Equalizer

[jaaptina]

width_type=o means octave. You should specify the width in a few octaves. The whole bandwith is probably about 10 octaves. So 500 is way to much .
I advise to start experimenting at
convOut=-af equalizer=f=20000:width_type=o:width=2:g=-5
for one octave down and one octave up from 20000hz.
One octave down from 20000hz is about 10000hz.
One octave up is about 40000hz.
So you will reduce frequenties from 10000 to 40000 with width_type=o:width=2.