Rob,
I like your description for a rain cover. I recently discovered a
material that I think will work very well for the hog hair part -
floor buffing pads.
I noticed them in the rental section of a hardware store. The ones
there are 1" thick non-woven plastic mesh and come in a couple
different diameters, 13" and the larger I'm guessing around 18". They
come in several colors that correspond to abrasiveness. Some were very
abrasive to touch, but the tan colored one I bought is soft enough to
be useful. They have a center hole, but the ones I found come with the
hole piece still in place - just needs to be glued in.
I got the 13" but now I'm thinking the larger one will be better for
cutting to form a hemisphere like you describe. My initial test of
holding it under the shower sounded very promising.
I'll report back with results once this project is completed.
John Hartog
--- In Rob Danielson <> wrote:
>
> At 12:52 PM +0000 11/7/08, colinbox wrote:
> >From the information and suggestions you gave, Rob, I have sketched a
> >rough design idea and recently showed it to my dad when visiting him -
> >he worked in mechanical and civil engineering all his life. We both
> >ran into difficulty regarding the "hogshair furnace filter" material -
> >this term does not appear to have a direct translation into UK
> >English! However, my dad suggested deer hide - with hair - as a
> >possible combined waterproof and rain-noise-suppressing 'roof'. He
> >also suggested sheep's wool as a possible material for absorbing the
> >sound of rain drops. Both these materials are freely available to me
> >(my brother is a deer stalker), but are these materials suitable?
>
> Hi Col,
>
> I suspect you are correct that the fine-woven, plastic material we
> call "hog's hair" is probably called something else in the UK. Its
> been around and used in furnace filters for many years-- most often
> in larger furnaces where larger, custom size filters are needed. Did
> you ask in a furnace supply company that specializes in industrial
> and new applications? The purpose of the hog's hair is to break-up
> the rain drops into a fine spray that are much less audible than drop
> impacts.. You can try a layer of 1"-2" thick fiberglass. The water
> runs through the hogs hair so whatever material you use should go on
> top of waterproof nylon like is used in umbrellas and tents. If the
> hemispherical cover is covered with nearly transparent materials and
> is large (around 2 feet in diameter), the lower rim of the cover can
> come down to the height of the mic capsules. It will take a very
> strong wind to blow rain into the capsules in this arrangement.
>
> Here's the design theory of the cover: The sound-transparent cover is
> to keep the rain and dew from falling directly on the mic wind screen
> where it can saturate the fake fur and drip onto the mic. The
> collection of dampness and water from blowing rain on the sides of
> the wind protectors needs to be able to drip off without puddling
> near the cables or mic bodies.
>
> Deer hide and Sheep's wool will not be transparent to sound. The both
> will also retain too much water and become too heavy.
>
> >With deer-hide for wind- and water-proofing I envisage making a
> >rectangular box with basic wood frame, hardwood "floor" (with standard
> >3/8inch fixing for screwing shock-mounts onto), nylon covering the
> >roof and 3 or all 4 of the vertical faces, and deer-hide (or other
> >suitable material) attached to the outside of a larger frame which
> >could be lifted off during dry weather... Does this sound like a
> >viable design concept?
>
> I wouldn't use _any_ kind of enclosure or box around or near the
> mics. Its likely to add resonance and interfere with mic array and
> sound performance. What type of stereo array are you using-- the NT3?
>
> > The hairy deer-hide would cover the top, rear, and 2 sides to
> >minimize noise from the house,
> >heating system, neighbours, etc, while leaving the front unobstructed.
>
> So you are not able to move the mics very far away from these less
> desirable sounds then? Increasing the distance from them is much more
> effective because most of the sound will wrap around any object you
> can construct-- especially low frequencies. A large tree or other
> surface that is not highly sound-reflective can provide some
> abatement of the mid and high frequencies.
>
> I wanted to experiment with 2- 4' X 8' X 1" MDF (medium density
> fiberboard) panels, water-proofed and covered with 1/2" thick high
> density foam in a slight "V" shape placed behind my parallel boundary
> stereo array about 4-6' to see if this would significantly abate
> sounds coming from the rear with my omni mics.
>
>
> >
> >Something I have discovered recently is that both my Rode NT3 and NT4
> >mic's do not exhibit the same "sputtering" noise when connected to my
> >external soundcard with balanced XLR connections and 48Volt phantom
> >power... So, instead of new mic's, I need a new recorder! The Edirol
> >R09 has served its purpose by igniting my passion for nature
> >recording, but now I need a 'proper' recorder!
>
> The R09 should be a pretty good fit for your NT-4 in terms of
> quality. I' not sure why the NT-4 would sputter if powered with 9
> volts,.. but if it does, and the NT-4 is the mic you want to use in
> the field, you could power it with an Art Phantom II between the R09
> and NT-4.
>
> If you are after lower noise performance than that you get with your
> NT-4 [~16 dB(A)], I'd study lower noise mics and array options first
> before buying any recorder. Buying the recorder before looking at
> your whole system is a common mistake. Rob D.
