The DOSBox configuration file is called dosbox-0.74.conf
and is located in
I'm not sure what you're calling "poor quality audio" but you can make sure the "rate" under [mixer] and the "oplrate" under [sblaster] in the dosbox-0.74.conf file aren't set to 22050. If they are set to 22050, you could try 44100 or 48000 instead. Be sure to back up the dosbox-0.74.conf file before changing it. You can use notepad to open the file, but depending on where you installed DOSBox, you may have to run notepad as Administrator to make changes and save them.
If you're talking about something like skipping sound or scratchy sound, that's a different problem.
There's a video showing how to edit the dosbox-0.74.conf file for a different game herehttps://www.youtube.com/watch?v=kCNmuDaBNDY
If you're having choppy sound, check the last post in this GOG threadhttps://www.gog.com/forum/dungeon_keeper_series/how_to_fix_choppy_sound
where "doraz" recommends using DOSBox in Safe Mode.