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Noisy digital audio on LG TVs

silverfalcon

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@wyup I assumed (wrongly) that optical was an old standard and the firmware for resampling may be different (and better) with a new standard like eArc. That is a bummer becasue I was about to get the Bluesound Node X which has the ESS 9028Q2M Sabre DAC. From what I've read, ESS Sabre has even less tolerance to jitter and it is possible that the LG G3 + Node X combination might not work at all?

EDIT: Does your Raspberry Pi solution work as an effective TV out to Speakers setup?
 

wyup

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ESS Sabre jitter reduction is good, but depends on its implementation. I have Aune X8 XVIII dac, which has not much tolerance. It is FPGA based but It also has ESS 9038QM chip. Some 9038QM based dacs have better jitter rejection.

Yes, my RPI4 with Kodi Libreelec and tv hat can decode DVB tv, because my Samsung TV produces dropouts on optical mainly with tv antena. But my TV hat was defective and I couldn't test It. I solved tv optical dropouts to the Aune by connecting to TV by USB port and It works!

Recently I bought another tv hat but I haven't got to try it. The audio quality difference is small. Optical and USB from tv sound different as well. My Ian Canada Transport PiDigi sounds a bit better than both. It is subtle (more resolution). Optical from tv sounds good as well, if it were not for the dropouts. DVB sound is low res, but movies sound better with the streamer, as does youtube (I did live switching). You need a good amplifier, dac and speakers to appreciate the difference nuance between inputs, but there sure is. You hit your gear limits easily. I have realized the amplifier is the most important element that limits sound quality. You can have the best dac but if your amp is bad you won't hear it's resolution.

I wanted a device that respected music files original 44.1 Khz sampling rate instead of 48 Khz resampling as the tv does. And even if you have jitter reduction built-in in the dac as Amir jitter tests show, me as for one, I prefer better clocked signal than having to dejitter it, because jitter correction also introduces noise. I realise in the end that the difference is subtle. I don't have good enough equipment to proper evaluation. A/B tests give me headache. Different digital inputs sound different: optical has more bass and midrange body that seem better quality, but I don't know if its rounding-up or not. It sounds like different eq presets. But Coax from RPi Digi Streamer seem to sound the best, detail-wise. I will tell you when I have a better amplifier and dac aswell. But I rest assured that my spidif transport is not limiting me. I hate the tv resampling my audio collection (or spotify app). And the tv has a lot of jitter, the proof is it produces dropouts with my dac that other digital sources don't. I also must confess that My Onkyo amp internal dac doesn't produce dropouts with my present tv. But it is inferior quality to the Aune X8.
 
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pablolie

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ESS Sabre jitter reduction is good, but depends on its implementation. I have Aune X8 XVIII dac, which has not much tolerance. It is FPGA based but It also has ESS 9038QM chip. Some 9038QM based dacs have better jitter rejection.

Yes, my RPI4 with Kodi Libreelec and tv hat can decode DVB tv, because my Samsung TV produces dropouts on optical mainly with tv antena. But my TV hat was defective and I couldn't test It. I solved tv optical dropouts to the Aune by connecting to TV by USB port and It works!

Recently I bought another tv hat but I haven't got to try it. The audio quality difference is small. Optical and USB from tv sound different as well. My Ian Canada Transport PiDigi sounds a bit better than both. It is subtle (more resolution). Optical from tv sounds good as well, if it were not for the dropouts. DVB sound is low res, but movies sound better with the streamer, as does youtube (I did live switching). You need a good amplifier, dac and speakers to appreciate the difference nuance between inputs, but there sure is. You hit your gear limits easily. I have realized the amplifier is the most important element that limits sound quality. You can have the best dac but if your amp is bad you won't hear it's resolution. I bought a Hypex NC122MP 75w class D based amp that sounds coarser than my previous cheaper Onkyo A-9010, although more powerful. It wasn't until I replaced the Onkyo that I noticed better DAC and transport sound.

