PC Gaming & Lossless 5.1

Hello!

I have some questions about gaming & lossless 5.1 surround.

How I'm planning to set it up;

- hdmi cable from 670 GTX to receiver which is ofc also connected to speakers.

What I want;

Lossless surround sound from blu-ray movies & most importantly gaming.

Where of course codecs such as Dolby TrueHD and Dht-hd master matters.

1. Do I need Dolby Digital or DTS for 5.1 gaming (Or Dolby Digital Live for that matter) if I use a HDMI from GPU to receiver and send the signal as bitstream, or "raw" PCM? Letting the receiver convert it to analog?

2. The reason I'm asking the above is because I'm always reading about analog and 5.1 surround. Analog cables aren't really -NEEDED- for 5.1 lossless surround sound in gaming, is it?

3. Do I need a sound card?

Thanks!

- lillemakken

No you don't need, or want, Dolby Digital Live or DTS Interactive if lossless 5.1 is your goal. You need an HDMI output, your graphics card will do or you can get an HDMI soundcard, and you need a receiver that can do LPCM over HDMI which most modern ones can. That's all.

I do it (7.1 in my case) and the process is my Auzentech HTHD card is hooked via HDMI to my receiver and that's all. No other connections from the computer. If I wanted, I could use my video card instead, but I like some of the things an X-Fi chip can do and the HTHD is an X-Fi with HDMI out.

In terms of Blu-rays movies, if you want bitstream to the receiver, you have to tell your blu-ray player to do that. Some will do it, some won't. PowerDVD does, at least if you have the more expensive versions of it.

Analogue cables are not only unnecessary, they are undesirable. All they are is a place for a ground loop to show up. All your audio will go down the HDMI cable, there's no need for anything else.

Sycraft nailed it all on the head. If you're passing video through your receiver to your monitor via hdmi, it should be pretty straight forward.

However, if your display can't be powered by hdmi (higher resolution or refresh rate than 1080p@60hz), you can configure your receiver as a secondary display to allow hdmi audio to be sent to it, even though no display will be attached to your receiver. You can't disable the secondary display without also disabling the hdmi audio, so you may occasionally run into situations where a window is opened on your virtual display you can't see. So this isn't ideal, but can be done.

Finally, if you are planning on using surroundview AND sli AND hdmi audio, you may run into some issues. I have reported these to nvidia direcly, but they have been ignored

CrazyRob said:

... You can't disable the secondary display without also disabling the hdmi audio, so you may occasionally run into situations where a window is opened on your virtual display you can't see...

Click to expand...

Which is why you set the receiver as a clone display so you don't run into those issues.

Thanks for very informative answers, guys!

One more question!

What if I'm getting an internal blu-ray player? How does that work with what you said Sycraft, about telling the blu-ray player to do that in this case?

Oh, and one more!

My display is already going from a DVI slot through a DVI cable directly to my screen. The HDMI output is right next to it, un-used.
I don't need to pass my display also through the receiver then? Can't I just let that stay as it is? I don't need to touch that right, while letting the 5.1 lossless audio go through the HDMI-port and into the receiver? Or are there some major benefits of letting the display also go into the receiver?

Also... Will there be some lag on the sound having it going from HDMI - Receiver then converted and out into the speakers? I mean, if I'm playing a game, I can imagine that will be quite annoying. And if there will be, any solutions for that?

Thanks again!

- lillemakken

Probably worth mentioning, it seems like most newer Blu-Rays use one of the HD codecs for lossless instead of having PCM 5.1 as an option. In those instances, you'll want to tell PowerDVD to have your receiver decode the signal (assuming your receiver supports Dolby or DTS HD). It's not really that big of a deal and a lot of people swear you can't really tell much difference between DTS-HD and simply having PowerDVD convert it for you, but if you're a perfectionist - it's what you'll want to do.

For games, all you have to do is just send the HDMI cable from your video card to a receiver and make sure you use the Windows sound panel to set everything up for 5.1 speakers. The games themselves will handle the rest.

