Hey there,
I do exactly what cchoy said to do. I use the Sound blaster Xfi and I'll give you a quick tutorial on how to mix in 7.1 in vegas.

First setup your project

Whatever hardware you use make sure that the rear channels in the surround panner go to the rear left and rear right speakers in your project (You'll find out what I mean in a minute)

Create 2 bus tracks
Route bus A to the side left speaker and route bus B to the Side right speaker.

Click the padlock button between the 2 sliders on the bus tracks

On bus A bring down the right slider all the way and do the same for bus B on the Left slider

Your ready to begin mixing in 7.1

I'll give you a tip for how I mix when I want something to pan around me.

What i'll do is i'll turn on the automation effects for the main bus and the bus tracks and use a combination of the auto volume and surround panner for panning

Say if I need a sound to pan from the side left across the back of the room and over to the side right speaker I would go in and start with bus A's volume set at 0db (Remeber Bus A is set to output at the side left speaker) and the master bus and bus B's volume at inf dB then I would go over a couple of frames and move bus A's volume slider down to inf db and move the master bus volume slider to 0 db. (Leave bus B alone for the moment but create a leyframe on bus B's volume at this point) Then I would have the surround panners position at the rear left channel and set a key frame, move over a few frames and move the panner over to the rear right channel. Then I would create a keyfram on bus B's volume slider then move over a few more frames turning down the master bus volume to inf db and setting bus B's vloume at 0db.

I Know it's very confusing and I probably most likely didn't explain it well but I HAVE DONE and it works really well.

Now when you render your new 7.1 mix you need to select the microsoft wav file format as your output format.

Then click the "Enable multichannel mapping" checkbox and click channels, a window pops up.

Click the checkbox by surround master. this creates the 5.1 mix

Then click the check box by bus A (Mono Downmix) This creates the 7th Channel

Then click the check box by bus B (Mono Downmix) This creates the 8th Channel

Click ok

Type in a file name and click save. your now creating a 7.1 wave file.

Remember earlier when I said to route the rear channels in the surround panner to the rear left and right speakers? well if you hadn't done the routing like I told you, the side channels and the rear channels would have been swapped with each other in the final wave file. (Anything thats was suppose to come out of the side speakers would of come out of the rear speakers and vice versa) Trust me I've made that mistake before. Anyways your wave file will be pretty big after rendering so I suggest downloading the Windows media encoder from microsofts website (FREE) and converting the wave file to a WMA Pro 7.1 File. If you have a soundblaster card such as the xfi you can use the audio converter included in the software package to convert the wave file as well. (Thats what I use)

If you read this entire thing I appreciate it. I know it's long, excuse any spelling errors. My advice though is t get in there and play around with it, you can't hurt anything!!!!

Chris Smith