User Manual

Appendix A: Using the Driver Control Panel 47
Disable Host Control
This setting lets you rest control of the Driver
Control Panel from Pro Tools. When you launch
Pro Tools, it takes control of the Driver Control
Panel's first stereo mixer. If you want to obtain
full manual control of the Driver Control Panel,
choose this option.
Clock Source
This setting determines the clock source to
which Mbox is synchronized.
Internal If you are using Mbox by itself (i.e., with-
out other digital devices or an external clock),
select the Internal option for the interface to
work properly.
S/PDIF If have connected a S/PDIF device to
your Mbox and would like to use that device as
the master clock source, select the S/PDIF op-
tion. This will make Mbox clock to the external
device’s clock.
Sample Rate
This drop-down menu sets the sample rate of
Mbox. Note that when using the interface with
an ASIO or CoreAudio application, the sample
rate can also be determined by your audio appli-
cation. This parameter may not be editable from
within the Mbox Control Panel if your audio ap-
plication is running. In this case, any changes to
the sample rate must be made through the audio
application itself. If the application does not
provide a way to set the sample rate, quit the ap-
plication, then change the sample rate through
the Mbox Control Panel.
When the sample rate is locked to an external
digital clock source, the Mbox’s LED is solid
blue. When the sample rate is set and there is no
digital clock source detected (or cannot lock to it
for some reason), the LED will blink. (A message
appears at the bottom of the Hardware Settings
section stating that: “External clock not de-
tected, Audio Streaming is Disabled.”).
Buffer Size (Windows only)
This menu sets the size of the input and output
buffers on Mbox.
Buffers are used to help keep audio hardware
and software running smoothly by processing
audio in groups of samples rather than one sam-
ple at a time. Due to variations between com-
puter hardware and software, it is impossible to
recommend a single optimum setting for all sys-
tems. It may be necessary to experiment with
various settings until you find the best buffer
size for your system.
The goal of setting a buffer size is to reduce it as
much as possible without hearing any clicks,
pops, or other glitches. If the buffer size is too
small, the computer will not be able to make all
the required audio calculations on time and you
will hear pops, clicks, and stuttering in your au-
dio streams. On the other hand, if the buffer size
If you want to use the Low Latency Monitor-
ing option of Pro Tools, this option must not
be checked.
In Windows Vista, when using the Mbox
WDM/MME (i.e., non-ASIO) drivers, the
sample rate of the interface (and your audio
software) is always determined by this
drop-down menu. Your selection in this
menu is the only item that will appear in
your audio application. For example, if you
select “44.1kHz” in this menu, your audio
application’s control panel will only display
“44.1kHz” and you will not be able to se-
lect any other rates from within the applica-
tion.