2007 Chevrolet TrailBlazer Owner's Manual - Page 216

AM-FM Stereo with 6-Disc Compact Disc Player with Programmable Equalization and Radio Data System (RDS) (If Equipped) Playing the Radio VOLUME PWR: Press this control to turn the system on and off. To increase volume, turn the control clockwise. Turn it counterclockwise to decrease volume. AUTO VOL: Your system has a feature called automatic volume. With this feature, your audio system adjusts automatically to make up for road and wind noise as you drive. Set the volume at the desired level. Press this button to select MIN, MED, MAX or OFF. Each choice allows for more volume compensation at faster vehicle speeds. Then, as you drive, automatic volume automatically increases the volume, as necessary, to overcome noise at any particular speed. The volume level should always sound the same to you as you drive. If you don't want to use automatic volume, select OFF. If your vehicle has the Bose radio, your audio system monitors the noise inside your vehicle. Then, automatically adjusts the volume so that it always sounds the same to you. To use automatic volume, press the AUTO VOL button until AVOL ON appears on the display. To turn automatic volume off, press the AUTO VOL button until AVOL OFF appears on the display. Standard radio--BoseR not shown 3-44