I have never used the built-in speakers on my TV. I do remember doing a test many years ago to test the optical Toslink quality. I recorded a FLAC file to CD-R, played it through the TV, recorded a new CD-R with the output, compared the files... and the files were identical. So while I don't doubt some the "A" in "DAC" can produce digital results, I think my test make it reasonable to assume that -in my case- the Toslink output on my 14 year old TV is transparent. Mind you, it was worth around $4k back in the day, so it better be well-engineered. And comparing it with newer TVs, I am still entirely happy with the picture quality (no 4k, though, just good ole 1080HD). I am not much of a video aficionado though.
 

lennyanders

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My required solution is quite similar to yours. These days TV UIs are very good and I want to be able to play music videos and content from my TV but with higher resolution. The Bluesound seems to be the perfect solution especially since Optical does not seem that reliable from the LG tvs anyways and hopefully the eARC works reliably in terms of dropouts and in terms of sampling rate from the TV/source. Also, I was looking for a streaming player as well and this one of the very few players that seems to support HDMI eArc. Do you also have an LG? I am hoping it works reliably over HDMI eARC but we will see
Yeah, I have the LG BX though. So the cheapest OLED from about 3 years ago from them. I like the streaming ability of the BlueSound Node too, I use Spotify connect sometimes and it works great.

I read that you want to use the analog output though, I only use digital, so I can't really comment on the quality of that. I read it's worse or even pretty bad for the price, but probably still inaudible, and you could later connect a better DAC if you wanted.
 

ban25

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Yeah, I have the LG BX though. So the cheapest OLED from about 3 years ago from them. I like the streaming ability of the BlueSound Node too, I use Spotify connect sometimes and it works great.

I read that you want to use the analog output though, I only use digital, so I can't really comment on the quality of that. I read it's worse or even pretty bad for the price, but probably still inaudible, and you could later connect a better DAC if you wanted.
You are confusing the Node X for a different product. I haven't seen any measurements of the ESS 9028Q2M-based Node X.
 

formdissolve

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pablolie

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That is the reason I want to make a 3.1 system so I can have a dedicated center channel for audio. I don't have the room for 5.1/7.1
I have no issues with dialogue other than with today's actors often having zero real theater background and whispering or being inconsistent with their voice tone/enunciation. And I have a good old-fashioned stereo setup - admittedly a lot of setup work went into finding the optimal toe-in etc for my seating position, and when there are more that a few other people watching with me they may not be as lucky...
 

formdissolve

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I have no issues with dialogue other than with today's actors often having zero real theater background and whispering or being inconsistent with their voice tone/enunciation. And I have a good old-fashioned stereo setup - admittedly a lot of setup work went into finding the optimal toe-in etc for my seating position, and when there are more that a few other people watching with me they may not be as lucky...
The issue for me is that it's re-mixing the 5.1 into 2.0 which takes any audio from the center channel and splits it 50/50, then dumps all the rear audio into the stream (usually kind of poorly in the TV), which makes it fairly muddy on my system, especially because a lot of dialogue these days is mixed lower than music/sound effects tracks.

Some of the streaming services offer native 2 channel audio options in the US and that helps dialogue on my system. I think in Europe it's mandated that a 2 channel PCM track exists on services, which would be awesome. I use an HDMI extractor for 2 channel for blu-ray and the conversion is much better.
 

Greenman

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I currently use digital optical from my LG C1 to an old Denon AVR and have had no issues whatsoever. The AVR decodes the audio and powers the centre and surround channels and provides preouts for the front L and R channels. I’ve always done things this way with two prior TVs and never had issues. This is much simpler than feeding each tv source to the AVR separately, and in the case of the internal tuner and the connected Firestick couldn’t be done that way anyway.
 

r042wal

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I just purchased an LG 65" 4K OLED TV. I have not wired it into my sound system yet. I use the Toslink to my Mc preamp, TV, HDMI (1) for my Amazon Fire Cube and HDMI (2) for my local cable TV box.

I am totaly isoloated from my gear at at the moment. As a matter of fact, all my gear is uplugged from the wall except my sub. As soon as I plugged my CAT6 cable into my LG, I got really bad 60Hz hum on my SB-2000 Pro sub. Not sure why.
 

formdissolve

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I just purchased an LG 65" 4K OLED TV. I have not wired it into my sound system yet. I use the Toslink to my Mc preamp, TV, HDMI (1) for my Amazon Fire Cube and HDMI (2) for my local cable TV box.

