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Apples with Apples
By Pat Brown
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It can be said that the most fundamental process regarding the reception
and evaluation of sound is that of comparison. Any description of
fidelity or the lack thereof must be in reference to something.
An audio system that amplifies the sound without producing any changes
or distortions continues to elude designers. Most all categories
of system components have their golden makes and models
that the performance of all other components is compared too. But
even these standards arent perfect, and relatively
few people have them available for use in evaluating other products.
A very meaningful and more accessible method of comparison can
be achieved with a number of PC-based analysis tools. Two or more
audio or acoustic measurements can be compared to a great degree
of accuracy with a few keystrokes. This can allow the differences
between audio components to be determined and documented.
I used the Goldline TEF2OTM to perform some comparisons of acoustical
measurement microphones. The testing session was initiated at the
request of Brad Nelson of Sound Solutions Northwest. Brad had the
misfortune of dropping his B&K 4007 measurement microphone.
Since repairs on such a mic can easily exceed $1000, he asked me
to perform a comparison between his mic and my own 4007 - a treasured
possession that I acquired from Syn-Aud-Con founder, Don Davis.

I used a studio monitor as the acoustic source and made a measurement
to use as a reference. Once stored in memory, this measurement becomes
the benchmark that the next measurement (substituting the other
mic) is compared too. Two identical mics would produce a fiat line
in both magnitude and phase. While this is never achieved in the
real world, one would expect microphones of B&K caliber to compare
vary closely.
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