From: Curt Olson <>
> I've used cardioids extensively over the years, mostly in the studio
> but also in the field in XY and ORTF arrays. But I've never worked much
> with omnis, thus my current line of questions.
I have found that the infinite space and extreme acoustic variability of
the outdoors make studio "rules" not necessarily work the best, or have
to be modified. At least that's what I've found working stereo in the
field. I'm convinced that the optimum mic setups for nature recording
have yet to be found, there's room for a lot of experiment.
The field also has it's own new limitations to impose. Like portability.
I prefer that every mic setup I have be easily hand held. This makes
moving through the brush easier, and following a moving caller easier.
The only real exception I make is for my high tripod technique as my
arms are not 15' high and carting a large step ladder is a bit impractical.
The effect of wind is also a major consideration in nature recording.
Whatever arrangement of mics you have it needs fairly good wind
protection. Some mic arrangements are really hard to protect.
While I've experimented with the various traditional arrangements of
spaced omni mics, I keep coming back to the SASS. More and more that's
the only place my pair of MKH-20 are used. It's hand holdable, very
portable, relatively easy to wind protect. And it produces a excellent
stereo field.
>>> For recording "wrap around space," mounting the capsules so that they
>>> point away from each other tends to work better than the typical A/B
>>> "front" facing. The later is used when a portion of the field is of
>>> greater interest. Birders, for example, might like A/B front facing
>>> better.
>
>
> I experimented with both arrangements last week, and found that I
> preferred the capsules facing forward. I'm thinking that it better
> approximates ears, which have an omni pick-up pattern, but a
> forward-facing collector.
That would somewhat depend on the rest of the arrangement. For instance
in the SASS setup having the two boundaries facing forward is unlikely
to work near as well as the current angled version. The SASS as it sets
gives you a "wrap" of about 270 degrees though the cutoff is not sharp.
I have thought of building a back to back boundary setup, but I'm pretty
sure it would be hard to get a good center with two mics that way. It is
the way the Telinga does it's stereo.
>>> For "typical" stereo living room playback, room
>>> architecture/furnishings often dictate speaker locations. Some people
>>> experiment with placement options, but they're probably using tight
>>> field music when they adjust to taste. When we start guessing what
>>> omni mic spreads will work best for living rooms, it might be
>>> realistic to account for speakers that are too close (within 3') and
>>> way-too-far-apart, like in the corners of a large room.
>
>
> And that's the crux of the problem -- accommodating many possible
> playback environments. As with all things audio, it's like nailing
> jello to the wall.
Playback is only part of it, and the easy part at that. The environments
you record in are extremely variable in their sound distribution. The
bottom line is that no one mic setup is best for all. You end up with a
set of mic setups, and a understanding of the sort of source volume each
is best at recording. Kind of similar to photography with a set of fixed
focus lenses, although you don't want to carry that comparison too far.
I typically carry two SASS, three M/S setups, plus the Telinga with it's
stereo mic element. Plus some other odds and ends (like hydrophones).
Making all those diverse stereo volumes fit to a single playback volume
is more or less what this is about. And still having them sound somewhat
like the original.
> Good suggestions here, Rob. There's no end to the experimentation one
> can do. That's a big part of the enjoyment. For example, yesterday I
> stopped in to a nearby salvage store. There I found a bin full of
> high-density foam "bumpers" -- cylinder-shaped, about 4.75" in diameter
> and about 4.5" long, with a .75" hole through their length. In another
> bin were wooden dowels that happened to fit the hole almost exactly. So
> this morning, with $.50 worth of material, I cobbled together a simple
> "head-like" array that upon first impressions sounds absolutely
> stunning. If that impression holds up through some additional testing,
> I may have to go back and buy up a large quantity of the stuff. (And I
> haven't even begun to tinker with parabolas! I'm watching Rich's latest
> reports with great interest.)
One thing to be sure and do with "stereo" experiments is examine the
accuracy of the stereo field. Many setups give something that sounds
stereo, but is actually very irregular in it's locational accuracy. If
it has any at all.
A simple way is to get out where there are plenty of callers in all
directions. Listening to the field with headphones check how well you
can point to each caller. A more lab like approach is to walk around
with some little soundmaker in the field and check the movements in the
recording. You are checking how well the field you hear relates on a
dimensional and angular basis to the real field.
With the advent of mixed/panned multi-mono recordings the true meaning
of stereo has become blurred. It would have been good if there were two
terms, one for the true and accurate recording of a 3d space, and a
different one for the artificial mixed creations and "sound like 3d"
recordings.
Walt
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