I am totaly isoloated from my gear at at the moment. As a matter of fact, all my gear is uplugged from the wall except my sub. As soon as I plugged my CAT6 cable into my LG, I got really bad 60Hz hum on my SB-2000 Pro sub. Not sure why.
@r042wal does your Cat6 cable have metal tips? There could be some ground issue. Also, any reason why you want to use ethernet? No WiFi?
 

r042wal

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@r042wal does your Cat6 cable have metal tips? There could be some ground issue. Also, any reason why you want to use ethernet? No WiFi?
Not really. I will try disconnecting the Ethernet and see what happens. Thanks
 

formdissolve

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Not really. I will try disconnecting the Ethernet and see what happens. Thanks
Ah, your previous post said you noticed the 60hz hum when the ethernet cable was plugged in. If that's the case, you may as well just WiFi.
 

soundwave76

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I have the C1 but never noticed any issues with it, since I have been using the Bluesound Node from day one. Optical to Bluesound and then coax to Genelecs.
 

Smoey22

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I'm once again reviving this topic due to it inherently being a cluster of parameters to optimize, we are talking bitstream, PCM, change format, passthrough, multi-channel, Atmos etc.
Decided not to create a new thread as I don't want to fragment the topic any further.

I've been using the LG TV's native S/PDIF port up until recently (see attached schematic, option 3). Worth mentioning that I've not experienced any dropouts with SMSL DO300 (ES9039MSPRO), neither from the native LG TV S/PDIF port nor the new extractor/switch, as a consequence the DPLL setting is set to 1 without issue. After reading this thread I decided to buy and experiment with an HDMI extractor & eARC/ARC switch from AliExpress. Bought it hoping it would perform as well as similar HDMI extractors reviewed by @amirm (Amazon Basics 4K HDMI Extractor Review and Monoprice Blackbird Review).

I would appreciate feedback on how to optimize my setup in regard to sound quality. I'm primarily using Apple TV for Netflix and HBO, for critical listening I connect the DAC with USB to a PC (Roon).

After some tweaking I'm torn between extracting the audio signal from HDMI (option 1) or from eARC/ARC (option 2). The former circumvents the TV, the latter more connectivity user friendly. With eARC I get the "Atmos"-symbol in Netflix, with ARC it is PCM 2Ch 48 kHz. The extractor/switch is set to 2.0Ch for both cases.
Can Atmos be downsampled to 2.0, and how does it compare to PCM 2.0?

Optimize for psychoacoustics they said, it'll be fun they said..
 

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Tre2023

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The Apple TV 4K will convert all signals to LPCM for output when audio is set to Best Available and Atmos metadata will be retained for Dolby Atmos tracks. With PCM 2.0 going into the stereo amplifier via optical cable, the conversion may as well take place in the Apple TV 4K to start by setting audio output to Stereo.

With the Apple TV 4K set for Stereo output, the TV HDMI ports can be set to bitstream and the Digital Audio Output setting set to Passthrough with eARC Support ON. This way, the TV simply passes the signal along without any tampering of it as it makes it’s way to the extractor.

But, with the Apple TV 4K and LG TV set up in this way, the extractor really isn’t necessary and an optical connection directly to the stereo amplifier from the TV would suffice. Converting audio at the source device is preferable to any processing by the TV as sync issues can arise as the TV processes audio and video depending on the settings for both picture and sound.
 

wyup

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Nice schematics :)

I think that if you don't have dropouts using toslink from the LG TV straight to your dac at DLL 1, that is the most straight connection for your TV.
For your Apple TV streamer I'd connect to the dac using coaxial, and switching inputs from the dac. It's not worth passing through the tv by HDMI because the tv is going to reclock it. That's how I do with my RPI streamer.

Another option that might work is connecting your LG by usb to the dac, as a PC. It works with my Samsung Oled tv and does control the volume.

I'd avoid using hdmi or earc extractors. I tried one once and they work, but they have their own clocks. HDMi uses different muxing frequency than spdif, which is native.
 
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bboris77

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Here’s an update from JDS Labs confirming that the performance of the optical output of their LG TV is not quite as disastrous as originally thought. They repeated the test while using 16-bit 48kHz and the SINAD was 95dB. Still quite low in the current day and age, but potentially inaudible unless your DAC drops the signal.

What is quite disappointing is the lack of transparency and response on the part of these TV manufacturers. It would be really interesting to know whether the more recent LG Oleds have an improved performance.

 
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