Greg Weddig wrote:
> For ambient soundfields a mono signal can be achieved simply by using
> only one channel. Then you have no worries about phase cancellation.
This is fine for your own mixing, but not for the end user.
And if you use a spaced array, either mic will be off to one side of
your central subject. Maybe by a ways, depending on spacing.
> There are also volumes written on which stereo setups work best when
> played back through headphones or speakers.
And if you start comparing what's said, lots of difference of opinion.
> For my ambient recording I find I get the richer soundfield from a
> ORTF array than a M-S arrangement. I have yet to experiment with a
> spaced array, as Walt said it can be difficult to setup/transport in
> the field.
The main problems with ORTF over MS are in it's being much more
difficult to shockmount and wind protect. And that your center subject
is being recorded 55 degrees off axis. With a quality cardioid, the off
axis is probably not too bad if your central sound is fairly low
frequency. A MKH40, for instance has about 3dB difference between high
and low frequency at that angle compared to it's on axis pickup.
I'm finding that proper shockmounting and wind protection is a big deal
in what's possible. A number of setups are virtually pegged to calm
conditions by this.
MS done with a cardioid mid actually is the equivalent to two cardioids,
with the angle adjustable in the decode stage. So, you can do the
equivalent of the ORTF array in MS. Part of the problem with MS is that
you do have so many options when decoding, and these can have
considerable effect on the sound. You also have only a limited choice in
figure 8 mics, vs a almost endless selection of cardioids.
My feeling is that for a spaced array to record a wide soundfield in
nature recording you are probably going to end up with two mic stands.
Rather than trying to do it on a stereo bar.
The transport and setup problems are probably why you rarely see anyone
using widely spaced omnis in nature recording. Coincident and near
coincident setups have lots of advantages for portability by comparison.
Walt
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