I know this thread is old, but its easy.
Just make sure, you add your coordinates from your instance or dungeon in Data -> regioninfo.txt
And make sure, you add your coordinates in Media _> server_dep -> silkroad -> textdata -> regioninfo.txt
Like this :
#TOWN SURVIVAL
235 98 ALL
235 99 ALL
235 100 ALL
236 98 ALL
236 99 ALL
236 100 ALL
237 98 ALL
237 99 ALL
237 100 ALL
Now your Game will know the location -> SURVIVAL
Now go on effectenvsnd.txt and add this at the buttom
<1> SURVIVAL
"YourMusicFile.ogg"
<2> ³·
<3> "dd_mainwind.wav" 0~0
<2> ¹ã
<3> "dd_mainwind.wav" 0~0
Now you have music
have fun all <3