User guide

Mbox Pro User Guide6
Input Combo Jacks (Mic/DI)
These combination jacks (Mic/DI) provide XLR
and 1/4-inch (TS) inputs for Input channels 1
and 2.
Gain/–20 dB Pad Switches
These knobs adjust the input gain levels of
Mic/DI 1 and 2, or Mic 3 and 4. Turn the knob
clockwise to increase gain, and counter-clock-
wise to decrease gain.
If your input signal is too hot even with the
Gain knob at a low setting, pull the Gain knob
out to engage a “pad” that attenuates the signal
by –20dB.
Front/Rear Input Source Switches
These buttons select the input source for input
channels 1 and 2. When “out”, the front panel
Mic/DI input is active; when “in” the back panel
Line Input is active for that channel.
Soft Limit Switch
These switches engage a soft limiter on that
channel, applying a smooth, overdriven tape-
type limiter to strong input signals.
Mic/Line Input Source Button
These buttons select the input source for input
channels 3 and 4. When “out”, the back panel
Mic input is active; when “in” the back panel
Line Input is active for that channel.
LED Ladders (Inputs 1–4)
These four, eight-segment LED ladder-style me-
ters illuminate green in the presence of audio
signal, and illuminate red when the signal is
about to clip (overload) the input. The LEDs are
associated with signals routed from inputs 1–4.
48V Switch and LED (Phantom
Power)
The 48V switch toggles phantom power on/off
for all mic input channels. The LED, when lit,
indicates that 48V phantom power is active on
the XLR Mic inputs.
About Phantom Power
Most condenser microphones (such as an
M-Audio Solaris) require phantom power to op-
erate. Dynamic microphones (such as a Shure
SM57) do not require phantom power to oper-
ate, but are not harmed by it.
If you are not sure about the phantom power re-
quirements for your microphone, consult your
microphone’s documentation or contact the
manufacturer.
Although phantom power can be used
safely with most microphones, it is possible
to damage some ribbon microphones with
it. Always turn off phantom power and wait
at least ten seconds before connecting or dis-
connecting a ribbon microphone.
When using phantom power, Mbox Pro’s
maximum current per microphone is 10 mA.