AVR setup/help

[guiltysoul]

(Note: turned out longer than expected, TLDR at bottom)

Hello,

Firstly, I should say I'm a complete noob in this department and I'm sorry if any of my questions are basic/stupid. Also sorry if this is in the wrong place.

I bought my first AV receiver about a week ago and after setting it up and playing around with it I have a few questions I hope you guys can help with. I've tried googling around but it's just leaving me more confused.

The system in question is the LG SR906 (LG SR906SB Home Cinema System - LG SR906SB 5.1Ch 3D signal pass through receiver system - LG Electronics UK), I have my PC (HD7870) and PS3(slim) connected via HDMI to the receiver and the receiver to a BenQ EW2430 (EW2430 - LCD Monitors - Products | BenQ Global).


1. Regarding the games on PS3.
As I understand it PCM mode on the receiver is the best option as it provides lossless audio? My problem is, certain games won't output 5.1 audio unless I mess with the options and get it to output in either DD or DTS.

So I am wondering if I should just change the settings to force DD/DTS 5.1 on games that won't output 5.1PCM and change the settings back when I want to play a game that does support 5.1pcm. Is the difference in sound quality THAT huge? As I haven't really noticed it (but I'm also wondering if that is due to incorrect set up). What I mean by this is in games that support both options, the surround sound seems to work, like if I spin around the audio moves around the speakers, I'm just not sure of a difference in quality. Or should I just play all my games in DD/DTS


2. Regarding BluRays on PS3.
This relates to the gaming issue slightly. If I have my PS3 configured to output PCM 5.1 as well as DD/DTS 5.1, then in movies I have the option for both depending on wether I set Bitstream or LPCM, so I am wondering is this just the same as the solution above, switch the settings as necessary since LPCM is superior.

Also, something that slightly confuses me here is none of my BluRays say they support LPCM 5.1 or anything, it only says things like DTS, DTS-HD on the back of the case, does this mean they actually do not, and playing the movies with LPCM is irrelevant? Or is LPCM allowing my receiver to play the DTS-HD audio instead of regular DTS?


3. Playing DVD's on PC

When playing DVD's on my PC I can't notice a difference in audio quality between PCM and DD, PCM just seems louder. I'm assuming this is because there is no HD audio track on a dvd and a HD audio track is where PCM outshines DD? Please correct me if this is wrong.


4. Playing downloaded movies on PC/VLC media player

When playing a file (e.g. .mkv) on VLC when I go to Audio > Audio Device I have the choice of selecting 5.1 or a/52 over S/PDIF. When selecting the latter audio will output in DD or DTS 5.1 depending on the file. When I select 5.1 the audio comes out as 5.1 PCM. However the PCM sounds a fair bit worse, it's much louder and the vocals are not as clean, almost sounding distorted.

What confuses me is everything is connected by HDMI, so why is it offering a optical option, and why does that output DD/DTS. What REALLY confuses me is why the PCM sounds alot worse.


5. Gaming on PC

When playing games on PC, no matter what I do the only option available is PCM, I haven't been able to find a way to force DD or DTS 5.1. This seems to leave me at the mercy of each specific game as to wether I can get any 5.1 sound at all. Games with no setting in the options menu to adjust the speaker set up will leave me with only stereo audio, games that do have the setting allows me to get 5.1. For example, Counter Strike: GO allows me to set 5.1 as does StarCraft 2, Bioshock Infinite and Remember Me have no such options and only allow me 2.1 or 2.0 audio even though my receiver will show PCM with all of the speaker options lit up. I'm at a loss for a solution here so hopefully you guys can provide some insight.

Thank you for taking the time to read and I really appreciate any information you guys can prodive on my issues.


TL: DR

Taking into account my set up/ receiver:
1 PCM or DD/DTS when gaming on PS3?
2 Bitstream or LPCM when watching BluRays on PS3?
3 No difference between PCM and DD/DTS when watching DVDs on PC?
4 .mkv audio sounds worse through PCM than DD/DTS on PC/VLC media player.
5 Certain PC games only output 2.1 audio, never allow DD/DTS or 5.1.

 

[Grador]

Answering from the TL: DR so if I'm not covering something adequately feel free to ask for clarification.
1. Irrelevant. Your receiver will be decoding DD/DTS to PCM itself if you send it DD/DTS, so either way the receiver is going to end up with the same PCM.
2. Same as above.
3. Same as above with a note below
4. MKV files are a container and does not specify audio type (it could be mp3, aac, DD, etc etc). If you don't have your system set up right on how it outputs PCM then DD/DTS will sound better.
5. Only certain games output DD/DTS audio, so this makes sense. Keep in mind also that DD does not mean surround sound, it is simply a means of encoding audio. Games that output DD are actually doing an extra step of ENCODING into DD before sending the sound off to the sound card. Using HDMI this step is now pretty pointless, it's main utility was for hooking things up with optical where you couldn't send uncompressed 5.1 PCM. With HDMI you can send 7.1 PCM no problem, so compressing into DD first is just wasteful.

 

[guiltysoul]

So regardless of whether my receiver displays PCM, DD or DTS the audio is coming out as PCM?

For the .mkv, could you perhaps provide some insight into how to properly configure PCM, as currently PCM sounds much worse than DD or DTS.

As for number 5 would you mind reading the more detailed question as while you have cleared up the DD/DTS issue I still have the problem of no 5.1. Perhaps this ties into properly configuring PCM?

 

[markw]

I do believe "PCM" is two channels only, as with CD audio, and DD/DTS is passed via "bitstream". Check for this option on your source.

See if there's an "auto" function on your receiver that will allow it to determine the most beneficial method of decoding the incoming digital signal.

 

[Grador]

So regardless of whether my receiver displays PCM, DD or DTS the audio is coming out as PCM?

For the .mkv, could you perhaps provide some insight into how to properly configure PCM, as currently PCM sounds much worse than DD or DTS.

As for number 5 would you mind reading the more detailed question as while you have cleared up the DD/DTS issue I still have the problem of no 5.1. Perhaps this ties into properly configuring PCM?

To specify again, since Mark called it into question. HDMI will gladly do 5.1 PCM.

Skipping around in your questions to #5: It sounds like the only issue you're having is that stereo only games are in stereo only, and that's life. The lights are all lit up on your receiver because your computer is set to output 5.1 and is doing so at all times. When you are playing something in stereo the computer just puts out silence on the unused channels.

For playback of .mkv files, if DD sounds best then use DD when possible. MKV files can (but do not have to) contain DD or DTS audio just like on a DVD but may also contain audio in formats such as mp3 or AAC etc. I think VLC is smart enough to bitstream (send DD/DTS to receiver w/o decoding first) when possible, but decode the audio when it's not.

If that doesn't work out well for you I'll need to know what OS you're using to give you better instructions.


To give you a little more background so that what I'm saying might be a little easier to understand and apply: PCM is a means of digitally conveying uncompressed audio. CD audio is stored in PCM format for instance. The Digital to Analog Converter (DAC) in your receiver is the thing that takes the digital information and turns it into an analog signal to be amplified and sent out to the speakers. The DACs in most receivers doesn't work with DD or DTS, they only accept PCM. This means that internally the receiver will take the DD or DTS compressed audio and "expand" it out to PCM so that the DAC can do it's job.