You would have to download a hex editor program to edit binary files. I may have time later today or tomorrow to take a look at the other program I mentioned, which could make things easier than learning how to use a hex editor.
Actually, since you want a specific sound, you could use a sound editor (such as
Audacity) to record it. In DD temporarily set the music, sound effects and voice volumes to zero, then switch to Audacity and start recording 'what you hear', then switch back to DD and walk into a tavern. When you have enough of the ambient crowd noise, you can exit the game, stop the recording, trim the recorded sounds to just what you want and save it. If alt-tabbing out of the game and back causes problems for you, you can start Audacity recording first, then start the game, change volume levels, and load an appropriate save.