Boss GEB-7 Owner's Manual page 6

Equalizer Control knobs
Equalizer Control Knobs
These knobs allow you to boost or cut the
center frequency of 50, 120, 400, 500,
50 120 400 500 800 4.5k 10k Level
800, 4.5 k or 10 kHz within +/-15 dB.
+ 15
Level Control Knob
0
This knob allows you to adjust the output
level of the effect sound to minimize the
level difference between the effect and
- 15
direct sounds.
Level Control Knob
6