I am a bit limited as to what I can do as I don't have a spare PCI slot. I have 2 PCIE 1x slots free and plenty of USB ports.

I've just run some CAT5 round the outside of my house and have a pair of passive baluns that carry HD component and SP-DIF to my plasma and surround sound amp.

While the home cinema kit I've got is fairly top notch I only intend to play the odd game with 5.1 sound and possibly the odd HD movie with 5.1 sound. I discovered this weekend that the SP/DIF socket on my Asus P5N32-SLI mainboard (Realtek 850 on nForce4 chipset) only supports 2CH audio or 5.1 passthrough from a DVD player. (Or it appears to from all the testing I've done this weekend). I haven't tried the toslink socket as I don't have a converter handy.

What can I add which will output 5.1 via the digital sockets rather than just passthrough?

Thanks

Tim

Perhaps you know what you mean, but the question doesn't make sense to me. The job of S/PDIF is to send digital audio data from one place and receive it at another. It doesn't do anything else. The sending device decides what goes into the channel, the receiving device decides what to do with what it gets.

It is a limitation of the audio chip-set. Premium chipsets will send Dolby 5.1 through the SP/DIF port regardless of the source. Cheaper chipsets will only passthrough material that is already encoded in 5.1 (e.g. streaming it from a DVD player). I'm not sure why, but the cheaper shipsets will only present 5.1 from games etc at the analogue ports. I can play Half-Life 2 with the PC connected up to the SP/DIF port on my processor and all I get is 2 channel audio, but I can plug speakers into the analogue outputs and the signals are there.

I hope that makes things slightly clearer.

Tim

TOSLINK is just the optical flavor of SPDIF, the same signal will be present.

What you need is a audio-card that features on-the-fly dolby hardware encoding, to convert your 5.1 analog channels to an AC3 stream

Thanks for the reply. Anything you'd care to suggest? I don't want to spend a fortune and if necessary I can free up a PCI slot.

Tim

I don't have any experience in this area, but somehow I managed to get a 5.1 signal from my PC in pure PCM though SPDIF. I think this was in Vista...

I've got 10 copies of Vista business coming - I'll see what happens when I load it. Microsoft seem to be really slow in shipping it to their partners. What chipset does your Mainboard use?

Tim

I was using it from my X-fi

AFAIK not possible. try to recreate that setup, and then examine yor spdif receivers display/menus for lit AC3 or DTS indicators.

So which cards will create 5.1 on the fly?

Tim

a few are listed here....
http://www.ocforums.com/showthread.php?t=427256

Thanks,

1. You've confirmed what I suspected, and
2. Given me the information I need.

Tim