Live NetTV v5.0How to use the test
- Open this page on the device you watch on, so the sound goes through the same TV, soundbar or headphones as your shows. On a Fire TV, use the Silk browser; on Google TV or Android TV, any installed browser works.
- Press Start test and turn the volume up. Watch the circle and listen for the beep.
- If the beep comes after the flash, move the slider right. If it comes before, move it left. Stop when they land together.
- The number shown is how far your sound is out. Use it with the settings below.
The browser's own output delay is taken out automatically when the browser reports it, so the result is the delay added after the browser: the TV, soundbar, receiver or Bluetooth link.
How much delay is a problem?
The broadcast standard ITU-R BT.1359 found that viewers start to notice when sound is about 45 ms early or 125 ms late, and find it unacceptable at about 90 ms early or 185 ms late. Sound that is slightly late is easier to accept than sound that is early, because in real life sound always reaches you a little after the light.
How to fix out-of-sync sound
- Fire TV: go to Settings › Display & Sounds › Audio › AV Sync Tuning and adjust until the ball, tone and flash on its test screen line up. With Bluetooth connected it tunes Bluetooth separately. Not every Fire TV model has it, and Amazon's home theater setups with Echo speakers use Lip Sync Tuning instead.
- TV or soundbar: look for Audio delay, Lip sync or AV sync in the sound settings. Some TVs also have an "Auto lip sync" option for HDMI ARC/eARC.
- Sound ahead of the picture: turn on Game mode or switch off motion smoothing on the TV, which removes picture processing delay.
- Sound behind the picture: try switching the Fire TV or Android TV audio format from Dolby Digital Plus to PCM / Stereo, and avoid Bluetooth for TV if you can.
- Only one app is out of sync: the setting on the device will not fix that. Clear the app's cache or reinstall it; see Firestick no sound for the steps.
If the remote does not control the soundbar volume, turn on HDMI-CEC; the HDMI-CEC name finder shows what your TV brand calls it.
Frequently asked questions
Why is my Firestick sound out of sync?
The most common causes are Bluetooth headphones or speakers, TV picture processing, and Dolby audio being decoded by a soundbar. AV Sync Tuning under Settings › Display & Sounds › Audio adjusts it on models that have the option.
Is this test accurate?
It is good to within a few tens of milliseconds, which is enough to set an audio delay. Browsers on some TVs do not report their own output delay, so results there can read a little high.
Why is Bluetooth sound always late?
Bluetooth audio is compressed and buffered before it plays, which commonly adds 100 to 300 ms. Wired, HDMI ARC or eARC connections add far less.
Does the page record or send anything?
No. The beep is made in your browser and nothing you do on the page is stored or sent.
Sources
- Amazon: Audio Is Out of Sync on Your Fire TV Device
- AFTVnews: Fire TV sticks gain an audio/video sync adjustment option
- ITU-R BT.1359: Relative timing of sound and vision for broadcasting
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