Lexus GS460 Owner's Manual page 327

"DSP" tab
The sound quality level is adjusted individually
■
The treble, mid and bass levels can be adjusted for the each audio mode separately.
About Automatic Sound Levelizer (ASL)
■
ASL automatically adjusts the volume and tone quality according to the vehicle
speed, wind noise or other noise.
GS_G_U (OM30C11U)
May 21, 2010 1:06 pm
3-3. Using the audio system
Surround on/off
Automatic Sound Levelizer
(ASL) on/off
3
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