That's what the AUTO VOL (Automatic Volume)is for:
With automatic
volume, the 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 LOW, MEDIUM, or HIGH. Each higher setting
will allow for more volume compensation at faster
vehicle speeds. Then as you drive, automatic volume
increases the volume, as necessary, to overcome noise
at any speed. The volume level should always sound
the same to you as you drive. NONE will appear on the
display if the radio cannot determine the vehicle
speed. To turn automatic volume off, press this button
until AVOL OFF appears on the display.
BTW I have them, just havn't installed them yet.
