MOTU 1248 User Manual page 75

MOTU interface to route the input directly to your
outputs. For details, see "Mixing tab" on page 22.
The mixer in your MOTU interface even provides
zero latency effects processing (EQ, compression
and reverb), which can be applied to the signal.
Direct hardware playthrough / Direct ASIO
monitoring
When managing your live monitor mix through
your MOTU interface mixer, remember to disable
your DAW's live monitoring features, so that you
won't hear record-enabled tracks in your DAW.
Also note that your MOTU AVB interface does not
support Direct Hardware Playthrough in Digital
Performer, or the Direct ASIO Monitoring feature
(or similar) offered and other DAWs, which lets
you control no-latency hardware monitoring from
within the host application. Instead, you can use
the MOTU Pro Audio Control web app mixer
("Mixing tab" on page 22) to make these live
monitoring connections manually.
If you don't require any effects processing on the
input signal (no reverb or compression, for
example), all this takes is one click in the routing
grid to route the input being recorded to the output
you are using for monitoring.
If you are recording a mono input that you'd like to
monitor in stereo, or if you need to apply effects to
the monitored signal, you can simply route the
input to the mixer in your MOTU interface. This is
done by opening the Mix In group in the Outputs
column along the left side of the grid (Figure 7-7
on page 79), and clicking the tile at the intersection
of the input's column and the desired mixer input's
row. Once routed to the mixer, use the input
channel, reverb bus, and monitor bus in the mixer
to apply effects as desired, and perhaps include
other channels to the mix, and then assign the
monitor bus output in the routing grid to the
output you are using for monitoring.
W O R K I N G W I T H H O S T A U D I O S O F T W A R E
In either case (routing directly in the grid or
routing through the mixer), be sure to maintain the
input's connection to the computer as well, so the
input signal can be recorded in your host software.
In other words, you'll want to make sure there are
two tiles enabled in the input's column in the grid:
one tile for the connection to the computer and
another tile for your monitoring output (or a mixer
input, if you are using the mixer to apply effects). If
you need to route the input signal to other
destinations, too, you can certainly do so (you can
route the input to multiple destinations).
Monitoring through your host audio software
If you do need to process a live input with host
software plug-ins, or if you are playing virtual
instruments live through your MOTU audio
hardware, you can significantly reduce latency by
adjusting the audio buffer setting in your host
audio software, as explained in the next section.
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It is important to note that monitoring delay
has no effect on the recording, or playback, of
audio data from disk. The actual recording and
playback is extremely precise, it is only the
monitoring of your live input signal which may be
delayed.
Adjusting your host software audio buffer
Buffers are small bundles of audio data. Your
interface "speaks" to your computer in buffers,
rather than one sample at a time. The size of these
buffers determine how much delay you hear when
monitoring live inputs through your audio
software: larger buffers produce more delay;
smaller buffers produce less.
Adjusting buffer size on Mac OS X
Under Mac OS X, audio I/O buffer size is handled
by the host audio application (not by your MOTU
interface's Core Audio driver). Most audio software
applications provide an adjustable audio buffer
setting that lets you control the amount of delay
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