[I'm not so sure what's so magical about 17cm, ~James]
ORTF stands for Office de Radiodiffusion T=E9l=E9vision Fran=E7aise, and wa=
s pioneered
by French Radio in the 50=E2=80=99s and 60=E2=80=99s. In studying the tech=
nique further, the
reason for the 17cm is that distance most closely approximates the distance=
between the ears of a human.
Now if it=E2=80=99s Pinae to Pinae vs. Eardrum to Eardrum, I don=E2=80=99t =
know, (I think it=E2=80=99s
Eardrum to Eardrum) but I have been using the technique for over 20 years n=
ow.
When capturing 2 channel stereo I utilize the ORTF pickup pattern for all o=
f my
recordings. The reason is, the ORTF coincident pickup pattern sounds most =
like
what I hear in the real world.
Human ears hear the frequencies 1.5kHz to 3.5kHz most predominantly at 55
degrees off axis from the center of the nose (0 degrees) at 10 degrees of
elevation. When I use (or am forced to use) X-Y, Blumlien, Jecklin discs, =
and
the like, I am never as happy because the natural soundfield does not repro=
duce
as accurately as I first heard it.
Spaced omni=E2=80=99s are different because they use a different principal =
than
coincidence. While M/S is also a coincident technique, the idea of mapping=
the
soundfield to a likeable width, is also a different recording style. It=E2=
=80=99s more
like sound design than accurate capture.
It=E2=80=99s very similar to Binaural except that there is no =E2=80=98body=
=E2=80=99 to introduce HRTF=E2=80=99s
(Head Related Transfer Functions) or to essentially give greater separation=
between the microphone pickup patterns. Binaural mics are most often Omnis=
,
necessitating a boundary for separation between the diaphragms.
The ORTF system utilizes cardioids as a means of directivity, thereby negat=
ing a
need for a boundary layer between the elements. I have used sub-cardioid
capsules in my ORTF setup, but the low-end response was thrown completely o=
ut of
whack when I tried this (far too much low-end rumble). But it might help w=
hen
trying to capture waves.
~Marcus
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