Using the sound control buttons on the computer
On the front of your Macintosh are two sets of buttons. The set on the right (marked with the - icon) is for sound control. To use these buttons to increase or decrease the volume of the sounds your Macintosh plays:
nPress the button on the top to make the sound louder.
nPress the button on the bottom to make the sound softer.
_ Sound
control buttons 
Using the Sound control panel
You can also adjust the volume of the sounds your computer plays by using the Sound control panel. To use the Sound control panel:
1.Choose Control Panels from the Apple (K) menu.
2.Open the Sound control panel.
3.Drag the Speaker Volume slider up or down to set the volume level.
Drag the slider to adjust the volume.
After you release the mouse, the sound plays at the new volume.
vBy the way: You can turn off sound completely by clicking the Mute box. When the Mute box is checked and your Macintosh wants to alert you, the menu bar flashes. v
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