If you're not happy with the quiet, dark sound coming from your TV speakers, a sound bar can seriously improve your movie watching experience. But while most soundbars are space-saving and easy to connect, they still feature an occasional quirk or two, most notably an audio delay that desynchronizes dialogue with mouths moving across the screen.
How your TV and soundbar get out of sync
I have tried and reviewed countless TVs and soundbars, and audio lag is an extremely common problem. A lot of people fall for a certain make or model of soundbar, but it's not always that simple. Often times, this delay is inherent in the way televisions and soundbars decode sound.
"It's a complicated problem," says Allan Devantier, vice president of audio research and development at Samsung. "You have all of these different audio formats, so there are a lot of calculations the TV has to do to unbox it all."
Specifically, when you watch a Blu-ray or stream a movie on Netflix, that audio is encoded in a certain format, like DTS or Dolby Digital. When this signal is sent to your TV or soundbar, the device has to decode the sound in order to play it on your speakers, and this process takes time. We're usually talking about milliseconds, but time nonetheless – and higher bit rate formats (like multichannel Dolby Atmos) can take longer than a low bit rate stereo track, resulting in a more noticeable delay.
If you play this sound on your TV speakers, your TV does all the unpacking, so it may delay sending video and audio until that the process is completed. But when you introduce another product, like a sound bar, your TV can decode the video while your sound bar decode the audio. If the TV doesn't know exactly how long your soundbar will last, it may send the video before the soundbar is finished, resulting in a disastrous mouth-to-screen mismatch. Add to that any other processing you do, like motion smoothing on your TV or 'virtual surround' type features on the soundbar, and you're pretty much guaranteed to have out of sync dialogue. Manufacturers are trying to solve this problem on their own, but there is little they can do.
"We analyze all the different variations in stream that can come in and calculate the best estimate of how we should delay the audio and video to keep them in sync," says Devantier. "But that can only be an estimate." He also tells me that their math assumes a Samsung soundbar, so you might notice more lag if you're using products that weren't designed to work together.
All hope is not lost, however. There are several things you can do to complete this challenge, even if you don't have any branded gear. After hours of testing with countless soundbars over the years, here are some solutions I have found.
Adjust the audio delay on your TV or soundbar
Let's start with the obvious: Many TVs and soundbars have a built-in 'audio delay' or 'lip-sync' setting that aims to play the two in tandem. You'll find this in the audio settings on your TV and / or soundbar, and if you're lucky, adjusting it a few notches may resolve the issue.
Unfortunately, many TVs and soundbars only allow you to adjust it in one direction: delay the audio. But if your audio is out of sync because the audio is behind the video, that is. already delayed – delaying it further obviously will not help. Ideally, your TV or soundbar would offer negative delay, sending audio a few milliseconds earlier (or video a few milliseconds later). Many devices I have tested including the LG TV, Vizio TV, Vizio Soundbar, and Samsung TV that I own do not allow two-way tuning, which makes the functionality virtually unnecessary against audio delay. To their credit, however, Devantier tells me that Samsung has done a lot of work on this issue over the past few years, and the 2020 models now have the option of adjusting its lag in either direction – although I don't. haven't tested its effectiveness myself yet. .
If you are lucky, your streaming box or Blu-ray player may have its own audio tuning function. It's less common, in my experience, but worth it. If none of these lip-syncing features solve the problem, you'll need to get a little more creative.
Disable audio and video processing
Go through your TV and soundbar settings to discover all the features that somehow change video and audio. In particular, browse your soundbar menu for equalizer settings, presets such as "Movie" and "Sports" modes, dialogue boosters and volume levelers, or features such as surround sound. "Virtual 3D". Turn them all off and you should find that the delay is much smaller, if not eliminated. All of these features require processing from your device, which takes a few milliseconds of time.
Change the audio format on your TV
In my experience, this lip-sync issue is most common when sending audio from your TV to your soundbar using HDMI ARC or the optical output. Your TV sends audio to the soundbar, the soundbar takes a moment to decompress the signal, and sends it out once the corresponding video has reached your eyeballs.
However, your TV may be able to perform this audio decompression process on its own, removing the load from your soundbar and allowing the two to stay in sync. In your TV's audio settings, see if you can change the audio format to PCM instead of Dolby Digital, bitstream, or passthrough. I found this eliminated the lag on all of my TVs.
However, this has its own drawbacks. Some TVs cannot decode certain formats, like DTS or Dolby Atmos, which means this trick will not work on movies encoded in these containers. It can also mean that you are losing multichannel audio. If your soundbar only has two speakers that's fine, but if you have a 3.1 or 5.1 soundbar, you'll lose your surround sound, which makes this solution a no-starter.
Connect your source to the sound bar instead of the TV
The best solution, in my opinion, is to reconfigure the way your devices are connected. If your Roku is connected to your TV, which then sends audio to your soundbar via HDMI ARC or optical, you'll need to use the (often flawed) solutions above to mitigate the delay. But if you plug your Roku into the soundbar and then stream the video through the soundbar to the TV via HDMI, any delay caused by the audio processing will go away, as your soundbar will wait to send the video to the TV. until all her work is done. audio. (This may introduce video delay instead, if your TV does its own processing, like motion smoothing, but you can use the lip-sync feature on your soundbar to delay the audio to match. .)
While this is the ideal solution, I mention the latter because it has one big drawback: most soundbars don't have a lot of inputs. In fact, most affordable soundbars only have a single HDMI In port, which means if you've got a Roku, Blu-ray player, and game console, you won't be able to. plug them all into the soundbar at the same time (unless you're using an HDMI switch, which just introduces more wires and complexity). It also doesn't work if you use smart apps on your TV to watch Netflix or if you watch local channels on an antenna plugged into your TV. Under these circumstances, there is no external box to plug into the soundbar, so you are forced to route the audio to the soundbar via HDMI ARC or delay inducing optics.
You can see how such a simple thing quickly gets complicated. If you're lucky, your TV or soundbar will be one of those that will allow the lip sync feature to adjust in either direction, or at least you'll have a soundbar. high end with enough inputs for all your devices. Otherwise, you'll have to play around with the above adjustments to get close enough.