The tendency is that if you do not fill all 30 slots of music in the folder, there will be like a 1 to 2 minute delay before the music plays everytime you encounter boss type or normal enemies. Originally his mod has 30 something slots for you to fill the music. I limited the tracks to 6 tracks per combat music category so that IT WILL PLAY EVERYTIME YOU ENCOUNTER ENEMIES. In his mod, I removed all night and day combat music variations as well as locational combat music variations from his simple version mod as well as other tracks in the records using TES5Edit. I feel like Bethesda got really lazy to create regular boss battle themes so they only consider Dragons to have their own combat boss music. I just modified his revolutionary Dynamic Customizable Soundtrack mod to a much simpler one based on his 01 - DCS 1.2 - Simple Version.esp (This is for purist players like me who wanted to still feel the vanilla-Skyrim feel without too much music additions). But dragons aren't the only bosses in this game! Even Alduin, Harkon and Miraak only use generic dragon combat boss music! The dragon priest fights use only normal combat music! Well. With the dragons, yes I applaud them for that. I got really disappointed from the lackluster of combat boss music in Skyrim. I am a huge fan of video-game soundtracks.
