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Discussion Starter · #1 ·
I have just bought a new LG SK10Y soundbar to complement my LG B7 OLED display and my PS4 Pro. I'm following the instructions on the manual, so my setup is PS4 -> HDMI -> TV -> HDMI ARC -> SK10Y. Dolby Atmos works fine via the TV's Netflix app, but I have concerns about which audio settings to use with the PS4. The 3 options are Linear PCM, Dolby bitstream and DTS bitstream. Choosing any of these will produce sound, however, choosing Dolby bitstream causes a noticeable delay in sound (around 1 - 1.5 seconds). So that's out of the question. I don't know whether to choose PCM or DTS, which one is the correct one? I've read somewhere that HDMI ARC causes linear PCM to default to stereo, which I do not want. I also do not want to plug the PS4 into the SK10Y, as that apparently doesn't allow me to do 4K in HDR. What would be the correct way of hooking things up with which audio format to enable me to use 4K HDR and surround sound?
 

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The linear PCM is lossless over HDMI and should be the best option in theory. DTS is compressed or 'lossy', but allows the receiver/soundbar to do the decoding. I don't know if the soundbar will display the type of signal if it didn't decompress it. May have to play with that on my setup soon.


For Blu-ray, you may want to use Bitstream. This setting is only accessible while you are watching a Blu-ray/DVD and is found by pushing the "Options" button and looking under audio.


Play around with it. In the end, go with what sounds best to you. You may not find a huge difference in general perception anyway.
 

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Discussion Starter · #3 ·
The linear PCM is lossless over HDMI and should be the best option in theory. DTS is compressed or 'lossy', but allows the receiver/soundbar to do the decoding. I don't know if the soundbar will display the type of signal if it didn't decompress it. May have to play with that on my setup soon.


For Blu-ray, you may want to use Bitstream. This setting is only accessible while you are watching a Blu-ray/DVD and is found by pushing the "Options" button and looking under audio.


Play around with it. In the end, go with what sounds best to you. You may not find a huge difference in general perception anyway.
So whoever wrote "HDMI ARC causes linear PCM to default to stereo" was wrong? I'll have to look for a way to verify whether the SK10Y is getting stereo or actual 5.1 from my PS4... Any idea how to do that?
 

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Using an optical cable will cause it to default to stereo. Guess I could be wrong on ARC causing it to do so as well. I will have to test, I guess.


EDIT: I was apparently wrong. While it should be possible, I am now also reading everywhere that no TVs are passing the signal through the TV as you suggested. I have my setup going through the soundbar first which is allowing it, but I have HDR pass through. Apologies.


EDIT2: I could have sworn I was using PCM even before I went straight to the soundbar, but perhaps not. Just also found on rtings.com this:


PCM is an uncompressed audio format, which means it will theoretically have the best overall sound quality, as no information has been removed to facilitate transmitting the signal. PCM is sent unencoded by the source, meaning the full, unpacked ‘instructions’ for what sounds to play are sent directly from the source to receiver, and then on to the speakers.
Unfortunately, this makes for a signal that is more difficult to transmit. No TV seems to be able to pass a 5.1 PCM signal through to a sound system, so sending a PCM signal to or from a TV will downgrade the signal to 2.1 (two speakers + one subwoofer), thus eliminating the extra channels necessary for surround sound.

PCM 5.1 can work with a receiver that supports the format, so if you want uncompressed sound, you’ll need to forego passing the audio through your TV, and instead output the sound directly from the source (one that outputs PCM 5.1) to the receiver. Note that only HDMI can transmit a 5.1 PCM signal. Digital optical is only capable of transmitting a 2.1 or 2.0 PCM signal.

When to use PCM

For 5.1 audio, use PCM sound only if you

  • Output audio directly from each source device and to the receiver.
  • Output this audio via HDMI, and not optical.
 
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