Samples Per Buffer - MOTU 828 Mk III Hybrid User Manual

connected to another optical device. These two
settings only appear in the Clock Source menu
with their corresponding optical bank input is
enabled and set to the TOSLink format, as
explained in "Optical input/output" on page 39.
The TOSLink clock source setting refers to the
clock provided an optical S/PDIF device connected
to the 828mk3's optical input. This setting can be
used to slave the 828mk3 directly to the optical
input connection. Most of the time, you can set up
a better operating scenario that uses one of the
other synchronization options. However, there
may be occasions when you have an TOSLink-
compatible device that has no way of
synchronizing digitally to the 828mk3 or an
external synchronizer such as the Digital
Timepiece. In this case, the TOSLink clock source
setting lets you slave the 828mk3 to the other
device via the 828mk3's optical input.
This setting is also useful if you just need to make a
simple, click-free digital transfer between the
828mk3 and another device — where a time code
reference and shared transport control are not
needed — without having to set up an elaborate
synchronization scenario.
For further details, see "Choosing a clock source
for optical connections" on page 24.
SMPTE
Choose this setting to resolve the 828mk3 directly
to SMPTE time code (LTC) being received via the
828mk3's quarter-inch SMPTE input jack. For
details, see "Syncing to SMPTE timecode" on
page 29 and chapter 10, "MOTU SMPTE Console"
(page 111).

Samples Per Buffer

The Samples Per Buffer setting lets you reduce the
delay you hear when patching live audio through
your audio software. For example, you might have
a live guitar input that you would like to run
38
through an amp simulation plug-in that you are
running in your host audio software. When doing
so, you may hear or feel some "sponginess" (delay)
between the source and the processed signal. If so,
don't worry. This effect only affects what you hear:
it is not present in what is actually recorded.
You can use Samples Per Buffer setting to reduce
this monitoring delay—and even make it
completely inaudible.
☛
If you don't need to process an incoming live
signal with software plug-ins, you can monitor the
signal with no delay at all using CueMix FX, which
routes the signal directly to your speakers via
hardware. For details, see chapter 9, "CueMix FX"
(page 65).
Adjusting the Samples Per Buffer setting impacts
the following things:
The strain on your computer's CPU
■
The delay you hear when routing a live signal
■
through your host audio software plug-ins
How responsive the transport controls are in
■
your software
This setting presents you with a trade-off between
the processing power of your computer and the
delay of live audio as it is being processed by
plug-ins. If you reduce the Samples Per Buffer, you
reduce patch thru latency, but significantly increase
the overall processing load on your computer,
leaving less CPU bandwidth for things like real-
time effects processing. On the other hand, if you
increase the Samples Per Buffer, you reduce the load
on your computer, freeing up bandwidth for
effects, mixing and other real-time operations. But
don't set the Samples Per Buffer too low, or it may
cause distortion in your audio.
If you don't process live inputs with software
plug-ins, leave this setting at its default value of
1024 samples. If you do, try settings of 256 samples
M O T U A U D I O C O N S O L E