here's a cfg file opened with notepad. a little different than the three(?) others posted. i suppose it's possible to edit any cfg then rename it and drop it into the rockbox folder and use it right away. here's what i use with most headphones, most lately the hippo vb's even though this was originally done with the tf10s in mind.
# .cfg file created by rockbox 3.5 -
Rockbox - Open Source Jukebox Firmware
bass: -1
treble: 2
channels: custom
stereo_width: 150
show icons: off
crossfeed: on
crossfeed direct gain: -10
crossfeed cross gain: -50
crossfeed hf attenuation: -60
crossfeed hf cutoff: 1000
eq enabled: on
eq precut: 10
eq band 0 cutoff: 20
eq band 1 cutoff: 300
eq band 2 cutoff: 1490
eq band 3 cutoff: 4250
eq band 4 cutoff: 11290
eq band 0 q: 5
eq band 1 q: 22
eq band 3 q: 42
eq band 4 q: 5
eq band 0 gain: 25
eq band 1 gain: -45
eq band 2 gain: 35
eq band 3 gain: 50
eq band 4 gain: 60
dithering enabled: on
timestretch enabled: on
really enjoying the fuze with rockbox. picked up a 16gb micro sd card at a brick and mortar store... so much better than the 8gb limit.