Noisy digital audio on LG TVs

[Falco]

I have a LG oled C2 and was really disappointed with the sound via toslink out to the optical input of my Peachtree audio decco65 (stereo amp) I had audible dropouts every few seconds.

In the end I fixed it (sort of) with a prozor PRR025 eARC HDMI audio extractor. From the prozor I have a toslink to the same optical input of the Peachtree. Somehow this thing shows up on the TV as a Panasonic soundbar, but it works without dropouts and sound quality is quite reasonable.

Edit: this is the prozor

PROZOR 192KHz DAC Converter ARC Audio Extractor

PROZOR 192KHz DAC Converter ARC Audio Extractor, HDMI ARC Audio Extractor Support 5.1ch Digital ARC Audio to Analog Stereo Audio RCA L/R Optical and 3.5mm Jack ARC Audio Adapter for TV

prozoreu.com

However if I would like to improve still, how should I accomplish that? I guess the toslink out of the C2 TV is a no go as that signal is just very poor. Are there better stereo HDMI audio extractors on the market that would give an improvement?

 

[lennyanders]

I myself did by getting a BlueSound node and have almost no problems with audio signal. Every once in a moon somehow I have a small glitch when watching YouTube, but no other service. That was a really expensive solution and I don't particularly like the BlueSound software wise. Let's hope the Win Ultra will be the a bit cheaper and a lot better BlueSound Node killer.

There also a bunch of Amps and most of AVRs with eARC built in, if you want an all in one thing. I myself don't need an amp though.

 

[Falco]

I myself did by getting a BlueSound node and have almost no problems with audio signal. Every once in a moon somehow I have a small glitch when watching YouTube, but no other service. That was a really expensive solution and I don't particularly like the BlueSound software wise. Let's hope the Win Ultra will be the a bit cheaper and a lot better BlueSound Node killer.

There also a bunch of Amps and most of AVRs with eARC built in, if you want an all in one thing. I myself don't need an amp though.

Thanks for your suggestion, however I'm indeed not in the market for a new amp. Pretty happy with the Peachtree still.

 

[Roland68]

I have a LG oled C2 and was really disappointed with the sound via toslink out to the optical input of my Peachtree audio decco65 (stereo amp) I had audible dropouts every few seconds.

In the end I fixed it (sort of) with a prozor PRR025 eARC HDMI audio extractor. From the prozor I have a toslink to the same optical input of the Peachtree. Somehow this thing shows up on the TV as a Panasonic soundbar, but it works without dropouts and sound quality is quite reasonable.

Edit: this is the prozor

PROZOR 192KHz DAC Converter ARC Audio Extractor

PROZOR 192KHz DAC Converter ARC Audio Extractor, HDMI ARC Audio Extractor Support 5.1ch Digital ARC Audio to Analog Stereo Audio RCA L/R Optical and 3.5mm Jack ARC Audio Adapter for TV

prozoreu.com

However if I would like to improve still, how should I accomplish that? I guess the toslink out of the C2 TV is a no go as that signal is just very poor. Are there better stereo HDMI audio extractors on the market that would give an improvement?

Do you feel like the quality isn't good enough?
The digital signal should be OK and you are already using the DAC in your amplifier.
Try a slightly better HDMI extractor that only outputs optical, coax/SPDIF and i2s, but no analog. These devices cost around $50-60 and, in my experience, have no limitations. The best connection is via coax.
You could also see if you can set the HDMI output on your TV to PCM 2.0.
Incidentally, Panasonic is the largest manufacturer of all types of HDMI/transmitter chips, hence the identifier.

 

[Falco]

Do you feel like the quality isn't good enough?
The digital signal should be OK and you are already using the DAC in your amplifier.
Try a slightly better HDMI extractor that only outputs optical, coax/SPDIF and i2s, but no analog. These devices cost around $50-60 and, in my experience, have no limitations. The best connection is via coax.
You could also see if you can set the HDMI output on your TV to PCM 2.0.
Incidentally, Panasonic is the largest manufacturer of all types of HDMI/transmitter chips, hence the identifier.

Thanks for your suggestion!

Can you recommend a HDMI audio extractor? The only ones I found are with HDMI passthrough and i do not need that.

 

[Roland68]

Thanks for your suggestion!

Can you recommend a HDMI audio extractor? The only ones I found are with HDMI passthrough and i do not need that.

