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Sound Card

From OCAU Wiki

Sound, as perceived by humans is an analog waveform but can only be stored or manipulated in digital form on computers so some device needs to exist to output this digital form signal into something that we can hear, which is where the soundcard comes in to convert digital to analog for outputs as well as analog to digital as inputs


Sound Card Manufacturers

Gaming, Sound cards and Surround sound

With sound cards an essential piece of PC gaming equipment it is important to understand how to get the most out of your new surround sound 5.1/7.1 card. Nowadays just about all current sound cards come with a digital plug either optical or coaxial. More info can be found here WIKI DIGITAL CONNECTIONS

First, a little technical info, greatfully provided by rawhide and discussed here OCAU 3D SOUND STICKY

Analogue vs. Digital: Analogue sound travels as waves of electricity that are subject to interference from nearby electronic equipment. Digital overcomes this by encoding the sound into zeros and ones before sending it over the cables, much like the screech of an old modem when you pick up the phone (we don't understand it, but computers can process it). Digital is tolerant to interference, but excessive interference will stop the sound entirely, you either get a perfect signal or none at all.

Digital Formats: When audio is encoded digitally, the equipment at both ends needs to be able to recognise the codes of zeros and ones. That means talking in the same "language", also known as "format" or "standard". There are more, but only three digital formats are in mainstream home sound use. Those being PCM, DTS and Dolby Digital (also known as AC3). For more detailed information on sound formats, try this thread on the OCAU Audio Visual forum.

Encode and Decode: In the context of this thread, these two terms relate to converting sounds to and from a digital signal. Your sound card ENCODEs a digital signal in one of the above formats, while the speaker system (or home theater receiver) at the other end DECODEs that signal. More info on digital sound can be found here WIKI DIGITAL SOUND

Every sound card with a digital plug is able to encode PCM. PCM is uncompressed, it's fast, simple and cheap to encode and used in everything from old digital telephone systems, to Compact Discs . The PCM format supports 2 channels of sound only, that is, stereo. When you play a game on your computer, your sound card is still making a PCM signal and sending that over the digital cable, so you will only ever get LEFT and RIGHT.

To achieve full 5.1 or 7.1 over digital cable your sound card must be able to encode DTS DTS WIKI PAGE and Dolby Digital DDL WIKI PAGE. Most of the new sound cards on the market can do this with the large exception of Creative.

See sound card list: When you play a game on your computer, if your sound card cannot encode DTS/DDL, then your sound card is still making a PCM signal and sending that over the digital cable, so you will only ever get LEFT and RIGHT. If your sound card can encode DST/DDL can you will be be able to have 5.1/7.1 over your digital connection.


Right about now, some of you reading this will be thinking something like "but when I play a DVD on my computer I get my surround sound just fine", and you're correct. In this case the people producing the DVD have already ENCODED either a DTS or Dolby Digital (AC3) signal and stored it on the DVD. Your sound card is simply copying that signal and sending it straight over the digital cable without doing any processing of its own (the same applies to HDTV cards I think, except the AC3 signal is coming, already encoded, from the television broadcast).

Sound Cards List

For ease of definition the cards are broken up into two types:

  • NON DTS/DDL SOUND CARDS: These cards have not been proven to provide 5.1/7.1 surround sound gaming via a digital connection
  • DTS/DDL SOUND CARDS: These cards will provide a 5.1/7.1 surround sound gaming via a digital connection.



Creative Sound Blaster


Onboard Sound Chip

Some users have had success using motherboards will the newest integrated sound chips by Realtek, the ALC888T chip and DTS Connect to achieve a digital connection.

Soundcards and EAX Effects

EAX are a set of instructions to enhance gameplay through sound effects. All soundcard support EAX to some extent. Here is a quick list of what cards support what versions. See the WIKI page for a more detailed description of the differences between the versions.

  • EAX 5: All current model Creative sound cards starting with XtremeGamer up to X-Fi Elite Pro
  • EAX 5: Auzen Prelude 7.1
  • EAX 5: Asus Sound card via driver update. See Below
  • EAX 4: Sound Blaster X-Fi Xtreme Audio
  • EAX 2: Currently all other non creative sound cards

The Future: Asus vs Creative

With the release of their new Xonar Dx, Asus have updated all their drivers to support EAX 5. Now this has upset Creative as the new drivers circumvents Creative's 'pay' for EAR support stance. As such Creative has released the following email:

“Asus is misleading its customers by suggesting that its sound cards now support EAX 5. Asus sound cards do not support EAX 5, nor do they support EAX 3 or EAX 4. The new Asus drivers are falsely reporting EAX 5 capabilities in order to get these games to ouptut 3D audio on Asus sound cards. Furthermore, the several hundred games that support EAX 3 or EAX 4 for delivering in-game effects will not provide those effects from Asus sound cards.“

In respone Eric L. Chen from Asus has made this statement:

“The Xonar series driver update for DS3D GX 1.0 to DS3D GX 2.0 is our response to feedback/criticism favoring compatibility with games that feature EAX 5.0. DS3D GX 2.0 allows gamers to enable EAX sound options/schemes in games on Vista and legacy Windows XP. The solution involves:

- Enabling EAX5.0 sound setting in games - Redirecting DirectSound3D Hardware and EAX calls to the DS3D GX core - Upgrading the DS3D GX engine.

The updated engine: - Revives multi-channel (128 voice) 3D positional sounds and enhanced environmental reverberation effects on Vista for most DirectSound 3D HW compatible games including EAX 2.0/5.0 game titles. - Installs automatically with driver updates. DS3D GX aims to be more convenient and intuitive than Creative’s ALchemy solution, which requires users to manually setup and assign games into the support list. Moreover, Asus does not charge its users for driver upgrades. - Retains vivid 3D sound and EAX effects for Vista users in most existing titles that do not support OpenAL. - Allows users to reproduce comparable 3D positional sounds and EAX effects to native EAX 5.0 sound devices in EAX 5.0 game titles, instead of reverting to stereo, 2D, or Windows-emulated 3D sounds. - Features VocalFX voice processing technology, which can apply realistic reverberations to users’ voices relevant to the dynamic in-game landscapes (VoiceEX), emulates background scenes as you use online chat (ChatEX), and modifies vocal pitches to disguise a user’s identity (Magic Voice).

Our implementation is not a 1:1 reproduction of EAX 5.0. Rather, DS3D GX allows users the choice to universally access gaming audio effects that would otherwise be locked behind specific X-Fi cards and ALchemy-patched game titles. While we do respect the capability of a dedicated DSP processor to offload the CPU work, we believe performance differences will continue to diminish based on the power of today's popular CPUs. We also expect more game developers to adopt software DSP effects for their flexibility and universally guaranteed user experiences. That being said, Asus will continue responding to customer requests with products that unite the best in consumer audio with the most innovative features.”

So the Sound Card wars begins.

For more info there is a good discussion in the PC Audio forum on this topic.


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