Poor sound quality via TV optical output

[krabapple]

When I try 2.0 content from the Apple TV or the Playstation 5 it sounds as it should. When I change and try 5.1 material it sounds good when the apple TV downmixes it to stereo but not when I leave it to the TV or Playstation 5. I shall also test with the internal speakers and see how it reacts to the differences. I'll report back regarding that.

That suggests that the TV and Playstation are not set to downmix the content correctly.

 

[ZolaIII]

That suggests that the TV and Playstation are not set to downmix the content correctly.

I think it is related to pore and unproper OEM implementations (as suggested before).
Take a look at last couple of posts hire:
https://www.audiosciencereview.com/...easurements-of-sound-blasterx-g6.7016/page-23

 

[Yoni842]

Sorry I'm bumping the thread, but I wanted to update a bit and consult with you. So in the end I bought a new DAC (SMSL M100 MKII) and replaced the cheap ****** one. The sound has changed for the better in its character, there is a strong bass, no jitter, etc., but still not exactly what I am looking for. In movies (and also music) I still do not hear this rich sound with the opened stage. Speech sounds weak, explosions sound loud, i.e. there is no balance. I just can not believe the difference between this and the sound that came out of my computer's motherboard. It's like the TV optical port outputs like 8-bits audio or something.
The two options I am thinking of now are:
1. Buy something like NVIDIA SHIELD and see if through it the sound is better.
2. It is possible that the optical output of the TV just outputs a bad sound, and then I have a question: my TV has an HDMI eARC input. Is there a way to transfer the audio of the TV through this port and then connect it to the DAC I bought? I've seen all sorts of audio extractors like this for example: https://www.aliexpress.com/item/400..._pvid=655ab78d-6fce-49bd-a139-19eec9bfaffd-al -a139-19eec9bfaff2-0 & pdp_ext_f =% 7B% 22sku_id% 22% 3A% 2210000001417582733% 22% 7D

Of course all this assuming that the HDMI eARC port on the TV really outputs a better sound.

 

[Pluto]

In movies (and also music) I still do not hear this rich sound with the opened stage. Speech sounds weak, explosions sound loud, i.e. there is no balance.

Forget about any audiophile claptrap. What you have here, almost certainly, is a poor fold-down from 5.1 to the two channel TV optical output. The only workaround for that will be to access the incoming audio stream, decode and reproduce it independently of the TV. Are you absolutely certain that the TV is not performing any of the dynamic adjustments that modern TVs notoriously perform in their default state?

Sadly, I do not think there is a simple and obvious solution to your problem but you really do need to be aware of the nature of the incoming format. Without that knowledge, it's a bit like trying to plot a course to a destination from an unknown starting point.

I would look again at the earlier part of this thread and follow through the tests you were advised to perform. Only then will you have an idea of what is actually happening and be able to deduce a remedy.

 

[Yoni842]

Are you absolutely certain that the TV is not performing any of the dynamic adjustments that modern TVs notoriously perform in their default state?

Thank you for your help!
The TV audio is set to PCM instead of Auto, so I guess that it's not performing any of those dynamic adjustments, if I got you right.
Sorry but what do you mean by "the nature of the incoming format"? For example, this situation applies for all content played via the TV's Netflix app, and also when I play movies from my pc in the TV Plex app or even when playing movie through the TV USB port.

 

[Pluto]

The TV audio is set to PCM instead of Auto, so I guess that it's not performing any of those dynamic adjustments

That could be a dangerous assumption. You need to go through every single audio option and satisfy yourself that nothing is being done to modify the dynamics. There is no guarantee that such a “totally neutral” option even exists.

Use one of several available test videos to understand what the TV is doing to the incoming stream, but to accomplish these you need to be sure exactly what the incoming stream consists of. Some soundtracks are designed in such a way that they do not fold down to 2.0 all that well. By the time you combine that with flawed implementations and software bugs it can be difficult to know where you stand but you have to work through the problem slowly and logically. There is unlikely to be a quick, simple fix. You need to find a test source of known 5.1 material and examine how your rig is folding down the 5.1 to 2.0.