Hehehe, you may be able to pass gaming audio in a lossless format to your receiver, but the source is certainly not lossless.

xp3nd4bl3 said:

Hehehe, you may be able to pass gaming audio in a lossless format to your receiver, but the source is certainly not lossless.

Click to expand...

That is not entirely correct. http://www.evga.com/forumsarchive/tm.asp?m=100745402

Quoting "sirmasterboy";

" The audio that is in video games is made up of lossless stereo wav samples at 1411kbit bitrate. All of these sounds can play at once when things happen in the game and overlap. All of these sound clips are then layered, flatened, and sent out your sound card as 1411kbit per stereo channel.

Now, 5.1 sound is made up of 6 channels. Green-(left,right) Black-(rear-left,rear-right) Orange-(Center,LFE(Sub)). In full lossless quality, this takes 3 stereo signals to transmit. This leads to 1411kbit x 3 or a 4233kbit bitrate. "

Click to expand...

There are definitely games that utilize pretty high fidelity audio. You'd be shocked how many of those random containers formats contain a boatload of giant WAV files.

Ryom said:

Which is why you set the receiver as a clone display so you don't run into those issues.

Click to expand...

But doesn't the clone display go with the lowest resolution?

I remember trying this when I decided to get bitstream from my computer. I currently use a Dell U2711 monitor and a receiver for sound but if I remember my U2711 was displaying 1080 resolution when I went clone.

So right now I get the secondary monitor problem. I just ignore but occasionally some of my icons go there, and some of the game windows or my mouse...

you could also get a receiver with a passthrough option. where is takes the audio and passes the video signal unaltered. of course you wont get an OSD through your display but not important.

Btw, do I need a receiver with video upscaling, or SHOULD I? If I place a HDMI cable between the receiver and monitor too? Or isn't that necessary at all?

Also, will I get a sound delay if I do NOT link the receiver up to the monitor too?

Some receivers don't process audio unless there is an active HDMI endpoint attached to the output. Even if you clone the display, such a receiver won't process the audio without a monitor or TV connected to it. Even if you connect a monitor or TV to it, some monitors and TVs don't actively receive HDMI signals unless they're powered on or switched to that input.

I have such a receiver, but fortunately my U2711 keeps the HDMI input active even while switched off (while I'm playing on my 3D Vision 2 monitor) or if I'm using the the U2711 on the DVI-D input for 2560x1440.

The issue isnt lossless for movies, its whether your kit supports high definition audio, whether your kit can expose the difference and whether you care about it enough.
Any one of the DAC, cabling, connectors, pre-amp, amplifier, speakers, configuration and your ears/brain can reduce the perceived quality of high def audio.

Lossless CD 16/44K isnt as good as lossless 24/192K if you have good enough kit and can appreciate the difference.
Both are classed as lossless, even though neither is actually lossless.

If you want high definition surround audio, you need to use HDMI to your AV amp, or analogue with a good DAC feeding to your amps analogue inputs.
SPDIF supports high def stereo but not high def surround. To get 5.1 down SPDIF it has to be compressed.


When I was using a good quality Onkyo AV amp (as the surround DAC and amp via HDMI), I couldnt tell much difference between CD and high def audio quality.
I tried it with a decent analogue soundcard using the Onkyo as an amplifier stage only and it was a little better, but still not impressive.
With an Oppo 105 Blu ray player (as a PC soundcard) and dedicated power amps, the difference is very noticeable, lovely.
(using ribbon tweeter speakers)

Lots of mentions for HDMI but a trusty old optical cable will also suffice if you have the hardware to support it.

Optical is SPDIF, see my post above yours.
It is lossy when used for 5.1 even at CD quality, what the op said he specifically doesnt want.

Nenu said:

Optical is SPDIF, see my post above yours.
It is lossy when used for 5.1 even at CD quality, what the op said he specifically doesnt want.

