I believe a sound card which was designed or is capable to send out digital signal, will have, at least, an add-on board or connector to do this.
If the sound card is able to transmit a digital audio signal, even if the sound card does not have the ability to decode any dolby surround format, and if it can do this without altering or degrading the audio signal, the capable decoder-receiver at the receiving end will handle the rest.
The type of decoders available in a particular unit will be explicitly mentioned in the manual and usually printed or labelled or embossed on the receiver's casing. Only those decoders which support PLII Decoding can decode the PLII and so on.
Some units, like the SR5002, can decode multiple formats - Dolby DTS, Dolby Digital, 5.1, 7.1, SRS, Virtal Surround, etc.
A digital bitstream, which is transmitted via the co-axial or the optical cable, will be decoded automatically to the respective format when the receiver is set to "AUTO". When playing a DVD, depending on the type of sound selected in the audio menu on the dvd, the said format will be played. I use Intervideo WinDVD 8 which transmit the audio digitally via the X-Fi to the receiver. X-Fi itself is able to decode 7.1 channels but I usually bypass the X-Fi, so that the digital audio gets decoded only at the receiver.
As you can see from the picture, there is a separate 7.1 channel section at the top left of the back panel. I connect the X-Fi's audio out using the back of the card to send signals directly to the respective 7.1 channels directly. For modern gaming, I use this mode (7.1 CH).
I use the X-Fi's I/O drive to send the digital audio to the receiver while watching movies. Again, depending on the type of Audio selected at the DVD Audio menu, you get the same quality here too - DTS or Digital or a simple 5.1.
The I/O Drive is also used for transmitting MIDI data to the MT-32 from within dosbox for playing dos games, even in Windows 7, as in my previous post.
My PS3 is connected to the receiver via optical and gives a DTS gaming experience. The PS2 gives Pro Logic II Experience (also via Optical) and even my PSOne, which is connected via the ordinary 2 channel audio cable can be upmixed to play the Dolby Surround sound like in Need for Speed III. Even the PSOne's FIFA games will give out true stadium experience - the crowd sounds over the surround speakers.
Generally, a good receiver's UPMIXING capability is jaw dropping. By this, I mean if you want to experience true Surround with Dos games, it's possible with just an ordinary audio out stereo L/R cable.
Any good sound card, including the MX300 will perform well.
Upmixing, takes the normal stereo analog source and "upmix" it to a surround format - most commonly the newer Dolby ProLogic II Ex format. I believe any good card will do with a good receiver.
If the game, even an old dos game, supports Dolby Surround (Wing Commander IV comes to mind), the result is just that - Dolby Surround, even if the signal is NOT sent over a digital line. I'm not sure if an anolog signal can be decoded but the result is truly amazing.
(I wonder if this is the way companies like Origin had in mind when they released the Dolby Surround format in the Wing Commander IV for Dos game - remember the Train Dolby runner? - I can't think of any other way for a dos game to transmit digital sound via a digital capable cable - coaxial or optical).
The problem comes when playing a 4 channel and 2 channel POSITIONING gaming - more so with 2 channel gaming with upmixing.
Upmixing will spoil the expereince if listening to sound effects which simulate the hind semi circle range i.e. from +90° to +270° range.
The problem with 4 channel gaming without a discrete 4 speaker system, or at least in my case, is that, there's no option to choose a 4 channel upmixing. If I disable upmixing, it goes to stereo - only 2 channels. If upmixing is enabled, it goes to ProLogic II (5.1) or Pro Logic II Ex (7.1) mode (selectable). My speakers are connected in a 7.1 configuration. For 5.1 upmixing, the side left and side right speakers will be ignored. So the front right or front left will have small mix-up with the centre channel in 5.1 mode. The 7.1 mode will have a small mix-up at the side lfet/right level when playing the rear right/left sounds.
These games - especially with Aureal3D Vortex 1 is best heard with an ordinary 2 speaker setup - because it was developed with 2 speaker setup in mind, at least, the Vortex 1. I believe till date, Aureal3D is the best 3D audio positioning system with ordinary 2 speaker set.
Kreshna Aryaguna Nurzaman wrote:I think you can disable upmixing to get a correct sense of positioning, although you'll only hear it from two speakers (front left and front right).
Yes, you're right. 😀
Edit : If a sound card allows digital sound to pass through it, it can send any format - Dolby ProLogic/ProLogicII/DTS/Digital/etc. The card does not need to worry about what format it is transmitting, as long as it is transmitting a "digital" audio signal, in which one Dolby type or another is encoded within it.