[Sebastian Kaliszewski]

Audio Empire wrote:
On Sat, 30 Apr 2011 07:56:56 -0700, bob wrote
(in article ):

Friday night, WQXR in New York broadcast a live concert by Orpheus
Chamber Orchestra at Carnegie Hall. On their Web site, it was possible
to get a binaural stream. I wasn't able to listen to it (my wife
wanted to hear the concert too, so no headphones!), but was wondering
if anyone else had.

I gather this is a fairly new feature, and I don't know if they're
going to do it on any upcoming live broadcasts.

bob

I certainly would have listened-in had I known about it. I used to do
binaural broadcasts for the now defunct KPEN Classical Station in Mountain
View, CA. and they were very well received. In those days I made my own
binaural set-up with a styrofoam wig stand, a pair of Neumann KM-83
"lipstick" condenser omnidirectional condenser mikes (alas, they weren't
mine, they belonged to the station), and a piece of wood with a 1/4-20
captive nut hammered into it.

I buried the KM-83s in each side of the styrofoam head after "painting" it
with a can of "flock" paint from an auto supply store. The microphones were
situated with the diaphragms flush with, and parallel to, the sides of the
"head" . The board was cut with a scroll saw to neck-size and glued to the
bottom of the head with the captive nut centered for mounting the head on a
camera tripod. When the recordings were played back through headphones, the
effect was almost spooky. The only thing that I could never get binaural to
do was to localize things in back of one's head. A test was to walk around
the head while it was being recorded jiggling a set of keys. Images were
solid and localization pin-point anywhere at the sides of the head, or in
front of the head, but images from behind seemed to move to the middle of
one's head, halfway between your two ears (the way regular stereo often
images on headphones). I could never figure out how to get binaural to place
images behind the listener. I suspected that it might be because the
recording head had no external ears but when I tried to fabricate a pair out
of a piece of leather, the rear imaging didn't improve, yet we all know that
we can always tell when sounds are behind us. 'Tis a puzzlement to this day.
But with music recordings where the instruments are arrayed in front of the
head, nobody ever seemed to notice.


Because in fact if one keeps ones head still one has trouble distingushing if
the real physical sound source is behind or in front of ones head. We, humans,
get some clues from spectral differences if we're well acustomed to particular
sound and that particular sound has proper frequency contetnt to be detectable.

In student times we (me and my friends) made simple unsceintific experiment to
verify if that above statement is true (trouble with detecting if sound is
exactly behind or excatly in front ones head). One (test participant) got
blindfolded then sited on a chair and rotated few times. Then one of the others
put some very low end portable cassette player (those devices were so terrible
that they got popular name which would be translated to English as "consumptive"
-- that was in fact a play on the real name of the thing) exactly behind or
exactly in front of the participant and turned it on. Participant was to point
out if that sound source was in front of or behind their head without turning
their head. Results were null.

Unless one could turn his head, ones anwsers were not different that pure
chance. Interestingly once that device was about 30degree off to the side (still
mostly behind( recognition was 100% acurate.

rgds
\SK
--
"Never underestimate the power of human stupidity" -- L. Lang
--
http://www.tajga.org -- (some photos from my travels)