The Surround Expansion effect is only available if you are editing a surround audio file (5.1 or 7.1). This offers expanded surround sound settings.    
The following setting options are available:
Slider
Expansion

Indicates the degree of expansion.

Check box
Front Channels

Extends the expansion to include the front channels.

Check box
Side Channels

Extends the expansion to include the side channels.

Check box
Surround Channels

Extends the expansion to include the surround channels.

 


Surround Expansion