Even though the startup sound for Ubuntu is short and pleasant, it can become annoying. I got tired of hearing it each time I logged into my system so it had to go. Here’s how to quiet it down:
1. Click System, mouseover Preference, and select Sound.
2. When the Sound Preferences window appears, select the Sounds tab.
3. Go to the bottom and click the Log in dropdown.
4. Scroll down and select No sound.
5. Click the Close button.