Click to expand...

Hmm, learn something new every day. Cheers for the clarification.

mr_zen256 said:

Hmm, learn something new every day. Cheers for the clarification.

Click to expand...

It gets confusing since audio standards often aren't very standard. S/PDIF is a real old standard and was designed for just two channels. So be it coax, optical, BNC, or XLR, it is lossless for two channel audio, at any sample rate you like, that isn't specified and higher sample rates just use higher clocks (though as a practical matter wires can only handle signal rates up to a certain point).

However S/PDIF has no provision for surround sound. It was spec'd back when there wasn't such a thing outside of special setups. The fundamental spec has never been expanded for it. So, how then do you do it? Using compressed surround codecs, specifically Dolby Digital or DTS. What you do is take the compressed data stream and just embed it in an audio signal. If you listen to it directly it is static (in the case of DTS) or alternating periods of static and silence (in the case of DD). You then need a device (like a receiver) that understands that compressed signal and can decode it.

It all works real well for movies. Dolby Digital is actually pretty low bitrate (only 320kbits in the original theatre spec) and DTS streamed off of compressed CDs that were sync'd to the projector via timecode.

Something that then make it a bit more confusing is the fact that optical cables are used for things other than S/PDIF. Toshiba made the TOSLink connectors that are used with optical S/PDIF. However Alesis decided they'd like to have some of that and used them for their ADAT Lightpipe spec with ADAT recorders. That spec carries 8 channels of 48kHz.24-bit uncompressed audio down one cable. Thing is, despite using the same cable, the signaling is not at all the same and nothing in the consumer space uses the Alesis uncompressed spec.

There never was a widespread consumer uncompressed multi-channel digital audio connector. Some companies like Denon had a proprietary one, but nothing standard. HDMI fixes the problem, for the most part. It can handle 8 channels of uncompressed audio, transmitted during the video blanking period (there is no provision for audio without video). It also can do compressed audio directly, which is often used for movies.

lillemakken said:

Hello!

I have some questions about gaming & lossless 5.1 surround.

How I'm planning to set it up;

- hdmi cable from 670 GTX to receiver which is ofc also connected to speakers.

What I want;

Lossless surround sound from blu-ray movies & most importantly gaming.

Where of course codecs such as Dolby TrueHD and Dht-hd master matters.

1. Do I need Dolby Digital or DTS for 5.1 gaming (Or Dolby Digital Live for that matter) if I use a HDMI from GPU to receiver and send the signal as bitstream, or "raw" PCM? Letting the receiver convert it to analog?

2. The reason I'm asking the above is because I'm always reading about analog and 5.1 surround. Analog cables aren't really -NEEDED- for 5.1 lossless surround sound in gaming, is it?

3. Do I need a sound card?

Thanks!

- lillemakken

Click to expand...

1. A GTX 670 can bitstream everything you need. As long as your receiver supports it will bitstream it.

2. For PC games the sound will be LPCM to your receiver. Which means the audio going into your receiver is decoded by the device (PC) and not the receiver.

3. No you do not need a sound card. Unless you want any type of extra processing to the audio. You're unlikely going to tell the difference in audio fidelity.

So are you guys saying that if you go hdmi from your video card to a home theater you will get 5.1 surround in games? I bought an Auzentech Bravura hooked up via optical to my amp since I thought you needed DD Live to get true 5.1 surround in games.

guitarguy6 said:

So are you guys saying that if you go hdmi from your video card to a home theater you will get 5.1 surround in games? I bought an Auzentech Bravura hooked up via optical to my amp since I thought you needed DD Live to get true 5.1 surround in games.

Click to expand...

Yes. You will need to enable the hdmi as a second monitor to make the connection active though which is annoying. Your pc will aways handle the sound processing and output through pcm in games. On video files depending on software you can just let your pc handle the surround sound or bitstream it and let the receiver handle the decoding directly (like dts or whatever).