Peeps, don't go spending money on expensive HDMI cables. All the cable is there for is to deliver the digital information to the decoding appliance. For image this will be your TV. For audio it could be an AVR, soundbar or again the TV. The puck will have a digital TMDS 'clock' which should syncronise the audio to the image, HDMI will then connect with your appliance and it's 'clock' should decode the incoming signal at the right time stamp, often referred to as the handshake. Sometimes a new cable will, by simply being a new connection, give a better handshake. If the clocks are wrong then the audio will drift again.
That's a very simplistic answer and there's more to HDMI than syncronisation and the latest version of HDMI is 2.1 (and 2.1b). All you need is a working cable capable of the current specifications and can be confirmed by scanning the QR code on the box it came in. Make sure that the ends of the cable and fully inserted in both the puck and the TV and secure.
What's going wrong with Sky is that the TMDS clock is not working as it should and is a software problem. Early Apple TV pucks suffered from the same problem. Now the latest ATV+ is far more stable and I've never encountered lip sync problems at all, I'm very sensitive to it, my wife not so, which is why I had to return my Stream.
Quite why Sky is so far behind the curve ball with Stream is possibly down to doing them on the cheap and what is needed is a completely new puck as the best way to get over the problem. It should be obvious to Sky by now is that the firmware updates and not working for 100% of customers. Even high end equipment can have software problems so it's not unique. Where Sky is letting their customers down is in their somewhat head in the sand approach early on blaming the problems on customers' own equipment. Now there is an acknowledgement but Sky still insist on customers paying a high price for a poor service, which is totally wrong.
Lip Sync issues - Sky Stream
