A funny thing about the "DROID" sound effect is that it was just using the Mac OS built in voice called "Cellos" Put "say -v Cellos droid" into an OS X termina

A funny thing about the "DROID" sound effect is that it was just using the Mac OS built in voice called "Cellos" Put "say -v Cellos droid" into an OS X terminal and you'll hear the exact same thing. (Might need to go to Accessibility > Speech > System Voice > Customize and download the Cellos voice. Doesn't appear to be automatically included anymore.)