Stopping the OS X startup chime

At the moment, my Apple G5 is suffering from the OS X 10.3.5 update – it refuses to go to sleep. Which means that I am rebooting once a day, if not more often. The loud system chime on startup had been driving me round the bend – I have been looking for a way to turn if off. In the last day or two I have found several ways to kill the chime:

• on an ad-hoc basis, you can mute the sound output before shutting down – the sound remains muted when you boot next time
• use TinkerTool System (shareware, but you can run it 4 times for evaluation before having to licence it). Licence fee is a reasonable $7.
• you can also use StartupSound.prefPane (freeware), which adds a preference in the system preferences pane to allow the sound level to be controlled.

Because the startup chime is effectively part of the startup self-diagnostics, I feel happiest remembering to mute before I shut down, rather than messing with the software solutions.