Muse Research Receptor TRIO/QU4TTRO manual v1.0 - Manual (Page 35)

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Setup: The "Audio..." settings menu
The Current Audio Device setting lets you select between the two audio interface modes available on
your RECEPTOR. One is for the built-in audio, and one for the bundled PreSonus AudioBox 1818 interface.
The onboard audio is provided for convenience, say in the case where you need to do a quick rehearsal
and don't want to take the PreSonus inteface out of your rack. When you want the best possible audio
quality with the largest number of sample rate and I/O choices, you should connect and use the PreSonus
interface. Selecting which interface you want to use is easy, just select whichever one you want from the
menu selector, and click OK. The host software will restart, and the new interface will be selected.
System Latency refers to how many buffers of audio you are employing to perform all of the various
calculations necessary to turn digital "bits" into music. The plug-ins on your system require a certain
amount of CPU "processing time" in order to generate its sound or effect, and the more plug-ins you run,
the higher the demands on the CPU.
By increasing the number of buffers the CPU has to work with, you reduce the chances that a calcuation
won't be completed in the time allowed, which could result in an unpleasant audio click or pop. Increasing
the number of buffers the CPU has to work with gives it more time to do the work you have given it to
do, which means it can run more plug-ins, or deliver higher polyphony counts with any particular plug-
in. However, by increasing the number of buffers you are using in the processing chain, you are also
introduce additional delay between the time a MIDI or audio signal comes into the system and the time
that you hear the resultant audio. As such, the buffer setting directly affects the system latency which will
determine how "fast" or "tight" your RECEPTOR feels. The more buffers you use, the higher the system
latency, and the "slower" the system feels. The key for the setting is to find the right "buffer size" or
"System Latency" setting for your particular use case to allow everything to work smoothly and efficiently.
The audio menu gives you choice of several different "System Latency" settings:
Lowest (48 sample buffers): This is the fastest setting in the RECEPTOR, and is best for drums
or when you are singing. This is also the most demanding setting in terms of the processor load,
so some presets may not be able to run well at this setting. If you hear clicking or popping in the
audio output while playing at this setting, try selecting the next higher setting.
Normal (128 sample buffers): This is the standard setting in the RECEPTOR. Fast, but not so fast
that you are likely to overload the CPU on a regular basis. If you hear clicking or popping in the
audio output while playing at this setting, try selecting the next higher setting.
Medium (256 sample buffers): Slower than normal, this setting is typical of most computer
systems. Percussive sounds may feel a bit a little slow in their response at this setting but should
be fine for sounds that are more legato, like strings and pad synths. If you hear clicking or popping
in the audio output while playing at this setting, try selecting the next highest setting.
Highest (512 sample buffers): If Medium does not give your RECEPTOR enough time to get its
work done, then try the highest setting. This setting gives the processor the most amount of time
to do its job, and should be sufficient for every sound found in RECEPTOR. If you still hear clicks
and pops at this setting, you might want to try lowering the sample rate or reducing the CPU load.
The Sample Rate setting lets you set the rate of digital to analog and analog to digital conversion in the
system. The built-in audio provides your choice of 44.1 or 48kHz sample rates, where as the PreSonus
interface gives you the choice of 44.1, 48, 88.2, and 96kHz. The faster you set your sample rate, the
more load you are introducing to the CPU (since data is being processed faster), but a faster sample rate
also reduces the system latency: latency is halved with each doubling of the sample rate.
The Sample Clock Source selects what clock source is used in the audio sub-system. The on-board
audio supports only internal clock. The PreSonus interface lets you chose from multiple clock sources:
INTERNAL, S/PDIF (clocking to the incoming S/PDIF stream) or ADAT (locking on to the incoming clock
from an external ADAT input). Note that you MUST have a stable, clean, and valid clock presented to the
system when using external clock mode or your audio quality will suffer greatly.