ATSC 3.0 no surround audio

Find a show on ATSC 1.0 the has very good and prominent rear channel audio. Then tune to the same station in 3.0. Rears go away completely or to a level so low they can hardly be heard. I am seeing this with HDHR app too, so its not a Channels thing. HDHR app on my LG tv works perfectly for audio.

It works perfectly for me in all scenarios.. I used to have the center channel audio coming out of the back left speaker but Aman did a fix for a channels pre-release and ever since then it works fine for me. That was several months ago. Trust me if I still had a problem my wife would be complaining when "This is Us" was on becuase I only record the 3.0 feed for that... Might be your receiver? Mine shows multichannel audio with dolby digital decoding when I tune a 3.0 station. Not trying to be difficult here, I'm just saying that I don't think it's an ATV bug as I have zero issues with it.

Like I said, I am not the only one seeing this. Long discussion of the Silicon Dust forums about this. I suspect that you may not be getting true surround audio. The ATV by default puts out LPCM audio not a 5.1 Dolby stream. There is a setting to force 5.1, but then you are making the ATV recode the audio and you are not getting the original channel mapping. That is probably why you are hearing surround audio, its being synthesized.

Audio Output Settings

Audio settings on the Apple TV can be adjusted through Apple TV > Settings > Video and Audio > Audio Format .

  • Auto (recommended): Audio will be sent as uncompressed, multi-channel LPCM (up to 7.1 channels and 24-bit)
  • Dolby Digital 5.1: Audio will be sent as Dolby Digital AC3 (5.1 channels and 16-bit)
  • Stereo: Audio will be sent as stereo (2.0 channels)

Nah mine is in auto LPCM. Just tested to confirm, I have 5 channels of completely seperate audio. My marantz is receiving multichannel in and decoding 5.1.
Now my setup may be a little different than yours. My ATV is connected directly to my Sony xbr900h and then EARC to my marantz nr1710. My previous receiver (an 8 year old marantz) had audio issues like you describe, but once I upgraded to a new one I have had no issues whatsoever.

There is your answer. Your SONY is taking the LPCM and recoding it to DD 5.1 for ARC. If you fed the ATV direct by hdmi to your receiver you will see the issue.

Nah it's the same. I had my ATV plugged up direct to the marantz when I first set it up. Same behavior.

Well you are the lucky one. The people on the Silicon Dust forum all see the same issue. I can get fake surround too by looping thru my LG and then back to the amp by ARC. But it’s not proper channel placement.

The issue is specific to the audio broadcast in your market.

I guess so. It's definitely not fake surround sound though. My receiver detects if it is not 5.1 and does whatever the new version of prologic is. In this case it shows multichannel in. My last receiver wouldn't support multichannel in and I got the behavior you have. I'm positive it is true 5.1 becuase I got up on a ladder and listened to each speaker and I do not have any "bleed" from fake surround. (you know where you hear the voices slightly out of phase on the LR speakers etc)
I can also use my shield as well on an atsc 3.0 station and the audio behavior is 100% the same and it sounds identical to the ATV.

No it’s fine as long as I don’t use the Apple TV. HDHR app on my LG tv is sending proper audio to my speakers

It has nothing to do with the Apple TV. You can try the HDHR app on your computer or phone or tablet or android. They will all have the same issue.

The LG app uses a different decoder built into the TV which is working correctly.

Ok, so why does Channels app show the same issue on ATV? The only common thread I see is the ATV and what it is doing with AC-4.

And my LG is from 2018, before AC-4 was built in or ATSC 3.0 support.

Sure, you can describe it that way. The way your local broadcast is encoded is not correctly being recognized by the Apple TV. We found similar issues in other markets that we were able to fix, but so far I don't see an obvious fix in the sample you've sent over.

But people running Shields or Andoid boxes dont seem to have this issue. To be clear I am not at all saying this is a Channels problem since the HDHR app behaves the same. If there was a Channels for LG it would solve my issues.

Would another clip from a different channel be of any help in looking for the issue?

I just installed HDHR 4K in place of a Quattro. I’m in the Seattle Market. Same issue for me - no surround on ATSC 3.0 channels, neither with Channels app or HDHR app. To make matters even worse, my Denon receiver thinks the broadcast is in surround, so it doesn’t upscale, like it would with plain stereo (Denon app shows 5.1 incoming, but surround channels are quiet).

Is this likely to fix itself as ATSC 3.0 use matures? If not, I might just return the 4K and stick with the Quatro.

Are you also using the ATV? How is the device connected to your receiver and which one are you using? If you like, you can host a download of a 30 second clip recorded of a show you know has 5.1 and I'll see if my Shield 2019 Pro will work with it like it does for my ATL ATSC3 channels. Then you know the issue is your setup/device and not the station.

Yes, Apple TV 4K (latest model). HDMI out from ATV feeds HDMI in of receiver.

Thanks for the offer, but I'm all but certain the difference is related to the ATSC 3.0 encoding, and not my setup. For example, I also have an HDHR Quatro for which surround works fine, as does the ATSC 1.0 channels with the Flex 4K. Plus, the symptoms I have are nearly exactly as posted on various other forums, including this one.

In short, ATSC 3.0 feels a little too much "bleeding edge" for my taste at the moment.

Are you still having the same issues?

If you can make a 15s clip from each station, and name them atsc3-charlotte-.mpg and email to support, that will be very helpful.

@kentrd Can you do the same, and name them atsc3-seattle-.mpg

Channels Support - HDHomeRun FAQ

yes same issues on ATSC 3.0. Audio is basically stereo, no surrounds.