Dan, Raimund, Justin,
The first scientific lesson I was taught some 60 years ago, was that
any statement had to be quantitatively validated. If the data could
not be expressed as a number, it was not valid (trans. science), not
fact.
Until recently, around 2000 or 2001, the model for measuring events
within soundscapes involved a profound deconstruction of the component
parts. The general paradigm held that when abstracted to the detail
that single species' traditional measurements could be made,
articulated, peer-reviewed, and published, the science was acceptable
and noted. That archetype began to shift with some of the National
Park Service studies we were commissioned to do in 2001 along with our
colleagues from Michigan State University's Envirosonics Lab (then
headed by Stuart Gage).
The natural soundscape (biophony) is a very complex mechanism. The
acoustic expression, itself, is just now being studied as holistic
systems and several new publications are in the works. But remember
Paul Shepard's admonition: "Nature is slow to reveal her secrets."
Understanding the world of sound is relatively new to this culture
because we rely more on visual cues to understand life around us. One
of the most frustrating problems, aside from new types of
measurements, is the lack of language to express acoustic phenomena.
For instance, when we use the expression, "timbre," we open up a whole
can of worms because it relates to a qualitative expression in music,
an aesthetic call. Yet it is the best word to describe certain kinds
of effects anthrophony has on the biophony, particularly the cause. So
I've tried to hedge the bet by beginning to classify sound into types
and classes, each with a measurable (and thus quantitative) range of
characteristics. Given new analysis software, this is now much easier
to do. I can show, for example, utilizing streaming spectrograms, the
precise effect of human noise on a given biophonic system. From that,
all kinds of data can be abstracted. This wasn't possible until just a
couple of years ago. While the mechanisms are not exactly new to
academic researchers, they've been pretty much overlooked because
there was no precise way to get a grip on what they were seeing/hearing.
New studies are in the works, Raimund. I've been working on one paper
(co-authored with two colleagues from Purdue) soon to be published and
I know of several others where the data are now being analyzed. They
include just the issues that are being addressed in this forum.
Bernie
On Mar 16, 2009, at 12:48 AM, Raimund Specht wrote:
> --- In Dan Dugan <> wrote:
> >
> > > in some of our work, we found evidence that loudness of a
> particular
> > > sound classified as noise didn't have nearly as pronounced an
> affect
> > > as the way the noise was perceived (in our case, recorded). Where
> > > amplitude of the noise had no effect on the biophony, a much
> softer,
> > > but more complex class of sound, did. In my post yesterday, I
> > > described that an F-16 jet flying over a caribou herd with
> > > afterburners blazing had no aversion effect, but that the
> "noise" of
> > > someone approaching the herd on snowshoes most definitely would.
> >
> > Bernie, this is what drives me crazy about those academic
> > bioacousticians who want to reduce everything to dBA readings. So
> far
> > as I'm concerned, absolute levels of nature sounds are pretty much
> > meaningless. It's the nature of the sounds that counts.
> >
> > The challenge for those of us who want to influence the academics is
> > to develop new types of measurements that reflect what's important.
>
> Dan,
>
> I think that we have to distinguish between studies that try to
> investigate the mechanisms of the acoustic communication between
> individuals of the same species (which I believe is what Travis is
> doing) and studies that deal with aversion effects.
>
> I fully agree that the aversion behavior of a caribou herd must be
> triggered by the quality of the sounds, while the absolute sound
> level is almost irrelevant. The animals just know that a continuous
> broad-band noise does not represent a danger to them, while a soft
> crackling noise could represent a dangerous predator approaching
> them. I guess that these mechanisms are not new to academic
> researchers...
>
> Raimund
>
>
>
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