When your Fire TV Cube has a picture but no sound, it's usually a quick setting or connection fix. The Cube sits between your TV and other devices, so the audio path can get a little more complicated than with a simple streaming stick.
Check Your Remote and TV Volume First
Press the volume up button on your Fire TV remote. Make sure the TV itself isn't muted using its own remote. I'd start here because the Cube's remote can control your TV's volume via IR, but if the TV remote is on mute, you won't hear anything.
Also, check the volume on any external sound system you're using, like a soundbar or AV receiver. Sometimes the Cube is sending the signal just fine, but the output device is turned down.
Verify the Audio Output Setting
On your Cube, go to Settings > Display & Sounds > Audio. Look at the Audio Output Device setting. This is the most common culprit.
If you're using your TV's speakers, this should be set to TV. If you have a soundbar or receiver connected to the TV via HDMI ARC, it might show up here. Selecting the wrong output will route sound to a device that isn't on or doesn't exist.
Restart the Fire TV Cube
Go to Settings > My Fire TV > Restart. This soft reboot clears out temporary glitches that can affect audio processing. Give it a minute to fully boot back up.
For a more thorough reset, you can unplug the Cube's power adapter from the wall for about 30 seconds, then plug it back in. This is different from just putting it to sleep with the remote.
Inspect Your HDMI Connections
The Cube has an HDMI input and an HDMI output. Your cable box or game console plugs into the input, and the Cube's output goes to your TV. A loose cable at any point can kill the sound.
Unplug and firmly reseat the HDMI cable going from the Cube to your TV. If you're using the passthrough feature with a cable box, check that input cable too. Try a different HDMI port on your TV if one is available.
Change the Audio Format to PCM
Head back to Settings > Display & Sounds > Audio and find Surround Sound or Audio Format. If it's set to Best Available or a specific format like Dolby Digital, try changing it to PCM.
PCM is a simpler, uncompressed format that every TV and soundbar can play. Some older audio systems can't decode the more advanced formats the Cube tries to send, resulting in silence. This fix takes about 30 seconds and often solves it.
Check the Specific App
If you only have no sound in one app like Netflix or Disney+, the problem is likely with that app, not the Cube's system. First, try playing a different show or movie within the same app.
If that doesn't work, force close the app. From the home screen, press and hold the Home button on your remote, select Apps, highlight the problematic app, press the menu button (three lines), and choose Force stop. Then reopen it.
Disable and Re-enable HDMI CEC
The Cube uses HDMI-CEC to control your TV and audio system. Sometimes this communication gets confused. On your Cube, go to Settings > Equipment Control > Manage Equipment > TV.
Try turning HDMI-CEC Device Control off, wait a moment, and then turn it back on. This can re-establish a clean handshake for audio control between your devices.
Update the Fire TV Cube Software
Audio bugs are frequently patched in software updates. Navigate to Settings > My Fire TV > About > Check for Updates.
If an update is available, install it. The Cube will download and restart. It's a good habit to check this every so often, as Amazon pushes updates that fix these kinds of issues.
Test with a Different Audio Source
To rule out a problem with a specific input, try using the Cube's built-in apps like Prime Video or Freevee. If those have sound, but your cable box (connected through the Cube's HDMI input) does not, the issue is with the passthrough setup or the cable box's settings.
You can also try plugging the cable box directly into the TV to see if sound works that way. This helps pinpoint where in the chain the problem is happening.
Reset Your Audio Settings
If you've changed a lot of settings, it can be easier to start fresh. Go to Settings > Display & Sounds > Audio and look for an option to reset audio settings to default.
This won't erase your apps or logins, but it will clear any custom audio or volume leveling configurations you've made that might be causing a conflict.
