Here are some alternate BGM's for Prontera.
You can download it by clicking on the links below.Piano Version
Rock Version
Taezou Version
Ok heres how to change your Prontera BGM -
but first download 1 from the 3 choices above.
2. extract it
3. Open your RO folder > then BGM Folder
4. Delete the number '08' BGM file from the folder.(You can also move it to another location in your documents if you want to save it for future use.)
5. Copy the version that you have extracted/downloaded.
6. Paste it inside the BGM Folder of your RO
7. And lastly, rename the pasted file '08'.
Enjoy your customized prontera BGM.
NOTE: BE SURE THAT YOU RENAME IT TO '08'if there is some question regarding these steps. feel free to ask.