LG says optical output is fussy. Are they right?

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worksong

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A new 65” LG has sound output settings that include this one: “internal speakers + optical audio out.”

The internal speakers work fine.

My headphones with D/A converter, fed from the optical port, work fine when just “optical out” is selected.

> On the combined setting, the internal speakers work but the headphones don't.

LG claims it’s because I’m using a D/A converter, & says the combination setting works fine when they connect an optical input soundbar.

I say the TV can’t know what optical device is connected, & an optical output is either on or off.

Is LG right or wrong?
 
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You are right that the TV doesn't know what is connected to the optical output.
They may be right if the DAC you are using is not compatible with a 5.1 input which their soundbar would be. Why the optical out should change to 5.1 when you select the combined setting is strange. LG may have a technical reason for this or they just made an assumption about how you would use the TV. Some TVs don't allow combined optical and speakers at the same time.
You are right that the TV doesn't know what is connected to the optical output.
They may be right if the DAC you are using is not compatible with a 5.1 input which their soundbar would be. Why the optical out should change to 5.1 when you select the combined setting is strange. LG may have a technical reason for this or they just made an assumption about how you would use the TV. Some TVs don't allow combined optical and speakers at the same time.
 
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worksong

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I don't know yet if americanaudiophile is right...but seems highly likely:

I borrowed a set of headphones that are Dolby/DTS capable. These work on the optical only setting, & also on the optical + internal speakers setting. However, while listening to an olympics broadcast on the combined setting, as they switched between commentators & various venues some signal channels I could hear on the TV speakers simply disappeared from the headphones, while other signals remained audible. In some cases, I was hearing background venue music but not the commentator doing interviews. The "5.1 only" theory seems plausible.

For LG to force this operating mode is a questionable design decision; for them to leave it completely undocumented [Craig @ LG-USA QA has no idea how it's supposed to work, & is making his best guess] is just dumb.
 

worksong

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You're right; sorry.

TV: LG 65UH615A

DAC: PROZOR DAC Digital SPDIF Toslink to Analog Converter Adapter

phones [optical]: Sony MDR DS3000 [aka DP IF3000]
 

budwich

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well based on a quick scan of the user guides and the "limited" info that you posted about the problem, my guess is that your prozors can only handle PCM coming at them so to ensure that is what you get, you need to set the sound mode... oops... digital output mode.... to PCM and NOT AUTO. Again, best first guess.

Further, your "description" of the "other headset" (ie. dolby/dts) doesn't indicate what they are or how they were connected... likely not by way of your prozors.... hence that "box" can likely handle more incoming signal types hence your "findings". BUT I would point out that it indicates this in the manual.

Anyways, good luck... I think your system will work fine once you get to the right settings.

Further, "5.1 headsets" aren't always a good "choice" with a tv signal as the "mixers" aren't always that great in terms of where certain "voicing/sounds" come from or are positioned.... they maybe able to be set to "stereo" to stop the "sound stage wondering".
 

worksong

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Thanks, budwich. To clarify:

The phones plugged into the PROZOR are KLEER analog [that's why I need the DAC]. I hooked up the Sony phones because they have a TOSLINK input & let me test the TV output without the converter.

Keep in mind that LG techs are saying the DAC is the problem.

The real issue here is that sound mode on the LG can't be set manually. Users can only select 1 of 4 preset output combinations. Best guess [I have no way to measure] is that when "optical out" is selected, the TV sends 2.0, but when "internal speakers + optical out" is selected, it sends 5.1...which I know the DAC won't handle.

If I'm right, the TV needs a firmware update to remedy.
 

budwich

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I think the manual is pretty specific, you need to set the digital output mode to PCM. The setting for the "ports" of output is something different. Make sure you are going thru the right "branches" of the "menu" system.
 

worksong

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Budwich--you nailed it. I was focused on the ports & missed the mode setting menu; should have done that 1st.

Hard to understand why LG techs didn't simply point there...but that's a different problem.

It's working now--many thanks!
 

budwich

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well, they are only as good as the information they get. Did you mention that your "unit" only supports PCM in? As you see from this thread, if "incomplete information" is provided, the outcomes can greatly vary from good to bad. Even with my initial "suggestion", you were still questioning about the system not being able to do something. Glad it works now, good listening.
 

worksong

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Yes, I did. And I answered every question the techs asked during the 40 minute call. They never asked about, or suggested checking, the settings on that segment of the menu.
 
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