AC3Filter Audition plugin allows CoolEdit / Adobe Audition to read AC3 and DTS files and write AC3 files.
Download the latest version and unzip it to the Adobe Audition installation folder (for example: C:\Program Files\Adobe\Adobe Audition 2.0)
After this Audition will be able to read AC3 and DTS files.
Just run Audition and open an AC3 or DTS file. It will be represented as a set of mono files for each channel: