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Re: ORTF Recommendations

Subject: Re: ORTF Recommendations
From: "Marcus Buick" mbuick
Date: Thu Aug 26, 2010 3:01 pm ((PDT))
[Hi Marcus-- Welcome to the list. I appreciate that you want your stereo ar=
rays
to
emulate field experience.  ~Rob]

Thank you, Rob.

[(1) Mic positioning is factor #1 and is best done in sympathy with
local acoustics.]

Absolutely.  Without question.

[(2) That all stereo mic arrays have strengths and weaknesses and that
none capture human (listening-processing) experience adequately.]

I agree about strengths and weaknesses and it=E2=80=99s true that no stereo=
 mic array
captures what humans hear.  To the defense of stereo array=E2=80=99s howeve=
r, we must
conclude that utilizing the most reference technology gives us our basis of=

understanding and thus gives us an adequate experience by which to judge.

[(3) That stereo imaging is highly dependent on monitoring used and
that speakers and headphones are very challenged to present universal
reference.]

Image is dependent on reproduction (and the acoustical space that reproduct=
ion
system lives in).  I find speakers to be like microphones.  Pick the color =
you
wish to paint with.
Headphones/Earspeakers are a very personal choice and while no universal
reference exists, common perception can allow people to agree and collabora=
te.

[(4) It helps to get mics up in the air-- further away from nearby
surfaces when imaging space (not withstanding boundary arrays).]

Every boundary that creates acoustic signatures affects microphone pickup
pattern, coloration, and image.  The more free field a pickup pattern exist=
s in,
the more accurate the capture.  With the ground being the largest and most=

predominant boundary we are saddled with, I agree getting the mics up in th=
e air
helps with the image, but then wind usually becomes a greater factor of con=
cern.

[(5) Spaced arrays tend to create impressions of spaciousness more readily =
than
coincident arrays.]

Indeed this is true.  The only thing I love more than ORTF are spaced omni=
=E2=80=99s.
When spaced omni=E2=80=99s are done right, the bass response captured can t=
ruly move the
soul (or create bone-conduction that can move bodily organs!)

[(6) Stereo imagery created with stationary arrays can possess more subtlet=
y.]

And less image shift, signal attenuation, and movement born vibration.

[(7) Successful surround imagery begins with understanding stereo imagery.]

Yes and I do believe that theory and practice are of equally relevant impor=
tance
for both.

[(8) M-S processing is a powerful option that can be explored with any
stereo recording in post.]

Indeed, as has been discussed earlier in this thread.  Also, re: (9), a per=
fect
example of when M/S is better than any other coincident technique.

[(9) Positioning localized, low frequency sounds (<~125Hz) in the center of=
 the
stereo field creates more options in post production compared to side
positioning.]

I think in theory this is correct, however, because low frequency sounds ar=
e
omni-directional, the SPL of the low frequency content is probably of more=

concern.  In post I would prefer a louder low frequency in one mic, than a=

centered, barely audible, low frequency signal in both.  Because the abilit=
y to
center an image in post is easy, I would focus my efforts on capturing the=

greatest amount of low frequency content in the field and worry about the i=
mage
later.

(10) That stereo imaging can involve active participation on the part of th=
e
listener. Thus, a recordist gets "better" at processing the "cues" provided=
 by
the arrays she/he uses.

Absolutely!  It=E2=80=99s the reason I love my Schoeps so much!

An interesting side note:  a paper written by Eugene Brandewie and Pavel
Zahorika, in the JASA titled, Prior listening in rooms improves speech
intelligibility, indicates that acoustic effects of a single re=EF=AC=82ect=
ion are
perceptually suppressed after repeated exposure to a particular con=EF=AC=
=81guration of
source and re=EF=AC=82ection.


Results from14 listeners indicate that with prior room exposure, masked spe=
ech
reception thresholds were on average 2.7 dB lower than thresholds without
exposure, an improvement in intelligibility of over 18%.


This effect, which is shown to be absent in anechoic space and greatly redu=
ced
under monaural listening conditions, demonstrates that prior binaural expos=
ure
to reverberant rooms can improve speech intelligibility, perhaps due to a
process of perceptual adaptation to the acoustics of the listening room.

I believe this effect is also present when listening to music or any comple=
x
recording, and the inverse of this seems to be true as well, i.e. that with=

repeated exposure to any recording process, the listener=E2=80=99s ears hea=
r more of
what they want their mics to capture, than everything the mics actually =E2=
=80=98hear=E2=80=99.
Basically what you said Rob, that a recordist gets "better" at processing t=
he
"cues" provided by the arrays she/he uses.





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