Debbie, this is a follow up to Grazie’s excellent (as usual!!) posts.
First of all, here’s a link to Mark’s Bitrate Calculator that Grazie recommended.
I make three changes to the default settings.
Both are accessed by clicking on the Settings button in the lower left corner of the main screen.
The first one is to click the 1 Kilobit = 1000 bits button.
Next, set the Audio encoding type and Bitrate dropdown menu to 192 Kb/s – Dolby 1.0. This is the default setting in Vegas and will work fine for your DVD creations.
Finally, change the Safety Margin to 5% from the default 1%.

Here’s a screenshot with your settings.

Now on to your encoding settings.
You never said if you were using Vegas Pro or Vegas Movie Studio. The following screenshots are from Vegas Pro so I hope they work for you.
Click Render As in Vegas, set the settings as shown and then click the Custom button.
On this tab, slide the Video Quality slider to its highest setting.
Click the Variable bit rate and Two-pass buttons.
Enter the values from the bitrate calculator.
You’ll notice that I set the Max value to 8,000,000 instead of the recommended 9,608,000 (FYI, the last 3 zeros are assumed by the bitrate calculator). My personal feeling is that the Max value should never exceed 8,000,000 as the quality of some blank DVDs and players leave a lot to be desired and settings that are too high can cause playback problems. Other users may disagree with me but I’ve burned thousands of DVDs using this method and its never let me down.
You can save this setting by going to the Template box at the top of the screen, entering in whatever name you want and clicking the floppy disc icon to the right to save it. I have several presets saved and use them all the time.
Finally, click on the Project tab and change Video rendering quality to Best. This will result in slightly longer renders but the final quality is worth it.



Let me add a few more comments here.
If a project is 70 min. or less, I use a custom CBR setting of 8,000,000. Anything longer and I always do a custom 2-pass VBR render with settings determined by the bitrate calculator.
Render both files to the same folder and give them the same name. That way, when you load your video file into DVD Architect, the audio file will automatically follow.
Good luck with the project and please let us know of you have any more questions.