^ DXA Addons only work with Rebirth.
no config needed, just place the DXA file into your Descent or Descent 2 folders.
if you just want to listen to the files...
rename the .DXA to .ZIP and unpack.
I only play with Rebirth, actually. And for some reason, Total Commander allows me to enter the DXA package and extract the files from there without a problem. It must recognize that it's a ZIP-style package, even though the extension is different.
As for the files, the ones I got are actually AWE64, and the difference between those and the midis rendered by my system is so negligible that they actually probably worked fine, only I couldn't hear any difference