Source Audio Soundblox 2 OFD Guitar microModeler - Manual (Page 10)

10 | Controls: Buttons
CONTROLS: BUTTONS
NOISE GATE
This control allows for quick adjustments to the noise gate threshold.
Since distortion effects can have very high signal gain, the background
noise and hum are also gained up and can become undesirably loud.
Enabling the noise gate on the Soundblox 2 OFD microModeler will help
silence the background noise when the guitar is not being played. There
are four noise gate threshold levels: OFF (all LEDs off), LOW, MED, HIGH.
LOW being the lowest threshold and least aggressive gate action, HIGH
being the highest threshold with the most gating action
Note: this button is also used to select and control the function of an
external controller through the MULTI-FUNCTION input. See the External
Control section.
LOW
(EXP)
MED
(MIDI)
HIGH
(HH)
NOISE
GATE
Press button to
select option