OT - home cinema question

Flame Tools and Tech
1

Just wanted to throw this out to see if anyone knows what’s happening!

Bought myself a new LG C1 oled and sound bar just before Christmas…and after being really underwhelmed by the soundbar bought the extra Bluetooth rear speaker kit. Blown away by what a difference these have made to the sound.
My question …i have not had a tv sound system capable of handling Dolby Atmos and dtx before, and on many shows that use these i am hearing some really annoying artefacts…either a lot of crunchy, crackling sounds during conversations, and at other times something that sounds like an automatic noise gate during gaps between sentences.
If it wasn’t for the fact these are big shows with proper sound mix facilities i would assume it was pisspoor audio editing, but i don’t believe that.
Weirdly, some shows sound fantastic and display none of this stuff.

I have checked all the possible settings and nothing seems out of place (disengaged auto levels etc)

Anyone know what might be going on?

2

I thought perhaps a loose cable, but I asked our in-house audio enthusiast:

"Sounds more like a decoding problem to me. With a bad (or loose) cable I’d expect to see video glitches as well, since video requires much higher bandwidth than audio, and flaky video signal would interfere with HDCP (copy protection). But it’s very easy to swap or reseat cables, so it can’t hurt to try.

This reminds me of a problem we had years ago, when the streaming services started dropping the audio bitrate to save bandwidth, and my fancy processor was having trouble dealing with the low-quality audio stream. As though the manufacturer never tested extremely low bitrate DD+ because “who would ever do such a thing”. I’ll tell you who–Netflix.

Maybe the soundbar can’t process Atmos or DTS:X very well even if it was advertised to do so. He could try disabling the spatial audio formats and just using traditional 5.1 lossless formats (DTS-HD and Dolby TrueHD). If that works consistency, then problem identified.

Maybe it’s the streaming app. Is he using the built-in apps on the LG TV or a standalone box like an AppleTV or Roku? I’ve only ever used AppleTV and it has worked well.

Maybe it’s streaming, period. Does he have any audio problems playing back a Blu-ray or UHD Blu-ray disc?

Speaking of audio quality, bluetooth has only a small fraction of the bandwidth of any lossless surround sound format. The audio being sent to those bluetooth surrounds is definitely being recompressed. Maybe that’s part of the problem.

In general I’m no fan of soundbars, and I’m certainly no fan of bluetooth for anything resembling “quality”. I’m not convinced there is much utility in decoding spatial audio formats (Atmos, DTS:X) if you don’t have height and/or ceiling. If constrained by space and/or budget, and you can’t do more than 5.1 (or possibly 5.0 in this case, I don’t know if he has a sub), I would personally build a 3.0 system. That is, front/center/left speakers, with a decent receiver and decent separate speakers. E.g, mid-range Denon or Integra receiver, maybe something like PSB Alpha speakers. And if there still is room in the budget, again for me personally, I would put any extra money into speakers. E.g. entry-level B&W or Dali. If sound quality is paramount, then speakers are the most important component IMHO."

4 Likes
3

If you are watching streaming content on it, it is not a fair form of judgement.
There are way more variables thrown into the equation than its worth.

1 Like
4

i have a feeling it’s probably down to the streaming services. I have noticed big differences between the built in apps and those on the apple tv box showing the exact same content.
The rear speakers are not the issue - its the front audio - specifically dialogue. Its definitely not lose cable kind of crackle, its more specific to the dialogue frequencies which makes me suspect its some for of compression artefact.
It’ll do for now…just wanted to see what others thought might be the cause. Certainly throwing any more cash at it!

thanks

5

Random question; does the sound artifact you’re hearing sound “slushy”? I’m not sure how else to describe it but sort of a Daffy Duck speech impediment sound, like ‘sshllhsllshh’ - and it comes and goes?

6

Not really, more like someone is moving boxes around offset during the take…and occasionally eating crisps while they are doing so!

7

Well that also could make sense based on what I was trying to describe :smiley:

I ask because I had an issue with an old Denon receiver and Dolby Digital Plus content (for me, Amazon Prime, I don’t have Netflix as banshee alluded to it above but same thing) where stuff would just sound horrible. It wasn’t constant, it came and went based on the content. Anyway, it turns out this was a known issue with the DD+ decoder and it affected many products across many vendors. Unfortunately my particular receiver didn’t have upgradable firmware and ultimately I wound up buying a newer one which fixed the bug.

I don’t know if what you’re hearing is necessarily this particular problem, but that’s why I was asking because there is a definite problem specifically with certain Dolby Digital Plus decoders. I wish I still had the video on my phone I recorded of the sound of it.

8

/furiously taking notes.

2 Likes
9

Interesting…it seems to be mainly on Amazon Prime.
Difficult to make specific tests …if i mention it, then my wife will focus in on it and never hear anything else! Gives me a good direction to investigate further!

10

Some of the best sound i have is occasionally connecting my Bang &Olufsen speakers to a digital preamp via the optical output. Those two speakers give an amazing sound…its just an over the top extravagance to switch it all on and then have to get up to adjust the volume on every other show. Very lazy, i know.

11

FWIW I have a Sonos ARC with 2 of the Ikea Sonos speakers as rear surrounds and I think it’s great. I used to use my turntable setup (KEF bookshelf 2-ways and Yamaha amp) to double as my TV sound and the Sonos is way better. And cheaper. And it just works.

I didn’t expect to care about the Atmos/surround aspect of it but I’ve been really surprised by how much it shows up in the bigger budget sci fi shows like Foundation on Apple and Cowboy Bebop on Netflix

1 Like
12

Cowboy Bebop did sound great on this setup.