[Audio Empire]

On Mon, 27 Jun 2011 19:28:50 -0700, Gary Eickmeier wrote
(in article ):

"Audio Empire" wrote in message
...

I think you need to study-up on how humans localize sounds. It is done by
a
combination of level differences and phase differences. Spaced omnis
locate
sounds within soundstage by colume differences between right and left
only.
The lack of phase coherence actually confuses those cues. I can tell a
spaced
omni recording every time. It's as audible to me as multi-miking (but not
nearly as annoying)

Not to be argumentative - I agree with your basic points about
experimenting - but just food for thought. No, I don't need to study too
much more about how we localize sounds. I have been at this for some 25 or
30 years now, at an amateur level. Stan Lip****z wrote a famous article some
years back about "Stereo Miking Techniques - Are the Purists Wrong?" The
gist of it was that microphones do not need to hear the way humans hear.
When we play back a recording, no matter how it was recorded, the various
sounds will image somewhere within the stereo field by intensity or phase,
doesn't matter, and we will use our natural hearing mechanism to localize
sounds the same way we would live. He compared Blumlein stereo to pan-potted
multimike techniques. I must look that article up again.


See above. The mono compatibility is not important, per se, but it does
point
out rather dramatically that spaced omnis have serious phase problems and
it
shows, without question, how wrong-headed the spaced omni method is. To
me
it's a serious compromise and I admit readily that I don't understand what
seems to be your blind adherence to it. When I was recording a wind
ensemble's (symphonic band) rehearsals I tried all kinds of microphone
schemes - including spaced omnis. If you could hear the difference in
soundstage and imaging between the three spaced omnis and the X-Y or M-S
stereo versions, I dare say you'd never use former again. The palpable,
almost holographic imaging of the X-Y and M-S recordings is startling
while
the spaced omnis is much more vague and amorphous.

My only real point in this discussion is that one should experiment with
different mike placements and methodologies before drawing any
conclusions.
It's the only way to KNOW what works best. If you try all the different
setups and still find that you prefer the three spaced omnis, then go for
it
and don't let anyone tell you differently, because you'll know, from
actual
experience, what kind of results they all yield.

I have only begun doing just that. I recorded my current batch with both the
spaced omnis and a single point stereo mike. But I was so thrilled with the
spaced omni results that I never did do my comparison.

The impetus for my acquiring the R16 multitrack recorder and enough mikes to
make the experimental recordings was my experience with the single point
mike. It just didn't have enough space or stereo spread to it - almost a
mono recording.

Then you didn't do something right. Stereo miking will work with cardioid or
figure-of-eight mikes, but not with omnis. Use omnis and you WILL get mono.

But besides that, in my basic paper on stereo I reasoned at
the end of it that since my ideal playback system was three spaced speakers
attempting to reconstruct the image model of the live sound field, and since
the playback image model was an orthographic projection within the
rectangular space, the correct way to capture the live model of direct and
early reflected sounds that exist in the concert space would be to position
microphones near those images. I suggested some simple math that tells me
how close I can position the three mikes to the performers to get a
perfectly even spread all across the soundstage. You could also use 5 spaced
omnis to get even more differentiation. The main point, however, is that in
order to get all of the direct and reflected sounds onto the recording, the
recording engineer must remember that he is making two stereo recordings at
the same time: the musical instruments themselves and their early reflected
sounds.


But you haven't compared different techniques on the same ensemble to find
which is better. I'm sure that your recordings sound fine. The old
Mercury
Living Presence and RCA "Red Seals" made with three spaced omnis sound
very
good. They are still among the best recorded classical performances ever
released. But they could have imaged so much better had Bob Fine and Lewis
Leyton, et al used a stereo pair of modern cardioids or an M-S setup
instead
of the three spaced omnis. For contrast, listen to one of John Eargle's
Delos recordings of Gerard Schwarze and the Seattle Orchestra. Eargle used
M-S miking. Wow! What palpable, you-are-there soundstage and imaging!

But yes, I have, but haven't carried the experiment all the way through
yet. I am going to record a chamber orchestra on the 7th of next month - my
daughter's orchestra camp has a final concert every year. It will be in an
ideal medium size room. I hope to get a piano trio or quartet somewhere,
somehow, in the near future to try it on that as well.

Eargle used omnis outboard of the center stereo mikes to get some space into
his recordings.

That was for hall ambience, and it can certainly work well that way as long
as the auxiliary omnis are subordinate to the stereo pair. I've done that
myself and was most pleased with the results. I recently recorded a solo
piano in a (closed at the time) winery. I used the stereo mike directly on
the piano and two omnis at the other end of the hall near (but not in) the
corners. The space was palpable.

I generally agree with your approach of experimentation. I don't have as
much experience recording as you do, but I imagine another difference is our
playback systems. Do you lean toward a direct field approach with your
speakers?

No. I use Martin Logan Vantages about 10 ft way and about 7 ft apart.

One last, annoying point. The simplest thought experiment I can offer is
three performers across the soundstage, positioned as your speakers will be.
Example A, suppose you close-miked them and played them back on their
respective speakers. Each speaker represents a single performer on your
soundstage. Imaging is quite perfect, because there they are right where
they belong, unmistakably coming from right, center, and left, listened to
with your natural human hearing just fine. Phase has nothing to do with it.
Example B, suppose we use three spaced omnis to record them. Not much
difference, and still no problem with "phase." Each mike will record some
leakage from the other performers, but that leaked sound will be later in
time, and so will not hurt the imaging from that performer's primary
microphone a bit.

Yes but that's multi-miked mono. Lots of small jazz ensembles are,
essentially miked that way.

I may be able to do some experimental voice tests next time as well, with me
calling out my position on the stage and moving around. I live and learn.

Gary Eickmeier