Is there any way to silence the startup/shutdown sounds without remastering?

I'm guessing I could kill the shutdown sounds ("Shutdown sequence initiated..." or whatever it is) by muting the audio once booted, but this doesn't help on bootup.

I'm experimenting with Knoppix at work and "Startup sequence initiated", while cool-sounding, doesn't quite fit into a corporate environment An option to play a simple chime or other not-so-outlandish startup sound, or simply mute the sound would be nice.

Worst comes to worst I'll clean up my laptop's HD and remaster with a "cleaner" sound tonight.