How to Adjust the Volume for the Alerts on an iPhoneby Lara Webster
The iPhone offers many options for alert tones. Ring tones can consist of one of the device's default tones, or users can elect to use their favorite song to alert them to an incoming call. The iPhone also has several options for tones that alert users to a new text message, while as of 2010 default voice mail and email tones cannot be changed. The volume for all tones must be set to the same level, which users can change quite easily.
Set the Volume With the iPhone Button
Locate the volume button on the upper-left side of your iPhone. This is a long silver button with a dip in the middle that divides the upper and lower portions.
Click the top of the button to raise the volume. To lower the volume, click the bottom half of the button.
Slide the small silver button right above the volume button toward the back of the phone to disable alert tones altogether. When you can see an orange dot, you know that you have slid the silence button into the "On" position.
Set the Volume With the iPhone Software
Go to the "Settings" application on your iPhone's homepage.
Choose "Sounds" from the menu.
Slide the volume bar up and down by placing your finger on the silver circle and moving it to the right and left. The more blue line that is visible, the louder the volume.
Toggle the "New Voicemail," "New Mail" and "Sent Mail" alert tones from on to off by tapping the blue "On" icon for each tone.