I've a strange issue that I've been struggling for a week. I bought an LG43UJ634V UHD TV and an LG LHB645N Home Theater in a Box system.
I use HDMI ARC to connect the audio from the TV to receiver. LG has an option to chose between PCM or Auto at the Digital output settings.
If I use the PCM option everything sounds great, but I don't have 5.1, only 2.1.
And here comes the problem. When I choose Auto, 5.1 is on, sounds great but I have occasional popping noise (like when play something on an old LP player) it happens random, but for example during a film, it is very annoying. It happens with YouTube, Netflix, DLNA streaming, external devices, so the content doesn't matter. I think I've tried everything. I tested it with different HDMI cables, optical cable, but still have the problem. I tested it with a sound bar as well, the problem is the same.
When I play content from the receiver, there is no problem, the sound is wonderful, no popping. Also, the TVs speakers are okay.
I don't think it is a hardware issue, because the TV's sound is OK, the home theater's sound is OK, the problem only happens when I want to use the digital output of the TV (either HDMI ARC or Optical) with auto setting.
I called LG as well, the rep. said the she will pass this info to the technical team.
Do you have any idea, that it can be solved, or I need to wait for a software update?
I have a 55LJ550M (WebOS 3.5) TV, connected to an A/V Receiver via ARC.
Per the online documentation, when the TV encounters AAC audio, it will transcode that audio to Dolby Digital for transmission over ARC. See: http://www.lg.com/ca_en/support/product-help/CT20098005-1437136302910-others
However, the sound quality is very poor when this occurs. The sound is full of compression artifacts, and with some older A/V Receivers, this causes the sound to periodically cut-out.
Some of the WebOS applications affected by this issue are YouTube (which mostly uses AAC audio), any Netflix stereo programming, and using the Music\Photo\Video app to play music or videos with AAC audio. To me, it makes the entire YouTube application unusable.
Honestly, I'm surprised that WebOS doesn't just output PCM audio over ARC whenever it encounters AAC. This would make more sense, and it would require less processing power and sound much better. (I know that I can set the TV to output everything to PCM over ARC, but I do not want to lose DD 5.1 and DTS sound from other programming which works perfectly).
Is this behavior a known WebOS 3.5 issue? I know that my unit is a one of the cheaper LG sets--it is possible that this particular set is just too under-powered to function as designed?