Before you waste money and time, check first whether the quality can be improved at all, or whether you haven't already reached the maximum.
Load a high-resolution music file (FLAC?) onto a USB stick and play it via the television on your amplifier (optical input). Then listen to the same file via PC/laptop via USB on your amplifier. If possible, at the same volume and decide for yourself whether there really is a difference.

 

[Falco]

Good advice, will do, thanks!

 

[formdissolve]

Before you waste money and time, check first whether the quality can be improved at all, or whether you haven't already reached the maximum.
Load a high-resolution music file (FLAC?) onto a USB stick and play it via the television on your amplifier (optical input). Then listen to the same file via PC/laptop via USB on your amplifier. If possible, at the same volume and decide for yourself whether there really is a difference.

The main issue that most bring up is that the optical ports on a lot of TV's are poorly implemented and max out at 16 bit/ 48Khz with a rather poor dithering implentation (at least for the random TV's I tested). I for one had major dropouts using the optical out on my TV connected to DACs with ESS chips, but it mostly works fine with AKM or other brand of DAC chips. I had the occasional dropout over optical on my C9 to my RME (AKM), and it got annoying enough where I got an Nvidia Shield Pro for streaming which allows for USB output.

As for Blu-Ray playback from my main player, I just use the secondary HDMI port on the player to output PCM to an extractor (Kanex Pro COAX) to allow for an undithered signal. I plan on upgrading to an HD Fury 4k splitter so I can plug multiple 4k sources into it and totally bypass any usage of my TV's optical port.

 

[Falco]

The main issue that most bring up is that the optical ports on a lot of TV's are poorly implemented and max out at 16 bit/ 48Khz with a rather poor dithering implentation (at least for the random TV's I tested). I for one had major dropouts using the optical out on my TV connected to DACs with ESS chips, but it mostly works fine with AKM or other brand of DAC chips. I had the occasional dropout over optical on my C9 to my RME (AKM), and it got annoying enough where I got an Nvidia Shield Pro for streaming which allows for USB output.

Indeed I had a Peachtree Audio decco65, which contains a ESS chip dac, connected to the TV. It was horrible with the constant dropouts, I actually also own a SMSL SU-1 which has a AKM4493s chip, I'll have a go if that works.
Would be interesting as I can actually connect both my Raspberry Pi streamer and my TV to the same dac then

 

[Roland68]

The main issue that most bring up is that the optical ports on a lot of TV's are poorly implemented and max out at 16 bit/ 48Khz with a rather poor dithering implentation (at least for the random TV's I tested). I for one had major dropouts using the optical out on my TV connected to DACs with ESS chips, but it mostly works fine with AKM or other brand of DAC chips. I had the occasional dropout over optical on my C9 to my RME (AKM), and it got annoying enough where I got an Nvidia Shield Pro for streaming which allows for USB output.

As for Blu-Ray playback from my main player, I just use the secondary HDMI port on the player to output PCM to an extractor (Kanex Pro COAX) to allow for an undithered signal. I plan on upgrading to an HD Fury 4k splitter so I can plug multiple 4k sources into it and totally bypass any usage of my TV's optical port.

Indeed I had a Peachtree Audio decco65, which contains a ESS chip dac, connected to the TV. It was horrible with the constant dropouts, I actually also own a SMSL SU-1 which has a AKM4493s chip, I'll have a go if that works.
Would be interesting as I can actually connect both my Raspberry Pi streamer and my TV to the same dac then

But this has nothing to do with the DAC chips used, but rather with the digital transceiver chip installed in front of it.
In the past, the AK4118 was often used, which could digest almost any signal, no matter how terrible. Unfortunately, due to the fire at AKM, the chip was not available for a long time and the manufacturers were forced to switch to other chips that were not nearly as powerful.
However, the AK4118 cannot do magic and there may be an audible loss of sound with a poor signal.
I once did the test on a TV with such a poor SPDIF/Toslink signal that 5 different DACs and even my DSC-88 service device from Sony failed. With an external AK4118 board, all devices worked perfectly and across all interfaces of the DACs (SPDIF, optical, AES, i2s), even without dropouts, but with a loss of sound compared to another source.

