Questions about digital coax on Sound Cards

[Wingster]

Is there any difference (signal wise) among digital outputs of lets say Sblive 5.1, Audigy 1, Audigy 2, M-audio Revolution 7.1, and other Sound Cards that provides Coax / Optical out? Sound Blaster seems to have all these dsp effects and I am not sure if they are processed on the sound card.

It's just that I am hooking my really old sblive 5.1 (with the coax digital out tray) to a high-end receiver (with all effects off, hopefully i'll get the cleanest signal). Just wondering if it will sound any different with a better sound card. Just not sure if the computer actually decodes the audio from the PC and encodes it back or if it's a straight digital pass thru (Not talking about DVDs, but something like mp3s or wavs) Anybody know?

Also, I am wondering if there's any real time encoding DD5.1 PCI sound cards. I know the Nvidia onboard "soundstorm" does it and makes you go DD5.1 as soon as you turn on your computer. But I can't find any PCI card with the same capabilities and I don't feel like junking my P4 3Ghz for an AMD board -.-

 

[Matthias99]

If you're playing a DD5.1 source, I'm pretty sure all soundcards just pass the data through (as long as your DVD software, etc. supports it). In the consumer level cards, only NVIDIA SoundStorm (which may get released as a PCI add-on card at some point!) can actually *encode* DD5.1, but I believe all of them will output regular stereo on the digital coax/optical out, doing the encoding in software. Haven't tried it, as my old SBLive 4-channel card doesn't have a coax out (time for an upgrade!)

You may well get a higher-quality signal in a better card (an Audigy 2 versus a SBLive5.1, for instance), but how much of a difference it makes on a digital out I can't say. I know that for analog signals the Audigy 2 is a big step up from the SBLive series in terms of SNR.

 

[Wingster]

I don't care for analog or dsp though.. coz the receiver is doing all of that and I wanna know if spending $100 bux on a sound card is worth the difference, IF there is any difference..

 

[VictorLazlo]

I would like to know the same thing. I'm trying to build a HTPC, and I would like to see the purest signal being sent to my Denon receiver.

 

[Matthias99]

In theory, digital is digital is digital.

If you're using the card for decoding a 5.1 signal (plugging it into 6-channel speakers, for instance), the quality of the card matters a great deal.
If all it's doing it passing a digital signal (from something like a DVD audio track) to the digital out (for decoding using an external receiver), it shouldn't matter at all. All the sound card is doing is shoveling some bits around.

SoundStorm will let you take 5.1 audio (such as a game's EAX surround sound) and encode it as DD5.1 for digital out. I presume its encoder is "pretty good" (that being a highly scientific term, of course ), but probably not up to what a professional-level sound card would do.

Anything else at the consumer level is limited to encoding stereo for digital out, but I don't know if there are any noticeable differences between them. Probably about the same difference as between a Live and Audigy 2 for analog: noticeable if you're looking for it and you have really good speakers, but otherwise not much. Most people use these cards for 5/6/7.1 output from games, which means the cards aren't doing any encoding *or* decoding.

I don't know anything about professional level sound cards other than that they exist, and that's what you want to use for very high-quality analog recording and playback. You'd have better luck on a home-theater/audio technlology forum.

 

[f95toli]

About the quality of the digital signal i SHOULD not matter but of course there are people that will tell you different. I can tell you that the general recommendation on hifi/home-cinema forums is to buy an USB device with has an s/pdif connector, the argument beeing that you pick up less noise from the computer. Since these devices are quite cheap I guess you could try.

I would recommend using an optical connection in either case, there have been cases where a voltage spike or a "pop" from the computer have destroyed speakers and receivers, this is caused by ground potential differences and can be avioded by using a toslink-connection instead of a coax.