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Re: mic arrays and M/S behaviour

Subject: Re: mic arrays and M/S behaviour
From: "Rob Danielson" danielson_audio
Date: Wed Sep 1, 2010 7:24 am ((PDT))
At 12:27 AM -0700 9/1/10, Luiz do Carmo wrote:
>  Back to Back Crown SASS seemed to be a good
>idea, at least in theory. And it could be
>mounted with the AT4022, considering it looks
>DIY friendly.

SYou can start with Andrew's and Paul's test in
the DIY Boundary Mics blog and go through posts
chronologically to get some ideas:
http://tinyurl.com/29mgcj6


>I still couldn't get rid of my doubt, which
>concerns the cardioid mics that play
>the mids in a M/S array. Do they actually 'sound' or only work as a tool t=
o
>separate (or design) the L and R channels? Because if they do not take par=
t on
>the overall sound after decoding,

Because using phase difference to to encode
"Left" and "Right" seems like a simplification?
Not really, the sound waves are striking both
sides of the figure 8 capsule and all stereo
relies on the brain discerning left-right
differences. Most listeners find M-S stereo
imagery very satisfying.

I can post some Perp2Sphere, SASS- B and Parallel
Boundary imagery from the same location to
experiment with. There are some samples you can
access through the Community FAQ
http://tinyurl.com/2bqxh2w  (Folks can add other
links that Luiz can use or email them to me and
I'll be happy to add them.)

>I could have a pair of MKH-416 or even the way
>less expensive NTG-3, with a NT2-A in the
>middle. Does it sound completely nonesense?

Nothing that sounds good is nonsense. :-) The
only qualification might be on-going interest and
awareness of what stereo and surround imagery is
capable of. Mics/arrays/positioning is what we
do, right?

>About the recorder, I followed the thread
>discussing the DR-680 and got worried
>about the reliability of the software, as far as
>an issue concerning files that
>'simply disappear'. In a feature film it could
>lead to murder. But I didn't give
>up on this machine. I had this recorder already in mind since its release.

I've owned a number of digital recorders that
have preferred ways to be "managed."  Once I
figured out what they were, the recorder became
very reliable for me to use. Sufficient powering
is the #1 field concern no matter what recorder
is used. Based on the whole of the reports I've
read about the DR-680, I think one can use it
reliably. There are some very accomplished sound
for film recordists on this list and some may
have had a DR680 out in the field. Perhaps look
through the

list? http://tinyurl.com/2ewvbm6  Let us know if
you discover chronic issues.

>
>The R-44 looks a little flimsy, but what got me
>not so much excited about it was
>the way it saves the tracks, stocking every single take in a different fol=
der.
>It wouldn't be a big hassle for ambience recording, but for a film set whe=
re I
>record 100 plus tracks in a day it could drive
>me crazy - either to playback or
>during post.
>
>I've also thought about a setup with an interface + laptop - mostly for th=
e
>small issues regarding the DR-680 and the R-44 -, but the noisy pres on th=
e
>M-Audio Fast Track Ultra were not compelling.

Oh, boy. Having done this for two years, I would
definitely advise against it. The list of
possible problems that can crop up is much
longer. I can see how some people could make an
enjoyable ritual out of booting-up in the woods
but it felt too tenuous to me.

Recording longevity is becoming more of a factor
to look at. I love that I can put a 300GB drive
in my 744T and even record to an external drive.
I also love being able to record in .flac.



>Then I heard here about the Motu
>Traveler-mk3, took a look at it and was impressed with the quality of the
>preamps - allegedly great, at least for the reviewers.

The pres in the first Travelers models had pretty
low gain. Not sure about the newer ones.

>
>I believe that I'm researching on mic arrays first, because I'm maybe wait=
ing
>for the release of an FR'4'-LE, which would be the best thing to happen fo=
r my
>budget/expectations.

The DR680 will remain one of the top bargains for a while I'd guess. Rob D.

