More Settings on Your Kindle Fire HD
Sounds & Display
If you tap Sounds & Display in Settings, you see a volume slider that you can use to increase or decrease the volume, as well as a setting for turning Dolby Digital Plus on or off. The Dolby setting improves Kindle Fire HD’s sound quality but may use up more of your battery life.
You also see two settings controlling the sounds for notifications: Mute All Notifications and Notification Sounds. Notifications may come from the arrival of a new e-mail, a completed download, or an app notification (such as an appointment reminder from a calendar app that you may have downloaded).
To modify notification sounds, tap Mute All Notifications to (you guessed it) mute sounds for notifications, or tap the arrow to the right of the Notification Sounds option and, from the list that appears, choose the sound you want to use.