 

[Falco]

But this has nothing to do with the DAC chips used, but rather with the digital transceiver chip installed in front of it.
In the past, the AK4118 was often used, which could digest almost any signal, no matter how terrible. Unfortunately, due to the fire at AKM, the chip was not available for a long time and the manufacturers were forced to switch to other chips that were not nearly as powerful.
However, the AK4118 cannot do magic and there may be an audible loss of sound with a poor signal.
I once did the test on a TV with such a poor SPDIF/Toslink signal that 5 different DACs and even my DSC-88 service device from Sony failed. With an external AK4118 board, all devices worked perfectly and across all interfaces of the DACs (SPDIF, optical, AES, i2s), even without dropouts, but with a loss of sound compared to another source.

Indeed the TV toslink out signaal is extremely poor. I just want to try with the dac as i have it at hand.

As daily driver I will stick to the HDMI audio extractor arc dac which seems to work well so far.

 

[formdissolve]

But this has nothing to do with the DAC chips used, but rather with the digital transceiver chip installed in front of it.
In the past, the AK4118 was often used, which could digest almost any signal, no matter how terrible. Unfortunately, due to the fire at AKM, the chip was not available for a long time and the manufacturers were forced to switch to other chips that were not nearly as powerful.
However, the AK4118 cannot do magic and there may be an audible loss of sound with a poor signal.
I once did the test on a TV with such a poor SPDIF/Toslink signal that 5 different DACs and even my DSC-88 service device from Sony failed. With an external AK4118 board, all devices worked perfectly and across all interfaces of the DACs (SPDIF, optical, AES, i2s), even without dropouts, but with a loss of sound compared to another source.

The JDS report details the issue with ESS chips. Like I said, and as you stated above, AKM chips work fine with a lot of optical ports on TV's. I guess it's semantics now.. yes, the poor optical port and sometimes non-compliant data from the TV source causes ESS chips to constantly drop, but using AKM-based DACs alleviates that issue.

Cause: In short, the optical output of symptomatic TVs exhibit high jitter and harmonic distortion throughout the audible frequency range. The default jitter rejection values used by ESS based DACs recognize the extreme noise as signal errors, so the DAC automatically attempts a re-lock of the incoming S/PDIF signal.

This behavior is the result of the ESS's otherwise excellent jitter recovery logic. The patented jitter eliminator must periodically unlock and re-sync because the digital stream is so poor. AKM and Wolfson S/PDIF receivers are not asynchronous, so they pass along any significant jitter from an optical source, thus, eliminating any chance of a momentary pause for an S/PDIF re-locking event. Re-locks are ordinarily quite rare--you should never encounter this behavior with default jitter rejection values. And under typical circumstances, ESS's asynchronous jitter elimination results in dramatically higher jitter performance than older DACs without this technology.

 

[-Matt-]

Slightly puzzled why so many people use optical and not eARC? Is it just because you are all using stereo DACs that don't support HDMI eARC? Or are people also using optical for AVRs? I'd have though that anyone with an AVR that supports eARC should be using that connection.

...But it raises another question:
Could you also get jitter noise problems with AVR's that use ESS chips, even if the connection is via HDMI eARC?

If jitter is bad on the TV's optical port couldn't it also be bad on the HDMI eARC?

 

[Roland68]

The JDS report details the issue with ESS chips. Like I said, and as you stated above, AKM chips work fine with a lot of optical ports on TV's. I guess it's semantics now.. yes, the poor optical port and sometimes non-compliant data from the TV source causes ESS chips to constantly drop, but using AKM-based DACs alleviates that issue.

Cause: In short, the optical output of symptomatic TVs exhibit high jitter and harmonic distortion throughout the audible frequency range. The default jitter rejection values used by ESS based DACs recognize the extreme noise as signal errors, so the DAC automatically attempts a re-lock of the incoming S/PDIF signal.

This behavior is the result of the ESS's otherwise excellent jitter recovery logic. The patented jitter eliminator must periodically unlock and re-sync because the digital stream is so poor. AKM and Wolfson S/PDIF receivers are not asynchronous, so they pass along any significant jitter from an optical source, thus, eliminating any chance of a momentary pause for an S/PDIF re-locking event. Re-locks are ordinarily quite rare--you should never encounter this behavior with default jitter rejection values. And under typical circumstances, ESS's asynchronous jitter elimination results in dramatically higher jitter performance than older DACs without this technology.

