Re: microphone stands in the field

["Barry Blesser" bablesser]

The discussion actually has several additional layers of issues.

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.

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 hea=
r
the comb filter response, but we call that natural because we expect to hea=
r
it. However, doing a recording is different from human listening, because i=
n
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 som=
e
binaural processing, or whatever. There are therefore two sets of acoustics=
:
the source space and the listening space.

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.

At least this is my two-cent view of the discussion.

Regards,
Barry Blesser



  -----Original Message-----
From: 
 Behalf Of Steve Pelikan
  Sent: Sunday, December 03, 2006 11:04 PM
  To: 
  Subject: Re: [Nature Recordists] Re: microphone stands in the field



  This is a question I've worried about a fair bit.

  Is this because, by putting the mic well above the ground you're making
the sound reflected off the ground follow such a longer path that (inverse
square law) it has much less energy than the direct path?

  This I understand, but the then same or better effect would be attained b=
y
putting the microphone directly at ground level, since then there'd be no
reflections off the ground?

  Or are you referring to some aspect of sound propagation through the
vegetation near ground level, in which case how does the optimal height
depend on the habitat? (I know and agree with you that the best answer is
"listen and you'll know" but could you offer some guidelines as starting
points?)

  Thanks!

  Steve P