Hi Graham,
Your project sounds really exciting. I love the idea of a
visitor strolling through the sculpture garden with open-air
phones or earbuds, listening to the dialog, and occasional
Foley. If the phones are open-air, the visitor may end up having
no idea the Foley isn't local live sound. The possibilities are
delightful!
To go into your other questions, in perhaps more detail than you
wanted...
The NT-1As handle rather high spls, and are also extraordinarily
quiet, and are also high output, which is a super combination of
qualities for ambience recording and a lot of other situations.
They may not be the most accurate mics in the world, but they
are one heck of a good deal.
However, as Rob pointed out, they're cardiod, and so they're not
as suited for 360-degree ambience capture. Omnis will always be
more appropriate in that situation IF you're limited to two
mics. Then you can start exploring arrays, cubes, dodecahedrons,
etc. (And a second dayjob.)
That said, the ORTF configuration of two cardiods does a great
job of capturing a full "scene" in the "front" of your position.
I've been really pleased with the naturalness and continuity of
imaging with this approach. Essentially, ORTF is the French
standard, and positions a pair of cardiods 17 cm (6.7 in) apart,
facing away from each other at 110 degrees. Not coincidentally
(pun intended), 17 cm is the average separation of human ears
(but ORTF has nothing to do with binaural recording).
Established in the 60's, ORTF stands for Office de
Radiodiffusion T=E9l=E9vision Fran=E7aise.
Important note on ORTF placement: Don't be a slave to specs.
Experiment with the separation and the angle, and you may find
that a specific set of mics in a specific environment sounds
best when it's not exactly ORTF.
I think of ORTF recording as a view onto a sound stage, whether
it's outdoors or inside. You get good attenuation of the
backside of the listening position (the audience, or the houses,
or whatever's behind you). The stereo image is good on speakers
AND on headphones, and mixes to mono quite well, which can be a
problem with other techniques.
Just for fun, the following link lets you compare some
orchestral recordings made with different micing configurations,
including Mid/Side (MS) which is cool, but a bit more tricky to
set up, and to monitor in the field:
http://tinyurl.com/rhyts
For more overview on mic configurations, take a look at:
http://www.wikirecording.org/Category:Microphone_Techniques
As for levels with the NT-1As on the 670, I may have been a
little misleading about "recording at 1." Ambient recording can
get VERY quiet, in which case 1 won't be high enough at all. But
strong winds, thunder, trees full of birds, etc., can be
surprisingly loud and often 1 is sufficient.
And yes, you can turn the gain down to zero! I've recorded
distant thunderstorms at 1.5, Celtic harps at 2, close vocals at
Message: 0.
Subject: 75, and ambience at 3 or 4. It's just nice to know you're
never cranking up the preamp noise very much (on a scale of 10).
And no, you don't need to attenuate the input stage, other than
adjusting the gain. But you do need to pay attention to overall
dynamic range, since the recorder itself, or the eventual CD, or
the mics, all have their own limitations. If you want a nearby
clap of thunder AND a faint faroff katydid, you may have to
settle for a VERY faint katydid and some deft gain-riding in
post. The 670 does provide a soft knee setting if you want to
protect against very occasional high levels.
Let me repeat my advisory about using large diaphragms
outdoors -- be very mindful of wind and water. Wind can "flap"
the diaphragm, producing huge low frequency voltage swings that
approach DC. You'll hear horrible subsonics and even huge thunks
and pops, and this stuff is hard to remove with low shelf EQ.
Seemingly still air can wuffle those gossamer membranes and ruin
a good recording.
Furthermore, water is bad for the membrane -- spit or dew or
raindrops can all (temporarily, we hope) mess with the flatness
and compliance of the diaphragm. Protect the NT-1As (or any
large diaphragm) from direct contact with water. Let them
temperature stabilize for an hour, if possible, when moving to a
much colder recording environment.
That said, I've never actually experienced any detectable
moisture problems with my NT-1As, even when recording under a
shelter in a rainstorm.
Oh, and "roomtone" is a film term for the environmental silence
of a particular location shot. One uses lots of roomtone in
audio post production for film and video, because (of course)
it's NOT silent at all.
ac
Allen Cobb
http://timbreproductions.com
-----Original Message-----
From:
Behalf Of Graham
Evans
Sent: Thursday, May 18, 2006 10:26 AM
To:
Subject: [Nature Recordists] pmd670 and roede NT1A's or AT3202's
(from the thread //Re: technology choices for gathering ambient
nature
noise/)/
> Hopefully the 670 will also cope, using these mics, with
recording
> sound at a slightly higher level than 'ambient' ie. spoken
word in a
> studio situation. If you are using the gain set at one Rob,
it can
> still go down to zero right. I have heard that, beyond that,
the
> internal 'pads' on the Marantz devices are very noisy.
>
> I will keep at my homework.
>
> thanks again
> Graham
er... I mixed up Rob's name with Allen there. Sorry... got it
now. The
question I was asking Allen is: if you have used the gain set at
one
while recording ambient noise then, using those same mics in a
louder
studio situation, will I need to pad the mic signal so it is
within the
input capacity of the pre-amp? From one to zero doesn't seem
like much
room.
The gear I am talking about here is the mazantx pmd670 (stock)
with two
roede NT1A's. If anyone has used those mics, or the AT-3032's,
along
with the pmd670 I would appreciate knowing whether they clip the
pre-amp
or require the pad to be turned on when recording higher volume
noises.
I am not talking about recording heavy-metal band type volume
but
spoken-word/ interview in a studio situation. Experiences with
the
pmd660 are also interesting to me.
I realise I may be trying to acheive too much with too little
kit here
and will keep thinking about other options like the HiMD's
suggested by
Rob, and possibly the cheaper solid-state recorders which would
allow me
to buy extra mics.
Graham
|