I second the advice given here. Tropical forests are extremely unpredictable
and the environment can seriously challenge the "best" equipment. Redundancy
really is your best friend. Extra memory, extra cables, extra microphones,
extra batteries, extra watertight bags. This is one of the most important notes
to self in my notebooks.
My own experience with a pair of Sennheiser mics showed that they lasted about
3 to 4 days before humidity set in, but even at that point they would "warm up"
depending upon how thick the air was.
For instance, an early evening recording session had them sputtering for an
hour, then quite clean for the duration of the night, only to begin sputtering
again in the morning. This field observation may support Rob's regarding the
practice of turning the mics on and leaving them on - or the need for a period
of acclimation. One thing that may have contributed to this situation was an
inability to control humidity when not recording... so perhaps here some
desiccant can help (i will certainly be taking desiccant with me in the future).
The causes of (and solutions to) humidity related noise in condenser mics, as
Rob has noted here in the past, are not completely understood - so I would be
interested to hear your techniques and results in the field.
David
> Optimistic thinking can bring out the worst in gear. :-) The adage,
> "I'll take a spare to be sure that I don't need it, " comes to mind.
>
> I like to power-up condenser mics, outside, 3-5 hours before I'll
> really need them and leave them on. If the
> popping/fizzing/sputtering/whining doesn't stop after 5-7 hours, then
> I seal the mics in a ziplock bag with several desiccant packets for
> 24 hours and start over.
>
> A few more precautions to toss in: Take more power and media than you
> think you'll need even on short excursions. Carry redundant memory
> cards, power and a pair of cheap ear buds in the case. Bring
> redundant cables, connectors, adapters for camp. Also in the
> recorder case, a plastic bag large enough to quickly cover the whole
> rig in a downpour*. For camp, an extra portable phantom supply to
> keep mics that are acting-up powered and hopefully "working-through"
> the moisture issues. Practice using any new set-ups before taking
> them out and go through all of the knobs and menu settings before
> hitting the trial. I'm more likely to do really, really stupid things
> when the recording conditions are exciting.
>
> *In addition to your rain cover set-up.
>
> re:
> >I'm mostly interested in stereo/binaural ambient recording. Link to
> >something I am fairly happy with so far, done locally in London, at
> >the end (ambient recording of rain, not critters).
>
> Thanks for posting the recording examples. If spaciousness is a
> quality you'd like to emphasize in your recordings, you might enjoy
> experimenting with spaced stereo arrays before heading off. The mic
> capsules in the coincident, X-Y and M-S arrays, as with your sample
> recordings, are placed close together, not ear-spaced as is typical
> of binaural types. In broad bandwidth settings and especially with
> dense sounds like rain, spaced arrays tend to produce less bunching
> of the sounds in the center of the field. Here's an archive search
> with some matches that will point you in directions that recordists
> have explored from arrays to mics used: http://tinyurl.com/yz27qol
> If you don't have a bunch of money to spend on omni mics that can be
> separated, the Shure WL183s are one, popular option. Maybe someone
> can help you find a local source for them. Enjoy your trip and let us
> know know it goes. Rob D.
>
> = = =
>
>
> At 7:38 AM -0800 3/7/10, Scott Fraser wrote:
> >
> ><<You will be amazed and in awe of the rainforest! Since you'll be
> >there for only a few days, the chances are you won't have any problems
> >with humidity. >>
> >
> >In my experience in rain forest climates the deleterious effects of
> >humidity upon externally polarized condenser mics was immediate & none
> >of those recordings were usable. Within a minute of powering up a pair
> >of C451's they were popping continuously.
> >
> >Scott Fraser
> >
>
>
> --
>
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