MOTU UltraLite- mk3 Hybrid User Manual page 58

Lower latency versus higher CPU overhead
The buffer setting has a large impact on the
following things:
Patch thru latency
■
The load on your computer's CPU
■
Possible distortion at the smallest settings
■
How responsive the transport controls are in
■
your audio software
The buffer setting presents you with a trade-off
between the processing power of your computer
and the delay of live audio as it is being patched
through your software. If you reduce the size, 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 buffer size, you reduce the load on
your computer, freeing up bandwidth for effects,
mixing and other real-time operations.
If you are at a point in your recording project where
you are not currently working with live, patched-
thru material (e.g. you're not recording vocals), or
if you have a way of externally processing inputs,
choose a higher buffer size. Depending on your
computer's CPU speed, you might find that settings
in the middle work best (256 to 1024).
Transport responsiveness
Buffer size also impacts how quickly your audio
software will respond when you begin playback,
although not by amounts that are very noticeable.
Lowering the buffer size will make your software
respond faster; raising the buffer size will make it a
little bit slower, but barely enough to notice.
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.
58
CUEMIX FX HARDWARE MONITORING
The UltraLite-mk3 has a more direct method of
patching audio through the system. This method is
called CueMix FX. When enabled, CueMix
activates hardware patch-thru in the
UltraLite-mk3 itself. CueMix FX has two
important benefits:
First, it completely eliminates the patch thru
■
delay (reducing it to a small number of samples —
about the same amount as one of today's digital
mixers).
Secondly, CueMix FX imposes no strain on the
■
computer.
The trade-off, however, is that CueMix FX
bypasses your host audio software. Instead, live
audio inputs are patched directly through to
outputs in the UltraLite-mk3 itself and are mixed
with disk tracks playing back from your audio
software. This means that you cannot apply
plug-ins, mix automation, or other real-time
effects that your audio software provides. But for
inputs that don't need these types of features,
CueMix DSP is the way to go.
On the other hand, if you really need to use the
mixing and processing provided by your audio
software, you should not use CueMix FX. Instead,
reduce latency with the buffer setting (as explained
earlier in this chapter).
TWO METHODS FOR CONTROLLING
CUEMIX FX
There are two ways to control CueMix FX:
With CueMix FX
■
From within your host audio software (if it
■
supports direct hardware monitoring)
You can even use both methods simultaneously.
R E D U C I N G M O N I T O R I N G L A T E N C Y