The startup sound in Mac OS X can be rather annoying at times. There are various ways to stop the chime / gong startup sound. The way I prefer to do is with a preference pane called StartupSound.prefPane. This is the set it and forget it method, the kind most people appreciate the most.
How To Disable the MAC OSX Startup Sound
1. Download the StartupSound.prefPane – here – this is a Universal Binary
2. Double-click the downloaded file
3. Double-click the “StartupSoundPrefPane.pkg” icon – this will install the preference pane. Please note you will need to enter your administrator password for this to install
Enjoy the peace… =P