Bear in mind that YouTube (a good source of test material) does not, in itself, deliver 5.1 audio, only 2.0. If you download the test video you want to use, the audio content might be what you need but I know nothing about what, if anything, YouTube might do to compress or otherwise modify content for reasons only they fully understand.

The essence here is you have to test with known, reliable, content. And you have to face the possibility that your rig is doing extactly what it is supposed to, only you don't like the result.

 

[SMc]

The manual says: Digital audio is only available with 5.1 channel broadcasts.

Any guesses? Surely the tv will output something with stereo or mono programs. No fold down would explain losing center channel dialogue sounds.

The Expert Setting menu includes a Pass-Through option. There's also an Adaptive Sound+ mode that "Provides optimized sound quality by analyzing the viewing space and the acoustic components of the content." This is selected in Intelligent Mode.

I would double check that Pass-Through is selected and Adaptive Sound+ is not.

 

[jtwrace]

I've been wondering if there's any advantage to using an HDMI to Optical converter. Mainly due to my darn TV auto switches the output away from the optical out setting.

Something like this:
https://www.monoprice.com/product?p...KNsmVPA7PQTtfI8X-l-QRKo61uVNtxtBoCfQoQAvD_BwE

 

[Yoni842]

@Pluto I've just downloaded a DTS HD Master Audio Sound Check file which is in DTS-HD MA 5.1 format. I connected it with a usb drive to the tv usb port and tried to play it. and a message appeard stating that the audio formats in the video are not supported, and the video was displayed without any sound.
And just wanna point out that when I played the file on my pc with the MPC-HC software the sound did work fine, however with the built-in Windows player no sound came out.

 

[Yoni842]

An hypothetical question: if I'll watch movies with something like Nvidia Shield connected to the TV, is there a chance that the audio processing would be better? (the speakers will be still connected to a dac which is connected to the tv via optical, so I doubt if anything will be changed, but still I wanted to consult you).

 

[Pluto]

I've just downloaded a DTS HD Master Audio Sound Check file which is in DTS-HD MA 5.1 format. I connected it with a usb drive to the tv usb port and tried to play it. and a message appeard stating that the audio formats in the video are not supported

Well you have me at a loss. I can only assume that your TV truly doesn't support the format. I have played this file (and its 7.1 counterpart) with exactly the output I would expect and I have a basic Samsung TV with no fancy features whatsoever. The TV's optical output is connected to a standard stereo DAC and speakers.

Only the LFE gave no output and that is to be expected, I suppose, although I don't understand why at least some of the LFE isn't routed to L & R which, in my case, are large speakers capable of decent LF response.

 

[ZolaIII]

@Yoni842 I doubt Nv Shield would make a difference (Android doesn't have proper Dolby's support and probably never will). Best solution would be a DAC with a proper support for decoding the format (and there is very little of those). Unfortunately you're TV obviously doesn't support the format and there for can't do a conversion to two channel PCM (to DAC). MPC does the conversion on general purpose CPU core's. It remains to be checked if the decoding support whose embedded into FFmpeg and if so is it also supported by ARM. If it is you can use a player based on FFmpeg on Android (or Linux) with an Arm device (TV box, developer board with HDMI or Smartphone with e-Arc support with appropriate cable) which still ain't exactly hustle free but it's at least cheap way of getting there. Alternatively you could transcode the audio in video to two channel PCM before use with some of transcoding software which can decode it. On average processor it shouldn't take more than 5~10 min for future-length muvie. Hope that helps.

 

[DVDdoug]

Only the LFE gave no output and that is to be expected, I suppose, although I don't understand why at least some of the LFE isn't routed to L & R which, in my case, are large speakers capable of decent LF response.

The downmix is not supposed to include the LFE, just the "regular bass" from the other channels.

 

[Pluto]

Unfortunately you're TV obviously doesn't support the format and there for can't do a conversion to two channel PCM

My Samsung is an earlier, cruder model yet it does this without blinking.

