Change the volume of your Mac startup sound
Ever wanted to switch off the startup sound on your Mac? StartupSound.prefPane is a simple preference pane that controls the volume of it on your Mac. It mutes the startup sound without changing your main volume setting, so it doesn't affect the rest of your Mac's audio. You can select or deselect the startup volume using the Startup Sound pane added to the System Preferences when you've installed it.
Note, however, that the developer recommends that you backup your Mac before installing StartupSound.prefPane. Therefore, ensure that your TimeMachine backups are up to date before installing it. If this worries you, you can always try using Psst! instead, which isn't quite as good but does pretty much the same thing.
StartupSound.prefPane is probably the most effective startup sound silencer for Macs.
