Ok first you open this folder C:\Programme\"ServerName"\music you will see 15 music files, but we need only 7 files.
City Music
1000-1 Cronus
1000-2
1000-3
1000-4
2000-1 Elven City
2010-1 Misty Marsh
3000-1 Gobi Desert
3000-2
4000-1 Ice Land
5000-1 Island
6000-1
7000-1 Dark Marsh
7000-2
7000-3
7000-4
And now we will change the Cronus music file name ---> 1000-1.
Now you put any some music that you want my music is darius & finlay do it all night.
Now you have a copy of your song then you will delete the music city in the moment we want to change Cronus music delete now the file 1000-1.
Now you rename your music too 1000-1
Explain
1.You delete the music file.
2.You put the music that you want to hear.
3.Rename the music copy too the file name Check the list all of city music.
4.Save it and start your client and hear the music.