but I will be contacting them also to raise their awareness of this issue. 

I am still a little confused as to where the lag is. 

So the Sky Q sends video & audio together from the Sky Q box via HDMI.

This then arrives at the TV together. 

But are we then saying the TV is failing to send the audio to the Sonos Arc at the correct time and therefore they are causing the lag? Not that the HDMI input port on the Sonos Arc is causing the delay?

Yes, that is indeed what is being said.

Do your actual ‘built-in’ TV Apps (eg. Netflix/Amazon Prime etc.) play okay and in sync? (Not those installed on the Sky Q box).

The HDFury Arcana splits the video and audio, sending the picture to the TV and the audio directly to the Arc.  The TV shows the picture without delay, the Arc plays the audio without delay, hence no lip sync issues.  (In fact, sometimes there is a bit of video processing lag in the TV, but there is a setting in Sonos that allows me to delay the audio so not a problem.  Playing audio after it arrives does not require time travel.)

Hi, just checked this and yes the Netflix App through the TV has no lip sync issue. But if we watch the same thing through Netflix on Sky Q there is lip sync. 

But then if we watch the Same programme again from Netflix on the Sky Q but take it off HDMI Soundbar and use the TV speakers there was now lip sync.

So from process of elimination is it something to do with the TV relaying the sound to the Sonos Arc? As when it doesn’t relay the sound there is no lip sync issue.

Yes, that comparison process you have done here can often confirm it’s the TV having difficulty processing the audio received from the connected device (Sky Q) and processing the audio data out to the Receiver (Sonos Arc), particularly as there is not a lip-sync issue with in-built TV Apps, so this issue is not going to be the Arc (or it’s cable)… the HDFury Arcana device would likely resolve the matter for you, but the issue here seems to be with the TV, particularly as the Sky Q also plays fine with the internal TV speakers.

@Kara19840 .  I can understand you baulking at the cost of an Arcana just to sort out something you thought was a given.  But there isn’t really any other solution for connected devices.  For me the Arcana was well worth the money, because it means that I don’t need to buy a new TV to get eARC and Atmos.  But I think I would have bought it just for the lip sync - it is the difference between several years of frustration while watching films (in particular) and several years of being perfectly happy.

But you may feel differently.  I think the Arcana does some smart things with the video too, but I’ll get round to reading about that at some point!