Surround Sound

Hi,
from what I read, the sound cards on mac pro's are not replaceable.
What is the best, and cheapest way to get surround sound for all things on a Mac pro? I don't just mean music and DVD's but games and others.

Thanks

The same way you would get surround sound on any other system of course. Buy a surround sound system to attach to your mac....

The output is optical. Buy something that supports that and you have Dolby Digital 5.1 support.

Looks like I'll have to spend out more money then. My PC has 5.1 built in. Thanks.

So does your Mac. Optical audio output is by definition digital and supporting 5.1

As the mac will be used for both my business and for pleasure I have been trawling the net trying to find out all the + and - between PC and Mac.

So I do apologise if I'm getting this wrong.
I have read that Mac will only out puts in stereo and you need to buy a Aux audio deck/card to get 5.1. But then it only work with such things as DVD movies and music. Not with games and things like that.