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[1]
How can I optimize my operating system for real-time audio measurements?
You
should eliminate all not strictly necessary programs running
in background. In Windows 95/98 by pressing CTRL-ALT-DEL it
is possible to see all running tasks (at least those installed
by the user). Close all programs and windows then press C-A-D:
the best thing would be to see listed only "Explorer".
In Windows NT4 or Windows 2000 use the taskmanager to see all
running processes and try to close all unnecessary ones. Refer
to the operating system manual to avoid unnecessary tasks automatic
start.
[2]
How avoiding common errors using digital audio cards and improving
sampling result?
The
worst thing that can happen working with digital audio is distorsion
caused by excessive input levels. For musical audio recording
this is a big problem because distorsion caused by A/D saturation
is usually very unpleasant.
The same problem can occur when making measurements with digital
instrumentation.
The suggestion is to monitor constantly the peak level meters
and adjust consequently the input level in the mixer. As a rule,
the maximum peak level should be at least 6 dB above the saturation
level.
Note that in some old sound cards the output section (D/A) can
give some distorsion on the last bit (actually playing signals
greater than 16384=2^14 in absolute value). If you notice this
using Sample Champion, the solution is simple: in Settings|Level
use values<50%.
Fortunately Sample Champion gives you a simple way to analyze
the acoustical performance of your audio card in terms of distorsion
in order to perform a fine tuning of your level settings. See
the application notes concerning this kind of measurements.
[3]
In Sample Champion the wave and the spectrum data seem to "jump"
high and low. What happens?
Sample
Champion has the "Y Auto Scale" option turned on (default).
Simply perform a test measure to let the program measure the
maximum peak amplitude and then turn off the autoscale or, in
a repeated or averaged measure cycle, turn off the option once
that the result of the first measure is plotted.
When the austoscale is off, it is always possible to perform
a manual autoscale by pressing the button on the left of the
autoscale one.
This
page is also available for download as PDF file 
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