I have this copied down. Unfortunately, I didn't record where it came from and Google isn't giving up the source. So apologies to to original author.
<QUOTE>
I was after a quick and easy way to make a single coil sound like a humbucker so I used 3 Parametric EQ's in a line with settings from the Boss EQ-20 manual. It fattens up quite nicely.
EQ 1
Low Freq 30hz, Gain 0db
Mid Freq 200hz, Gain 9db
High Freq 1.6Khz, Gain 9db
EQ 2
Low Freq 60hz, Gain 3db
Mid Freq 400hz, Gain 0db
High Freq 3.2Khz, Gain 6db
EQ 3
Low Freq 120hz, Gain 6db
Mid Freq 800hz, Gain 9db
High Freq 6.4Khz, Gain -9db
High Cut 12.8Khz
Level -6db
(All Q settings 0.7)
For the reverse (That is Humbucker to Single Coil) this gets in the ball park:
EQ 1
Low Freq 30hz, Gain 0db
Mid Freq 200hz, Gain -12db
High Freq 1.6Khz, Gain -9db
EQ 2
Low Freq 60hz, Gain 0db
Mid Freq 400hz, Gain -3db
High Freq 3.2Khz, Gain -12db
EQ 3
Low Freq 120hz, Gain -3db
Mid Freq 800hz, Gain -6db
High Freq 6.4Khz, Gain 9db
EQ 4
Low Freq N/A (Set to 0db)
Mid Freq N/A (Set to 0db)
High Freq 12.8Khz, Gain 12db
IOW
A 120Hz -3 dB
B 200Hz -12dB
C 400Hz -3 dB
A 800Hz -6 dB
B 1600Hz -9 dB
C 3200Hz -12 dB
A 6400Hz +9 dB
B 12800Hz +12 dB
</QUOTE>