| Problem | Likely Cause | Solution | | :--- | :--- | :--- | | | TV is set to PCM | Change TV audio settings to "Bitstream" or "Auto" | | Sound from Front Left also comes from Surrounds | AVR is in "Dolby Surround Upmixer" mode | Switch to "Direct" or "Straight" mode | | Center speaker is silent | Player is downmixing 5.1 to 4.0 | Check HDMI cable; ensure media player set to 5.1 (not 2.0) | | Subwoofer is quiet | LFE channel is missing or crossover is 40Hz | Set AVR crossover to 80Hz; ensure test file includes LFE | | Video plays but no audio | Codec missing | Use VLC (PC) or Infuse (iOS/tvOS) to software decode |

You might ask: Can’t I just search "5.1 test" on YouTube?

ffmpeg -f lavfi -i "aevalsrc='0.1*sin(2*PI*440*t)':channel_layout=5.1:duration=30" -c:a ac3 -b:a 640k test_5.1.mkv