Under the Audio selection drop-down list on the main screen, you can select/deselect which audio streams you want included in the rip. Typically for most blu-rays, the HD audio (e.g. DTS HD Master, or Dolby Digital TrueHD, or both) are the main audio streams and Dolby Digital AC3's are usually descriptive audio, director's comments, etc. Some older blu-rays only have Dolby Digital AC3 only and no HD. Simply deselect the descriptive audio if you do not want that.
The trick is to determine which audio is what. One way is to play the original with either PC software player or standalone player and cycle through each audio track to see what is what. Also be aware that depending on what you are watching (i.e. main movie vs. previews vs. extra features) there may be different options available. HD is mainly usually only used for main movies and some of the production or audio feature clips (e.g., DTS, Atmos) that show before the movie. There may be other ways to determine this but this is usually the method I use if I want more than just main audio.
There are 3rd party tools (demuxers and such) out there that I believe can identify what each audio stream is (i.e. main, vs. commentary, etc.), but I am not aware if DVDFab has that capability or not. (I guess if it did, it would show it). If you are doing a main movie rip and want only main audio, you should always be correct in selecting only the, or one of the HD tracks.
