reduce bass in mplayer using -af equalizer

http://linux.die.net/man/1/mplayer
-af to use the audio filer, specify equalizer
equalizer=[g1:g2:g3:...:g10]
    0 31.25 Hz
    1 62.50 Hz
    2 125.00 Hz
    3 250.00 Hz
    4 500.00 Hz
    5 1.00 kHz
    6 2.00 kHz
    7 4.00 kHz
    8 8.00 kHz
    9 16.00 kHz
for each band, it can be -12 to 12

the frequency of human speech mainly range from 120 - 250 hertz
so it is,
mplayer -af equalizer=-12:-12:-2:2:0:0:0:0:0:0 -noquiet -nojoystick -nolirc -cache 58 -cache-min 20 -loop 0 mms://mslive05.881903.com/cr1

I do this because the radio stream is bass add-ed, and the human voice is covered by the bass (my local radio)