At just under £800, the latest soundbar from wifi audio specialist Sonos is an expensive but simple and very effective way to turn the sound from your TV into a cinema-like experience. But there is just one problem – it doesn’t always work as planned.
It is a problem that dogs numerous soundbars; depending on how you go about watching the television, the sound can come slightly before or after the picture, creating a jarring lip-sync issue. Once noticed, even a minor delay in the picture or sound can be infuriating.
So why does such an apparently simple problem affect such advanced tech? The answer lies in how soundbars are connected to the TV. Today, the majority are with an HDMI cable using audio return channel or ARC for short.
ARC is designed to have just one connection between your TV and sound system, feeding the video to your TV in one direction, and returning the television’s audio to the soundbar in the other. When it works, it is simple and effective. The trouble is, it relies on the TV sending the audio in time with the picture so that it can be played with perfect synchronisation.
When things go wrong it can be infuriating – sometimes the picture can appear after the sound, which is most obvious when someone is speaking on screen and their speech doesn’t match up with the movement of their lips. Once you notice it, you won’t be able to unsee it.
When simply watching Freeview, Freesat or one of the various apps directly on your TV, ARC usually handles the synchronisation without issue. The problem comes when you attempt to watch some other video source connected to your TV, and is particularly prevalent with broadcast TV boxes such as Sky’s Q or Virgin’s V6.
When watching this way, the picture and sound are passed from the box to TV via the HDMI cable. The TV then splits the picture and sound, and feeds the audio to the soundbar via ARC down another HDMI cable. When the audio arrives at the soundbar before the picture is displayed on the TV, it creates the dreaded lip-sync problem.
If the automatic systems designed to correct timing issues fail, most set-top boxes, TVs and soundbars have ways to manually add a delay to the audio so you can synchronise it with the picture. But getting it right is a tedious process, which may leave someone questioning why they have to tweak a piece of technology that they have spent so much money on.
These tools work fine when the picture is behind the sound, but if the sound is delayed and arrives after the picture you’re often out of luck. And it is this issue that plagues all brands, costs and sizes of device. If the audio arrives at your soundbar after the picture is displayed on TV, delaying the audio does nothing. And worse, the delay can be variable depending on the content you’re watching, and the sound format it was shown in.
People often point the finger of blame straight at the soundbar, but the anger is often misplaced. The culprit is more likely to be the set-top box or the TV further up the chain. That leaves those unlucky TV watchers contacting call centres for each of their various bits of kit, ending up in a merry-go-round of agents blaming each other.
It is such a common and irritating problem that various online forums are filled with people trying to work out homemade fixes, often with bizarre sets of configuration steps that might as well include some sort of prayer and a dance. There’s even a cottage industry of – often high-priced – devices that attempt to solve the issue. These third-party companies make and sell small gadgets to solve what is essentially a software failing.
People often ask how they can avoid such problems, but it’s very hard to know in advance whether you’ll be hit with incurable lip-sync malfunctions. In the last decade of testing various combinations of TVs, set-top boxes and soundbars, I have had some sort of lip-sync issue at least half the time. That is the reason why I still use a separate home theatre system with a dedicated receiver, rather than one of the significantly sleeker, cheaper – and just as good-sounding – soundbars.
There is hope. The latest advance in HDMI connectivity, called enhanced audio return channel (eARC) is designed to both carry higher-quality sound formats and to solve lip-sync issues. But I’m not holding my breath.
ARC was meant to solve the issues caused by the older optical connections it replaced in 2009 but could not.