Serious Sam Classics: Revolution

Serious Sam Classics: Revolution

Can I change the music of a level by changing the files in file explorer? or do I have to change them in Serious Editor or something?
I remember following a similar discussion about changing enemy sounds, but when I tried to make changes to the music files in the Music file itself, the game wouldn't play the music. Is there a way to change level music from the files of the game themselves? or can that only be done through the serious editor? Any help is highly appreciated.