Specifications

Getting Started with Mbox30
Peak LEDs
These LEDs are triggered just below analog clip-
ping levels. In other words, if the Peak LEDs
flicker occasionally, the signal is approaching
clipping levels, but they do not necessarily indi-
cate distortion or clipping.
USB LED
The USB LED indicates that the Mbox has re-
ceived power from its USB connection. Once the
USB light is on, audio can pass in or out of the
system.
S/PDIF LED
This LED indicates that channels 1 and 2 are set
to receive digital input rather than analog input.
See “S/PDIF Digital I/O” on page 32.
Mix (Ratio) Control
Mbox gives you the ability to monitor your an-
alog input signals while recording, without the
delay incurred by A/D/A converters and host-
based processing.
This zero-latency analog monitoring is con-
trolled with the Mix knob, which you can use to
blend and adjust the monitor ratio between
Mbox analog inputs and Pro Tools playback.
The Mix knob has no effect when you are using
S/PDIF digital inputs, since it controls the signal
before it reaches the A/D converters.
To listen to just the Source input signal, turn the
Mix knob fully left to Input. To listen to
Pro Tools output only, turn the knob fully right
to Playback.
The output from the Mix control is routed di-
rectly to the TRS line outputs, and is mirrored in
the Headphone ports and S/PDIF output ports.
This ability to blend and control the relative lev-
els of Pro Tools playback and latency-free live
analog inputs can be particularly effective when
overdubbing.
Mono Switch
The Mono switch sums the stereo signal to a
mono signal (delivering that identical signal to
both speakers). This has no effect on Pro Tools
playback monitoring or on the main outputs.
Switching your stereo signal to mono is useful
when you are recording a mono input while lis-
tening to stereo playback, or for checking the
phase relationship of stereo inputs.
Monitoring while Overdubbing
By panning signals to the center, or using the
Mono switch, as opposed to panning them hard
left and right in the Headphone outputs, you
can create a more focused monitor mix to help
minimize distractions while overdubbing.
In situations where you are monitoring stereo
microphones, stereo synthesizers, or any source
pairs with a comfortable balance, you will prob-
ably not want to use the Mono switch.