I think what you can do with that script is as root issue :
Code:
update-rc.d sound.sh defaults
and make sure its executable :
Oh and the word defaults in the first command tell it, that its able to execute on runlevel 2,3,4,5.
Also since I didn't specify any paths in my examples, these are written in assumption your in the root of the folder where the sound.sh file exists. And do make sure that the file exists in /etc/init.d for doing these examples.