The problem generally occurs with SPDIF (RCA) and optical connections. It is only partly due to poor signal quality and largely (especially with 2 major manufacturers) due to the fact that the signal does not comply with the SPDIF standard. This is because other information is also transmitted that the soundbars from these manufacturers and all AVRs have no problems with, but most normal/high-quality DACs that only understand standard SPDIF cannot cope with.
Either the JDS is not known, or they interpret everything that does not correspond to the standard SPDIF signal as jitter/dirt. Which is absolutely correct.
For these reasons, there are almost no problems with the old DACs with AK4118 (or 4113). Only after the fire at AKM did the problems increase because other ICs had to be used.
And to emphasize it again, the fact that the AK4118 works between the TV and the DAC is a personal experience with more than 10 TVs from the two major manufacturers.

Doesn't it make you think that the soundbars on these TVs work perfectly, with surround functionality?

 

[Roland68]

Slightly puzzled why so many people use optical and not eARC? Is it just because you are all using stereo DACs that don't support HDMI eARC? Or are people also using optical for AVRs? I'd have though that anyone with an AVR that supports eARC should be using that connection.

...But it raises another question:
Could you also get jitter noise problems with AVR's that use ESS chips, even if the connection is via HDMI eARC?

If jitter is bad on the TV's optical port couldn't it also be bad on the HDMI eARC?

As already mentioned several times, this is not a problem with the DAC ICs, but, in most cases, with the additional and non-standard information transferred. That's why there are hardly any problems with AVRs and soundbars, only with stereo DACs.
Stereo DACs very rarely have an HDMI connection for the television. Which isn't a problem at all, as long as signals that comply with the standard are available.

 

[-Matt-]

As already mentioned several times, this is not a problem with the DAC ICs, but, in most cases, with the additional and non-standard information transferred. That's why there are hardly any problems with AVRs and soundbars, only with stereo DACs.

You sound exasperated!

I skimmed the whole thread (not the external site) and this seems to be the first time that "additional and non-standard information" over the optical connection has been mentioned. It could explain a lot. The previous posts only seem to mention jitter (on the tv's digital audio output).

Throughout the thread it has been clear that we have been discussing that the jitter handling of ESS DAC chips can struggle if the jitter level from the attached device is too high (or as you now say, if the signal is corrupted with additional non-standard information). Whether you blame the DAC or the attached device seems a bit irrelevant (it is a mutual incompatibility) and my post certainly wasn't pointing the finger at the DAC ICs, as you seem to imply:

As already mentioned several times, this is not a problem with the DAC ICs, but, in most cases, with the additional and non-standard information transferred. That's why there are hardly any problems with AVRs and soundbars, only with stereo DACs.

@wyup seems to report that there are also problems via HDMI ARC:

On what do you base that eARC from TV is more reliable than optical? Both are clocked fron the same device, the tv. I tested both, and the tv resamples 44.1Khz to 48KHz the same, and in my case It had dropouts aswell on HDMI arc. It all depends on the dac's ability to reduce jitter.
My solution was using a Raspberry Pi with a spdif transport with good clocks as a streamer for A/V. It respects original samplerate and sounds better.

I'd like to know for sure if this was ARC or if eARC was also tested?

Problems with AVRs could be less frequent because fewer people are using them than soundbars and stereo DACs, and within that subset relatively few AVRs use ESS chips. Which is why I specifically asked:

Could you also get jitter noise problems with AVR's that use ESS chips, even if the connection is via HDMI eARC?

Just because there may be fewer of us doesn't make it invalid to ask:

If jitter is bad on the TV's optical port couldn't it also be bad on the HDMI eARC?

which seems to be supported by @wyup 's observation.

So, if the problem is actually due to additional information getting sent over optical that isn't standard for SPDIF can you categorically state that this problem can't also apply to HDMI eARC? If so, how do you explain the problems that @wyup observed?

I'm trying to work out if there is any sense in attempting to circumvent eARC between my LG OLED and ESS DAC'd AVR.

 

[Roland68]

You sound exasperated!

I skimmed the whole thread (not the external site) and this seems to be the first time that "additional and non-standard information" over the optical connection has been mentioned. It could explain a lot. The previous posts only seem to mention jitter (on the tv's digital audio output).

