MOTU 828 User Manual page 61

Effects processing and automated mixing
Reducing latency with the buffer size setting has
another benefit: it lets you route live inputs
through the real-time effects processing and mix
automation of your audio software.
LOOPBACK
Use the Loopback In 1-2 input channels provided
by the 828 audio driver to send USB audio output
from your computer – or any 828 mix – back to
the computer.
Choose the desired source from the Loopback
Source menu (item #12 on page 46).
The loopback channels return the chosen signal
back to the computer so that you can capture the
signal in your host software, stream it to the web
or broadcast it with podcasting software.
Loopback location
The Loopback Location setting (item #4 on
page 43, and below in Figure 7-6) determines the
placement of the loopback channels within the list
of input channels available in your host audio
software. There are two choices, as shown below.
Figure 7-6: Loopback location.
The default location is USB In 9-10, which is just
after the eight analog input channels. Alternately,
you could choose USB In 1-2 (the first two
channels in the list).
If your host audio software presents all 828 input
channels in its UI (wherever input channels are
displayed), then this setting is mostly comes down
to personal preference. However, some host audio
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
applications don't provide a way to choose from
among several input channel pairs, or they can
only present a few choices for input channels. This
can especially be true for video-conferencing or
podcasting-related applications, for which the
loopback feature is crucial. In cases like these,
choosing the USB In 1-2 option guarantees that
the host software has access to the loopback
channels because they are the first channels in the
list, which may be the only two channels that the
software can access.
Mixing loopback with live inputs and disk tracks
If you need to mix the loopback channels with live
inputs, do the following:
1 Choose a mix from the Loopback Source menu
(item #12 on page 46).
2 Go to the mix tab for that mix (item #1 on
page 47) and bring up the fader(s) for the
computer USB channels you want to hear.
3 Bring up the faders for any live inputs you want
to add to the mix. When you do so, their signal is
mixed with the computer USB channels.
Remember, be careful! When monitoring
loopback channels and live inputs, your host
software can cause loud feedback loops. Be sure to
disable the monitoring of loopback tracks to avoid
feedback.
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