Is the apparent failure of a newer model to do this simple fold-down not rather surprising?

 

[dasdoing]

my dac has to run at 48000...at 44100 the TV out produces artifacts

 

[ZolaIII]

My Samsung is an earlier, cruder model yet it does this without blinking.

Is the apparent failure of a newer model to do this simple fold-down not rather surprising?

Probably a cost saving (for a licence) measure on new ones. We live in the era of Open Source and people/manufacturers don't exactly look with approval on property one's especially if they are not essential and cost a lot. To make things worse manuals (for TV's and other stuff) today don't contain info on supported codecs (precisely or at all) and such stuff.

 

[Ajant]

If it's any help I experienced the exact same scenario as Yoni explained at the beginning of this thread when switching from an old Samsung Plasma TV (2011) to a new one. I made the mistake of buying a cheap $20 DAC to use between the optical out of the TV and the input of my stereo and the sound was appalling, exactly as Yoni described. I have since replaced the cheap DAC with a Topping E30 and the sound is now excellent and back to where it should be.

 

[EdTice]

If it's any help I experienced the exact same scenario as Yoni explained at the beginning of this thread when switching from an old Samsung Plasma TV (2011) to a new one. I made the mistake of buying a cheap $20 DAC to use between the optical out of the TV and the input of my stereo and the sound was appalling, exactly as Yoni described. I have since replaced the cheap DAC with a Topping E30 and the sound is now excellent and back to where it should be.

Now that you've bumped this thread, I might as well make some comments since others may hit it. It wasn't mentioned anywhere in this thread but most AVRs have a way to show the input signal and the speakers used in output. Optical/TosLink can only carry two channels, not 5.1 content. So if you are using optical out of the TV, you are only getting two channel audio out of the TV.

Many apps (YouTube is somewhat guilty and AirPlay is obscenely guilty) try to detect the capabilities of the playback device and they will send a signal compatible with the capability of the end-device (HDMI provides this meta-data). The chosen upsampling can be awful.

I have an older Yamaha receiver with which I don't usually use AirPlay. I'm generally happy with it for bedroom music. I tried Airplay the other day and the receiver was set for ProLogic decoding. Things sound bizarre and I can't figure it out. The display shows that all speakers are in use but I'm getting sound only from the center channel. But if I set for straight decode (where I expect stereo output) I get an upmixed sound using all speakers including the surrounds.

The only explanation I can come up with is that the upmix somehow decided to make the L/R play identical sounds with the delta in the rear and the ProLogic decoder decided that mean that everything belongs in the center. But who knows. Source folding is constantly problematic. We've even seen bugs in AVRs reviewed here where source material mapping caused the performance to degrade for unknown reasons.

Back to the OPs question, fortunately my AVR has a "2 channel stereo" mode where it will refold everything itself. I think they all have this.

I don't understand some of the earlier comments. An HDMI audio extractor with digital output is a pure digital transformation. Those should be fine to use. But they won't necessarily solve the problem as the TV will still be doing the folding.

Find a used processor or AVR with HDMI eARC. The TV should pass the audio unmolested via ARC and let the processor handle it. I just bought a UMC-200 from another ASR member for $200 used. You can find similar used devices in that price range. You don't care about features other than eArc input and good SINAD out of the RCA jacks. Let the AVR/AVP do the source material folding and you should be fine.

 

[EdTice]

Here is a UMC-200 for $200. I have no association with the seller But Facebook offers some buyer protection

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[krabapple]

Now that you've bumped this thread, I might as well make some comments since others may hit it. It wasn't mentioned anywhere in this thread but most AVRs have a way to show the input signal and the speakers used in output. Optical/TosLink can only carry two channels, not 5.1 content. So if you are using optical out of the TV, you are only getting two channel audio out of the TV.

Optical can carry lossy compressed multichannel audio (typically a Dolby bitstream, if it's TV). To use it you have to enable your TV to output bitstream/raw audio data. Any AVR made in the last decade or two will be able to decode it.