5870 sound or sound card?

Sc00p007 · 28 Feb 2010 at 14:35

Hi,

I connected my ati 5870 to my onkyo 606 receiver via hdmi. I now have surround sound working in all my games. The onkyo says it is receiving and outputtting multichannel pcm.
Firstly, out of interest, i was wondering what kind of surround sound the pc is decoding for games? When i play a dvd it says dolby digital. When i use my 360 my receiver shows it is receiving dolby digitial too. Is the pc game sound better than this?
I never use headphones, and from now on i will only be using my home theater setup for my sound. Will a dedicated soundcard connected to my receiver give me even better sound quality than the 5870?

My main use for the sound is games.

thanks in advance,

Phil.

Incase you need to know, my motherboard is Asus p6t deluxe with onboard realtek hd audio.

Elfmeister. · 2 Mar 2010 at 05:11

I just bought a Asus Xonar D1 and it's as clear as night and day to how much better it is over the audio from my 5850, which I assume is the same as 5870.

Not sure how you'd link one to your HT with surround sound though, unless you have an optical input.

EddScott · 2 Mar 2010 at 13:36

I thought the ATI cards could output TrueHD to a receiver?

I asked a similar question with regards to movies on a living room PC - graphics card Vs HDMI equipped sound card and was told the HD sound cards were not needed.

Is this not the case then?

Marsman · 2 Mar 2010 at 14:00

Yes, the 5xxx series can.

EddScott · 2 Mar 2010 at 15:09

So if the 5770 was playing back say a Bluray, the receiver would output sound as TrueHD?

Sc00p007 · 3 Mar 2010 at 00:17

From what i have read, the 5xxx series bitstreams dolby truhd and dts ma to a receiver via hdmi (this means i dont need a separate sound card to make the sound better, as the receiver is receiving the exact digital copy of the sound). I am happy with this as i have been using the ps3 to watch my blu rays. Now i will go and buy a blu ray drive for the pc as this machine is quieter than the ps3.
However im still not sure about the quality of the sound in games. I read conflicting posts, some say if using the gfx card with hdmi connected to my receiver, it will be the same as the sound card. Others say it is clear as night and day that the sound card will be better than the gfx card even when being sent to a separate receiver.

Im thinking this is because the decoding isnt done in the receiver, it is done in the graphics card, and the receiver just simply plays an exact copy of what the gfx card decoded? Meaning that the separate sound card does this job far better than the gfx card?

Presuming i am wrong can someone please explain what is actually happening? It seems there is a wealth of information on all other components. When it comes to sound on pc it seems i read a lot of conflicting stories.

Thanks in advance,

Phil.

gurusan · 3 Mar 2010 at 08:47

Elfmeister. said:
I just bought a Asus Xonar D1 and it's as clear as night and day to how much better it is over the audio from my 5850, which I assume is the same as 5870.

most pointless thing ever.

How is it better? In both cases the "sound card" is not doing anything, merely passing a digital signal on to the receiver.

EddScott · 3 Mar 2010 at 10:05

Sc00p007 said:
Phil.

I don't know how much better mobo on board sound is compared to say a Creative XFi card compared to a graphics card. I have a creative card in my PC at the moment and when I thought it was broken I used my mobo sound. I play games through headphones as the PC is in the living room and I couldn't tell the difference.

I think what I will do is firstly try the GPU sound through the HDMI and see how that sounds. Then I'll try the Creative card and see if thats any better (the creative card can only be hooked to my receiver via 3.5 phono to RCA so I'll be amazed if it actually sounds any better.

I'm sure these expensive sound cards do indeed do a better job but the difference really needs to be very obvious to warrant another £180 into a build cost.

gurusan · 3 Mar 2010 at 10:50

EddScott said:
I think what I will do is firstly try the GPU sound through the HDMI and see how that sounds. Then I'll try the Creative card and see if thats any better (the creative card can only be hooked to my receiver via 3.5 phono to RCA so I'll be amazed if it actually sounds any better..

This is flawed as when using your GPU for sound the audio data is sent to the receiver to be converted into an analogue signal.....if you use the 3.5 phono to RCA on the creative you are using the sound card's DAC....

So basically you are testing your receiver DAC + analogue out stage vs the X-FI DAC + analogue out stage AND your receiver analogue out :/

If you guys are using a receiver and feeding it a digital signal then there's no point in getting a sound card at all....you can either feed it the data through your GPU or mobo SPDIF, there's no difference.

Sc00p007 · 3 Mar 2010 at 13:31

Thanks for the replies, it is all slowly getting a little more clear in my head.
Probably through my user error, when i use the onboard sound on the Asus p6t deluxe via optical out, i only getting stereo output for games. When watching a dvd, dolby digital surround sound is output from my receiver. As soon as i connected the gfx card via hdmi, all my games were output in surround.

Thanks for all the replied, very much appreciated

Phil.

Marsman · 3 Mar 2010 at 14:26

The motherboards onboard sound chip must have Dolby Digital Live, or DTS Connect, which encode to 5.1 in real time, when playing games. SPDIF (coaxial & optical) is only stereo. Dolby Digital and DTS were invented to allow multi channel sound to be sent via SPDIF. When watching a DVD, Dolby Digital which is contained on the disc, is then passed on to the AV amp to decode. Majority of PC games do not feature Dolby Digital or DTS, so unless DDL/DTSC is present on the sound device, whether it be motherboard or a sound card, to encode the audio to 5.1, it is only sent as stereo.

HDMI supports multi channel PCM, whereas as SPDIF is only stereo, so no Dolby Digital or DTS encoding is needed.