For its one small chapter on the fundamentals of outdoor sound
propagation I found the following book quite useful:
Handbook for sound engineers / Glen M. Ballou, editor
Boston, Mass.; Oxford : Focal, 2005, c2002.
3rd ed.; paperback ed.
ISBN 0240807588
I check it out now and then from the local library, though I would
love to own a copy - so if anyone finds a used one somewhere for
cheap, please let me know.
Having a basic understanding of theoretical effects of reflection,
refraction, diffraction and diffusion, and how they relate to the
natural recording environment including ground surface, topography,
foliage, temperature, wind, (and whatever else) can be helpful when
searching for the desired recording location or at least for helping
understanding the recordings after the fact.
Depending on the conditions and what you are trying to record, mic
placement could be better up high or down low (though personally, for
most of my recordings I put my mics at chest height or higher.)
One thing for sure is, natural soundscape recording has little to do
with the average height above the ground of the average human head =96
except for convenience which definitely counts for something.
John Hartog
--- In Walter Knapp <> wrote:
>
> Posted by: "Barry Blesser"
>
> > First, there is no question that an elevated microphone will
produce a comb
> > filter frequency response because the direct signal will merge with a
> > delayed version that bounces from the ground. One observes the
same issue
> > with office speakerphones where the microphone is as close to the
table top
> > as possible, thereby avoiding the delayed reflection from the
table top.
>
> In the natural environment you are dealing with direct and reflected
> sound no matter where you put the mic. By putting it up high you avoid
> some of the reflections, particularly those that will have reflected
off
> something close to the mic location and be louder than those reflecting
> off parts of the environment farther away.
>
> The reflections are not as regular and organized as those off a table
> top or floor, however. So calling it a comb filter is probably not
proper.
>
> > Second, the question of what constitute "natural" pops up. As adults
> > standing in the field, our ears are some 5 feed above ground and
we too hear
> > the comb filter response, but we call that natural because we
expect to hear
> > it. However, doing a recording is different from human listening,
because in
> > the first case, the sound source and the listener are in one shared
> > environment. When reproducing a recording, however, the listening
> > environment may be stereo loudspeakers in a laboratory, headphones
with some
> > binaural processing, or whatever. There are therefore two sets of
acoustics:
> > the source space and the listening space.
>
> Indeed, one can make a case for only recording at standard ear height
> and only with ear spaced microphones. However, microphones are not
ears,
> and definitely don't have the processing system we have behind them. We
> process and simplify sound before we hear it. Even so far as
selectively
> removing reflections from individual reflecting objects. Dropping a lot
> of the original sound sources entirely. Microphones don't do any of
> that, and part of the challenge is to get them to duplicate in some way
> our filtration of sound. One way is to simplify the soundfield with
> height of the microphone. It is not the only way.
>
>
> > The same issue appears when trying to record music. Even though the
> > applications and goals are different, the discussion about musical
space in
> > my book, Spaces Speak, is directly relevant to all forms of
recording. One
> > must carefully analyze the choices in the context of the specific
goals.
>
> As I've pointed out music is recorded in specifically simplified
> environments with regular and organized acoustic features. Nature
> recording has no such luxury.
>
> Actually, nowadays music is often a mixture of a bunch of mono mic
> pickups picking up individual instruments or groups of instruments
mixed
> to imitate a organized soundfield. Nature recording rarely tries this
> but depends on much simpler pickups that preserve the natural cues of
> the soundfield. At least that's how I approach it, one recordist, one
> stereo mic setup to record the soundfield. It's quite different from
> current music recording.
>
> And that's even without considering the differences in scale. Nature
> recording deals with far greater distances than music recording. Which
> makes for considerable difference in technique.
>
> Walt
>
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