Stereo Upmix kills audio on optical

If switched on I get a somewhat chirping sound (like 1000 cicadas on my roof) via optical

You don’t say what you are sending the optical output to. You would get this if your amp was expecting LPCM. Vero will be sending AC3.

Does the amp automatically switch if you are playing a track with AC3 (Dolby Digital)?

Right, I’m sending it to a new active speaker (Vifa Copenhagen). I don’t know what i expects? I could ask support their though. How does it matter?

An optical connection can send PCM stereo audio or multi-channel compressed audio in Dolby Digital or DTS formats. I can’t see any reason why your Vifa speaker would support multi-channel audio - it barely does stereo by the look of it. So it won’t have the smarts to recognise a DD/DTS stream.

I also figured that a video w/

  • Video: HEVC 4K (3840 X 1604)
  • Audio: AAC 5.1

returns chirps even if upmix is disabled

which means obviously I need to get rid of the chirps, any idea how to change the audio setting to accommodate this speaker

Turn off passthrough. And set channels to 2.0.

Ok, works w/

  • Video: H264 576 (1280 X 544)
  • Audio: AAC 2.1 (UNKNOWN)

though. But, are you saying that passthrough has no effect anyway

You have passthrough and AC3 trancoding enabled. So Vero is transcoding 5.1 to AC3 (DD). It’s still downmixing 2.1 to 2.0 PCM so not using AC3.


  • passthrough off

then AC3 is ignored for playback anyway

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