>I'll keep on researching and thanks again for the help.
>
>Luis
>
>________________________________
>From: Rob Danielson <<type%40uwm.edu>>
>To:
><naturerecordists%40yahoogroups.com>=
m
>Sent: Tue, August 31, 2010 6:46:29 AM
>Subject: Re: [Nature Recordists] mic arrays and M/S behaviour
>
>At 10:51 PM -0700 8/30/10, Luiz do Carmo wrote:
>>
>>Hi,
>>
>>I am a sound professional based in Brazil. At
>>the moment I am working in a film
>>in which the action takes place in a rural environment surrounded by a de=
nse
>>forest. The easy way to work around our low budget enterprise would be th=
e
>>utilization of some (quite some=B7) stereo ambience recordings I have col=
lected
>>over the years, but I lost all of them in a
>>=91computer accident=A9=96 =B0=A9 which is a
>>story longer than what I believe would suit the present occasion.
>>
>>The good part of this tragic story is that it forced me to do something I=
 was
>>procrastinating for quite a while, since I have being inclined to start
>>producing 4 channel recordings for such purpose,
>>but the lack of available time
>>and money kept delaying my plans.
>>
>>After gathering (googled) information around and lately here in this list=
 I
>>ended up with two types of mic arrays that I suppose would work fine in a=
 5.1
>>Dolby Digital final mix, which requires discrete channels: An IRT Cross o=
r a
>>Double M/S.
>>
>>To fit my budget, 4 AT4021 mics in an IRT Cross setup would do it. The on=
ly
>>problem in using the ATs would be the fact that
>>these mics would only be useful
>>=B0=A9 for the kind of work I do: post production
>>and location sound =B0=A9 for ambience
>>recordings (I have Oktava MK-012s for sfx), as they are not suited for
>>production sound/dialogues, which are almost always recorded with shotgun=
s,
>>principally in outdoors situations.
>>
>>My first question is: Do the sound of the mid
>>mics on a Double M/S take part in
>>the overall sound, or the resulting 4 channels
>>only carry the audio information
>>captured by the figure-8?
>>
>>I ask that because if the sound of the figure-8
>>mic is what actually is heard in
>>the 4 channel image, I could use whatever cardioids or supercardioid =B0=
=A9 for
>>example, a MKH-416 or a pair of Oktava MK-012,
>>which I already have =B0=A9 without
>>altering the quality of the figure-8 mic. I could add to this that with s=
uch
>>setup I could have a mic array already set for directional plus surround
>>recording, which would suit perfectly for
>>documentary film situations, besides
>>the adition of easiness represented by a lot less gear to carry around.
>>
>>(The second question is about recorders and I rather leave it for another
>>thread).
>>
>>I would like to thank all the list members for sharing your knowledge, wh=
ich
>>already helped me a lot and specially, for the
>>present matter, Rob Danielson for
>>his microphone chart.
>>
>>Regards,
>>Luis
>
>Hi Luis -
>A belated welcome to the list! Sorry to read about your lost recordings.
>
>If only there was a web site with controlled
>recordings where you could compare the impacts of
>a number of surround array options! Without
>samples, there are many opinions and different
>goals to wade through without reference. It would
>be well worth your time to find and listen to
>actual recordings made in settings similar to
>those you record in. To aid partially in this, I
>can suggest a small work-sharing group that
>focuses on surround recording. You can ask the
>people in this group for links to samples. One of
>the recordists uses a surround array that is a
>variation of an IRT Cross. (Anyone who wishes to
>have their email address added, contact me, off
>list.)
>
>As you are on a tighter budget, I would
>definitely look for field samples made with these
>array types:
>
>Double M-S Arrays
>Back to Back SASS-B Arrays (People are making DIY SASS-B's and variations)
>Spaced Rear Arrays (usually a stereo array in
>front with wide spaced omni's in the rear)
>Spaced Front & Back Arrays (Usually two stereo
>arrays spaced according to habitat(s) and
>acoustics)
>Decca Tree (Greg Weddig comes to mind)
>Holophone (possibly not too hard to DIY)
>
>Harder to DIY arrays:
>Ambisonic Arrays
>Sphere Arrays (Double-MS on a sphere boundary
>like SchoepsKFM 360 or two stereo spheres back
>to back to with a sound-blocking panel in between)
>
>I would not base opinion only on recording
>samples that were made inside or of loud subjects
>. If the "natural ambiences" you want to capture
>become very "quiet" at times, you will want to
>only use very low-noise mics.
>
>As for your recorder question, "Tascam DR680" is
>one answer to investigate. Rob D.
>
>--
>
>
>


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