The ASND - Adobe Sound Document file is the file that is automatically created using the Adobe SoundBooth program. The program is used for sound editing on the computer in digital file formats and it is commonly used by musicians or sound engineers, to edit and save the finished sound file for use in applications and productions. The Adobe software update is called Adobe Audition CS6, which replaces the earlier SouthBooth program. However, some audio producers still use the older format of software and it is still considered one of the best.
If you have difficulty with the files in producing sound edits using SouthBooth, you can refer to their tech support section on the Adobe website. As long as you are organized in creating your sound files, you shouldn't have much of an issue. The file type, .ASND is most used for editing and applying sound effects before exporting the finished audio files into a video file for further editing.
Sound is a very important aspect to video editing, as well as audio editing. the .ASND files allow you to save variations of the same file via the edit settings and apply them all in the same document or file. These are called "nondestructive" changes, which means it keeps the original file as it is, while allowing you to create new effects and results. This allows you to try out the new combination to see if you like it, while saving the original file in case you change your mind.
So if you are editing in Adobe SoundBooth and you want to make changes, simply go back to the original ASND - Adobe Sound Document .ASND file and bring it back in and you can edit in a different way to compare results. Then pick the one you like best that suits your audio production task. The finished audio can then be brought into a video for further effects processing, or into other applications.
Versatility in media production is very important because often many "takes" are involved until the desired result is reached. Adobe's SoundBooth program allows this versatility through linear, nondestructive editing, which yields a predictable final result.