Throughout the thread it has been clear that we have been discussing that the jitter handling of ESS DAC chips can struggle if the jitter level from the attached device is too high (or as you now say, if the signal is corrupted with additional non-standard information). Whether you blame the DAC or the attached device seems a bit irrelevant (it is a mutual incompatibility) and my post certainly wasn't pointing the finger at the DAC ICs, as you seem to imply:

You're interpreting something into that. The problem has generally been described several times on ASR.
But maybe a few facts will make things clearer.
- SPDIF (RCA), Toslink/optical and AES are the same signal only on different transmission media, which are generated from i2s and are converted back into i2s before or in the DAC chip.
- The proportion of dedicated stereo DACs over $100 that are connected to TV sets is negligible compared to soundbars and AVRs. This also explains the extremely low proportion of DACs with HDMI interfaces on the market, as it is an absolute niche product. (Future all-in-one chips could also integrate HDMI here).
- That's exactly why TV manufacturers don't care at all about 100% compatibility with the SPDIF standard, and therefore also with the 2-channel DACs. It's simply not a relevant market.
- I have checked over 10 different TV sets and more than 10 different current DACs that had problems with the Sony DSC-88. The DSC-88 couldn't do anything with the TV's SPDIF signal, but all DACs worked perfectly on the DSC-88 and without any dropouts. The Sony Digital Signal Checker was developed by one of the two SPDIF developers as a workshop device, anything that doesn't work doesn't meet the standard, poor signal quality or not.
- All of these televisions, which only came from 2 major manufacturers, run smoothly via SPDIF on various AVRs and with an external AK4118 board also on 2 channel DACs. For me, this rules out a bad SPDIF signal as the sole cause. Of course, this only applies to my personal experience.

Leave the 2-channel DACs aside and research problems with TVs and digital audio output worldwide. You will quickly realize that there are profound problems that are not only related to the hardware, but also to firmware revisions, apps, sources, transmitters/channels, etc. There are different outputs on the same device depending on what app is used, channels, cable or streaming, etc. These issues affect HDMI and SPDIF.

Three more interesting pieces of information.
- With a DAC that only understands standard SPDIF, any additional information in the SPDIF signal will result in jitter. In extreme cases the signal is unusable.
- Almost everyone who is affected by this problem with their television and 2 channel DAC sees the problem with the DAC manufacturer.
- Some AVRs can also output the SPDIF signal from the TV digitally as SPDIF. Connected to the output, the 2 channel DAC also worked perfectly, but again connected directly to the TV it didn't work.

Everyone can form their own opinion about it.

 

[-Matt-]

When was the DSC-88 manufactured or updated last?

S/PDIF as described in IEC 61937 has been continually updated to include new encoding formats. Most recent update that I can see is July 2021.

Perhaps the DSC-88 is no longer compatible with the most recent S/PDIF standard?

 

[Roland68]

When was the DSC-88 manufactured or updated last?

S/PDIF as described in IEC 61937 has been continually updated to include new encoding formats. Most recent update that I can see is July 2021.

Perhaps the DSC-88 is no longer compatible with the most recent S/PDIF standard?

And that's exactly where it gets not just warm, but really hot.
Of course, the DSC-88 doesn't comply with the latest SPDIF standards, and that's exactly what it's not supposed to do. This is only about stereo (2-channel, not 2.1) standard SPDIF.
The standard was only expanded, not changed, because that would be fatal for any compatibility.
Tens of thousands or millions of devices that work with this standard in the professional audio sector with device generations well over 30 years apart with virtually no problem, but the really big TV manufacturers can't manage this data output?

A few months ago I took a few different generations of DACs into a recording studio. The oldest, a Cambridge Audio DacMagic-1 from 1994 with TDA1305, and the newest an SMSL SU-10 from 2023. The studio is equipped with multi-channel technology, but all DACs ran without any problems on the digital sources set to stereo. Nobody expected anything else.

I would be interested to know whether it is simply ignorance/ignorance on the part of the TV manufacturers, or whether there is a certain calculation in favor of in-house soundbars and surround devices. But we'll never know.
On the other hand, it shows that for most of us, including the audiophile community, the TV is valued like a sacred cow, because the DAC is the culprit for most of them.

My Chiq 55" 4K UHD, which is now over 6 years old and is very inexpensive, has an SPDIF/RCA output that can be set to PCM Stereo in the menu. To the chagrin of several friends, every DAC runs without any problems, an E30 as well as my DacMagic-1 or my Sabaj A30a.

 

[elvisizer]

I'm trying to work out if there is any sense in attempting to circumvent eARC between my LG OLED and ESS DAC'd AVR.

if eARC works for you and your dac/avr/whatever+tv aren't having dropouts there's no reason to make any changes.
if you're having dropouts, then try a different connection method.