Track 14.ogg sounds WORSE after this remake. It is still in mono with a lot of grain. The rest of the tracks however are excellent.
The music that is shipped with the Marathon release is based off of the classic Quicktime synth. This is the fed through fluidsynth which utilized a modern sample set — in this case, Don Allen's Timbres of Heaven. All tracks have been normalized and made working for in-game.
To install, simply replace the Music folder within the Marathon data folder