The short answer
Check four things in this order: that the cable is in the port labelled ARC or eARC on both devices, that HDMI-CEC is enabled on the TV under whatever brand name it uses, that the TV’s audio output is set to the soundbar rather than its own speakers, and that the audio format is set to PCM if the soundbar does not support the format the TV is sending.
HDMI ARC carries audio backwards along the HDMI cable, from the TV to the soundbar. It is convenient and it is fragile, because it depends on three separate things working: the physical port, the control protocol, and format negotiation. Almost every no-sound complaint is one of those three, and they are quick to check.
Check 1: the right port
Only one HDMI port on a TV supports ARC, and it is labelled, usually in small grey text. On the soundbar there is often only one HDMI output, marked HDMI OUT (ARC) or eARC. Plugging into HDMI 1 because it is first, when ARC is on HDMI 3, produces exactly this symptom and is the most common cause.
While you are there, push both ends firmly. HDMI connectors have no latch, and a cable hanging under its own weight behind a wall-mounted TV can back out just enough to lose the ARC channel while video continues to work.
Check 2: HDMI-CEC
ARC depends on CEC, the control protocol that lets HDMI devices talk to each other. It is off by default on some sets and gets disabled by factory resets. Every manufacturer gives it a different name:
- Samsung: Anynet+
- LG: Simplink
- Sony: Bravia Sync
- Panasonic: Viera Link
- Philips: EasyLink
- Hisense: HDMI CEC or Control
- TCL: T-Link
Enable it on the TV, and enable the equivalent on the soundbar, which is usually a simple CEC toggle in its settings or app. Then power both devices fully off at the mains for a minute and back on, because CEC negotiation happens at startup and a mid-session change often does not take effect until then.
The single most effective fix for ARC problems is a full power cycle in the right order: unplug both the TV and soundbar from the mains, wait sixty seconds, plug in the soundbar first and let it start, then the TV. This forces a fresh CEC handshake and resolves a surprising proportion of cases.
Check 3: the TV’s audio output setting
The TV needs to be told to send audio out rather than to its own speakers. Look for Sound Output, Audio Output or Speakers in the TV’s sound settings, and select HDMI, ARC, Receiver or External Speakers depending on the wording. On some sets, selecting the soundbar by name is required and the generic ARC option does not work.
If the option is greyed out, CEC is not established yet, which takes you back to the previous check.
Check 4: the audio format
This is the cause behind intermittent sound: audio works on one app and not another, or works on live TV and not on a streaming service. Standard ARC has limited bandwidth and cannot carry uncompressed multichannel or the newer object-based formats. If the TV sends something the soundbar cannot decode, you get silence rather than an error.
Find the TV's digital audio output format setting
It may be called Digital Audio Out, Audio Format, or Dolby Digital output.
Set it to PCM
This is the universal fallback. Every soundbar can decode stereo PCM. If sound returns, you have confirmed the cause.
Step up one format at a time
Try Dolby Digital, then Dolby Digital Plus, testing each. Stop at the highest one that works reliably across all your apps.
Turn off pass-through options you do not need
Settings such as Dolby Atmos pass-through or bitstream output cause silence on soundbars that do not support them.
Check 5: the cable
Standard ARC works over almost any HDMI cable. eARC, which carries higher-bandwidth formats, requires a High Speed cable with Ethernet or better, and in practice a cable certified as Ultra High Speed. A cable that is fine for 4K video can still fail for eARC audio, because the audio return uses different pins on some implementations.
If you are troubleshooting eARC specifically, swap in a known-good certified cable before anything else. Cables are the cheapest variable to eliminate.
Check 6: what is plugged in where
There are two ways to wire a soundbar, and the better one avoids the problem entirely:
- Sources into the TV, ARC back to the soundbar. Simple, one cable to the soundbar, and dependent on ARC working correctly.
- Sources into the soundbar, soundbar out to the TV. If your soundbar has HDMI inputs, this passes video through to the TV and takes audio directly from the source. Audio never depends on ARC, which removes the whole class of problem for those sources. The TV’s own apps still need ARC.
If your soundbar has inputs and you are fighting ARC, rewiring this way is often the permanent answer.
Optical is a reliable fallback and worth keeping in mind, but it cannot carry the higher-bandwidth formats, and it does not carry volume control, so you will need the soundbar remote. As a diagnostic, connecting optical and getting sound proves the soundbar and the TV audio path are both fine and the fault is specifically in ARC.
When the sound is delayed rather than absent
Lip sync drift over ARC is common and usually adjustable. The TV will have an audio delay or lip sync setting measured in milliseconds, and so will many soundbars. Adjust one of them, not both. If the delay changes between apps, the app is the culprit and there is often a per-app setting.
What is the difference between ARC and eARC?
eARC is a higher-bandwidth version that can carry uncompressed multichannel audio and object-based formats. It needs support on both devices and a good cable. Standard ARC handles compressed formats such as Dolby Digital fine.
Why does sound work on live TV but not on a streaming app?
Different sources use different audio formats. The app is probably sending a format the soundbar cannot decode. Setting the TV’s digital audio output to PCM confirms it.
Do I need a special HDMI cable for ARC?
For standard ARC, almost any cable works. For eARC, use a certified High Speed with Ethernet or Ultra High Speed cable, since the higher bandwidth is where marginal cables fail.
Why does my soundbar turn on and off by itself?
That is CEC doing its job, and sometimes overdoing it. It follows the TV’s power state. If it is unwanted, disable CEC power control on the soundbar while keeping ARC audio, which many models allow separately.
Is optical or ARC better?
ARC is better for convenience and format support, and it carries volume control. Optical is more robust and completely immune to CEC problems, at the cost of format limitations. For a stereo or basic surround setup, the audible difference is small.
The order that solves it
Right port, CEC enabled under its brand name, full power cycle with the soundbar started first, TV audio output set to the soundbar by name, then PCM as a format test. If eARC specifically is failing, swap the cable. And if the soundbar has HDMI inputs, consider running your sources through it so that ARC only has to handle the TV’s own apps.
