# Re: AUDITORY Digest - 8 Aug 2002 to 9 Aug 2002 (#2002-125)

```Pawel

You have used what mathematicians refer to as the "total variation" of the
spectrum and normalized it by the sum of the ranges. One important use of
total variation in mathematics is in the definition of functions of bounded
variation. A reference is "Principles of Mathematical Analysis," Walter
Rudin, McGraw-Hill 1964.

David

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Subject: AUDITORY Digest - 8 Aug 2002 to 9 Aug 2002 (#2002-125)

There is one message totalling 47 lines in this issue.

Topics of the day:

1. How to call this measure.

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Date:    Fri, 9 Aug 2002 14:08:30 +0200
From:    Pawel Kusmierek <pq@NENCKI.GOV.PL>
Subject: How to call this measure.

Dear list,

I had to compare spectra produced by three different loudspeakers.  I
played white noise through the speakers, recorded the outpput to
computer and made 1/3 octave spectra.

In order to compare them quantitatively, I calculated a measure which
decribes whether the spectrum goes monotonically up from lowest band
to a maximum and then down to the highest band, or it wanders up and
down (has troughs and peaks).  Now I do not know how to call the
measure.  My best idea so far is 'spectrum irregularity'. Can anyone
suggest a good name?

Here is desription how it is calculated (from the manuscript):
Moreover, [NAME] measure of the spectra was calculated as the mean of
the absolute differences between neighbouring 1/3-octave bands.  This
measure was then normalised by dividing by the sum of ascending and
descending vertical (sound pressure level) ranges of the spectra.  The
ranges were computed by subtracting the value in the first band and
the value in the last band, respectively, from the spectrum maximum.

Best regards,

Pawel
=================================

Pawel Kusmierek
Department of Neurophysiology
Nencki Institute of Experimental Biology
3, Pasteur St., 02-093 Warsaw, Poland

tel. (48-22) 659 85 71 ex 379
fax  (48-22) 822 53 42
E-mail: pq@nencki.gov.pl
or: kusmierek@yahoo.com, pq@poczta.gazeta.pl
ICQ 11740175

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End of AUDITORY Digest - 8 Aug 2002 to 9 Aug 2002 (#2002-125)
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