MOTU 828x 28x30 Audio Interface with ThunderTechnology - Manual (Page 40)

M O T U A U D I O C O N S O L E
40
The TOSLink clock source setting refers to the
clock provided by an optical S/PDIF device
connected to the 828x’s optical input. This setting
can be used to slave the 828x 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 a TOSLink-
compatible device that has no way of
synchronizing digitally to the 828x or an external
synchronizer. In this case, the
TOSLink clock
source setting lets you slave the 828x to the other
device via the 828x’s optical input.
This setting is also useful if you just need to make a
simple, click-free digital transfer between the 828x
and another device — where a time code reference
and shared transport control are not needed —
without having to set up an elaborate synchroni-
zation scenario.
For further details, see “Choosing a clock source
for optical connections” on page 26.
SMPTE
Choose this setting to resolve the 828x directly to
SMPTE time code (LTC) being received via one of
the 828x’s audio inputs. For details, see “Setting up
for SMPTE time code sync” on page 115 and
chapter 10, “MOTU SMPTE Console” (page 113).
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
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 67).
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
or less, if your computer seems to be able to handle
them. If your host audio software has a processor
meter, check it. If it starts getting maxed out, or if
the computer seems sluggish, raise the
Samples Per
Buffer until performance returns to normal.