Quote Exalted Wombat:
Which is why Windows has completely configurable system sounds, including a simple "use none" setting. Surely there's a similar function on Mac?
Those are simply sounds played by the OS (ie. software).
Whereas the Mac startup "bong" comes from the hardware, and you'll get it even on a machine with no OS physically present. Hence any changes are somewhat lower-level operations.
I appreciate this may be a subtle distinction...