Lexus CT 200H 2016 Owner's Manual page 258

258
5-2. Using the audio system
Turning the Automatic Sound Levelizer (ASL) on/off
Turning the "TUNE•SEL" knob clockwise turns on the ASL, and turning the
"TUNE•SEL" knob counterclockwise turns off the ASL.
ASL automatically adjusts the volume and tone quality according to the noise level as
you drive your vehicle.
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