Before touching a stream, navigate the box's own settings menu and listen for the click or beep it makes when you move between items, then play any local file or a built-in app. If the box is silent there too, the streams are irrelevant and the fault is in the last three links: output format, HDMI path, or the TV and soundbar. If menu sounds play normally and only certain channels are silent, the first two links are in play instead, meaning the audio track or the decoder. This one check splits a long fix list in half and takes fifteen seconds, yet almost no published guide asks for it first.

Many live feeds carry AC3 or E-AC3 5.1 audio rather than stereo AAC. With passthrough enabled, the box does not decode that track at all — it forwards the raw bitstream and expects the TV, receiver or soundbar to handle it. A TV panel that only decodes stereo receives a bitstream it cannot read and outputs nothing. It does not report an error, so you see full video and a dead speaker, which reads as a broken channel. Setting the box's audio output to PCM stereo, or the player's audio mode to software decoding, makes the box decode locally and send something every sink accepts. Sound returns instantly on those channels.

1. 1Selective silence plus perfect video is the signature of a passthrough mismatch
2. 2PCM stereo is the diagnostic baseline, not the permanent setting
3. 3Re-enable passthrough only if a receiver in the chain decodes 5.1

Because two volume controls exist and you may be adjusting the wrong one. The box holds an internal software level, while the TV or receiver holds the real attenuation at the end of the chain. If the box's internal level is at zero you get silence no matter how loud the TV is, and if the remote is not passing HDMI-CEC commands the buttons move a control nobody is listening to. Set the box's own output to maximum, control loudness only at the amplifier or TV, and switch on HDMI-CEC so one remote drives the sink. Where a soundbar sits in the middle, set the TV output to fixed and let the bar do the attenuating.

The handshake. Every HDMI link negotiates capabilities at power-on: which audio formats the sink accepts, which channel counts, whether the return path is active. That negotiation can fail once and then persist, because standby does not repeat it — the devices retain the earlier result. Unplugging the box, the TV and the soundbar from the wall for a full 60 seconds forces a fresh negotiation on the next power-on, which is why it recovers audio that no menu setting reaches. Use the port physically labeled ARC or eARC, remove any switch or splitter from the path while testing, and reconnect them one at a time afterward.

When the same channel is silent on a second device, on a different network. That result clears your entire audio chain and places the fault at the source: a feed pushed with no audio track, or with a track in a codec the encoder mislabeled. No box setting repairs that, and no soundbar change either. Report the channel name and the time rather than describing it as an app problem, because a service can only re-pull a feed it can identify. This is also a fair way to judge a service — how quickly a named broken feed gets fixed says more than any list of features.