Octet Matrix Audio DE5B-DW50 User Manual - page 11
Page 11
Copyright© 2011 Octet Matrix Audio
Highest Output Source
1) You should have a voltmeter or a computer with a soundcard* in order to determine
which source has the highest output level for a given input signal. You do not need a
calibrated measurement system because you only need to determine the relative
output of each source with a known signal (the Octet Matrix Audio 0 dBFS test tone).
If you have a voltmeter, play track 5 through each source and measure the voltage at
the source output. The source output that registers the highest voltage is the source
you should use for the dynamic range optimization setup. If you do not have a
voltmeter, you can download one of the audio level meters in the Resources section
to a computer with a soundcard (preferably a laptop).
2) If you want to skip the technical nonsense and trust your ears, make a copy of the
Octet Matrix Audio Test CD and play Track 5 in two sources at the same time. Set the
Main System Volume to ¼ volume and switch the source selector from one source to
the other to determine which source sounds louder for a given Main System Volume
setting. The source with the highest output should be used for Dynamic Range
Optimization.
*
Any AC voltmeter or PC soundcard will do. You will be measuring sine waves and are interested in relative levels, so it
doesn’t matter if your meter is an RMS responding meter or an average responding meter, or even if it’s out of calibration. If
none of this makes sense to you, don’t worry. The relative values you measure with anything other than a truly broken
meter or soundcard will give you the results you need.
Maximum System Level
The first step in optimizing the wireless system dynamic range is the most difficult;
determining the correct Maximum System Level. The 0dBFS 1 kHz test signal ensures that the
source (CD player, DVD player, Blu-ray player, PC soundcard, or MP3 player) is outputting its
maximum analog level. The difficulty comes when that analog signal is amplified through a
receiver or amplifier. We may want to set the receiver or amplifier volume all the way up,
believing that this should be the Maximum System Level. The problem with this approach is
that with most source output levels, almost no receiver or amplifier will output a clean,
undistorted signal when set to its full output. Without specialized test equipment, the
Maximum System Level must be determined by a suitable source signal and listening. Two
approaches are provided for determination of the Maximum System Level: