This little script is the best! I've had it installed since OS X Lion, and never had any issues. Now I'm on OS X El Capitan and it's still working, never had to re-install! Works through the default audio port, or through little USB speakers like I have set up behind my tower. Makes it sound like the boot chime is coming from inside the computer.
When booting from my ssd the sound doesn't occur until I am fully signed into my account and everything has loaded. I am currently running El Capitan using Clover. I uninstalled it because it sounded way after my computer booted. If you release a new version and want me to try it just let me know.
It's very nice !!! In my hackintosh it works very good !!
I've got an USB Yamaha audio interface the AUDIOGRAM6 .
The only things that i've see that is not like the original mac is that the sound is played after that the logo is charged and the charging line is on the end and this is because all the kexts must to be charged to play sounds. I've see another solution that need to occurred a little electronic circuit -> http://www.tonymacx86.com/powermac-g5/91945-mac-startup-chime-v2-using-arduino.html
It's nice but i hope that somebody implement a solution to inject the audio before the logo using clover, i mean that is possible because clover can just use some hardware maybe implemented a driver like it has in drivers64 folder or drivers64UEFI.