Like Video, the Audio quality and size also depends on the profile that you use to make your movie in Windows Media Format. The quality of Audio is determined by its frequency. The profile selected at Medium setting saves audio at 8 KHz. This is appropriate when your requirement is streaming your video across the internet with a 28.8 to 100 Kbps connection. However, if you need your video for playback on your computer then you will have to use a better profile. Good quality audio is produced when they are sampled at 16 KHz or higher frequencies.
Select "Others" from the Settings box when you configure Windows Media Format Properties in the Make Movie Wizard to list all the profiles available to you. Now you can select a Profile that matches your requirements in Video Dimension, Frame Rate and Frequency.
To know more about the selected profile you may click Properties. To know the dimension, frame rate and frequency of your original file you can refer to the File List in the Collections window. These video/audio properties are displayed in the File List along side your original file. Once you know the original properties you can easily select an appropriate profile.
Video Edit Magic also provides you with an option to Auto Select a profile. Just select Windows Media Format from the output section in the Make Movie dialog and click Auto Select when configuring Windows Media Format Properties. If an appropriate profile is found, it will be automatically selected for you.