>
>
> >Has anyone got a decent
> >4-track field recorder (SD card or hard drive) they no longer use and
> >want to find a good home for?
> >
> >Colin
> >
> >--- In
>
><naturerecordists%40yahoogroups.com>
> >Rob Danielson <type@> wrote:
> >>
> >> At 10:21 PM +0100 10/25/08, Colin Brown wrote:
> >> >Thank you, nature recordists, for all the welcoming words of
support,
> >> >suggestions, and links. Martyn, you and your wife have my sincere
> >sympathy.
> >> >I'm blessed with wonderful family and friends and a great doctor
> >here in the
> >> >Lakes, so moving to a warmer, drier place is currently a more
painful
> >> >prospect!
> >> >
> >> >I live on the side of a hill with lush green fields stretching up
> >from my
> >> >garden fence to the horizon, so the idea of a microphone
outside in an
> >> >all-weather housing is very attractive. My garden is terraced and
> >no more
> >> >than 20feet from the house wall to the boundary fence. Roughly 50
> >feet from
> >> >the house wall are several thorn bushes, currently laden with
> >berries which
> >> >attract many bird species. As well as the common Blackbirds, Crows,
> >> >Sparrows, Robin, Chaffinch, Blue tits and Great tits, a stone chat
> >visits
> >> >these bushes, usually in the early morning, but I have yet to
> >record it. A
> >> >mic outside would massively increase my chances of recording its
> >surreal
> >> >calls. Bats also swoop around the back of my house all night but
> >recording
> >> >them will have to wait until I have enough experience and
appropriate
> >> >equipment! All this activity comes from within an angle of
> >approximately
> >> >90-120 degrees, depending how close or distant the listening
> >position is to
> >> >the rear wall of the house. By far the most abundant source of
> >berries and
> >> >birdsong is a single, centrally positioned bush, again roughly 50
> >feet from
> >> >the rear wall of the house and 30feet from the garden fence.
> >Unfortunately
> >> >the bathroom, kitchen, and heating system are all located at the
> >rear of the
> >> >house. I can still safely use carpentry tools (on good days!) so an
> >> >all-weather microphone housing will be my next project. If
anyone has
> >> >experience of building such a unit I would greatly appreciate
advice on
> >> >design and materials.
> >>
> >> Mic/array factors aside, a high priority goal of the rig design
is to
> >> eliminate rain and dew from striking or descending on the mic
bodies.
> >> A nylon umbrella will shed both or you can make a cage out of
> >> hardware cloth that even extends all the way down the sides.
Nylon is
> >> fairly sound transparent. You can also layer ~1"+ thick "hogshair"
> >> furnace filter material on top of the nylon which shatters rain
drops
> >> into fine spray make rainfall less obtrusive.
> >> <http://tinyurl.com/58xyyu>http://tinyurl.com/58xyyu A waterproof
> >>""roof" seems to greatly
> >> reduce moisture-related problems-- even those stemming from high
> >> humidity.
> >>
> >> The NT4, like most mics, is quite prone to handling noise which is
> >> usually addressed with some sort of shock mount. I cut out sections
> >> of 4" thinwall PVC pipe to create suspension rings.
> >> <http://tinyurl.com/5hzsfq>http://tinyurl.com/5hzsfq People use
> >>common rubber bands and silicone
> >> "O" rings to suspend the mics.
> >>
> >> Regarding wind protection, I sew a surround out of thinly woven,
long
> >> pile, fake fur. The fur should be no less than 1" from the capsules
> >> and fully enclose the capsules (if not the whole mic body).
> >> <http://tinyurl.com/6gucb2>http://tinyurl.com/6gucb2 The wind
> >>protection should be inside of the
> >> umbrella or nylon-covered cage.
> > >
> >> Regarding Mic positioning. In addition to attending to direction,
> >> avoid placing the mics near the ground or other large reflective
> >> surfaces. Many recordists feel that getting the mics ar least 7' off
> >> the ground improves clarity. Positioning the mic with the unwanted
> >> background sound coming from the rear and with a massive object in
> >> between can help abate the sound-- even a large tree trunk. Lots
more
> >> can be offered about mic positioning as you proceed.
> >>
> >> >There are 4 of us in my household so noise pollution
> >> >will be a major issue. Suggestions on minimizing this
> >noise-pollution would
> >> >also be great
> >>
> >> Its true that human and machine-made sounds from your house or
> >> neighbors tend to become annoying over time. Could you run mic cable
> >> further away from these sound sources? I use standard, balanced,
> >> studio-grade mic cable and encounter negligible signal loss at a run
> >> of 700 feet. I loosely suspended the signal-carrying cables from a
> >> taught electric fence wire stretched between trees with bungy cords
> >> at both ends to absorb tree movement.
> >><http://tinyurl.com/6cukav>http://tinyurl.com/6cukav
> >>
> >>
> >> >When the weather is dry my Rode NT3 and NT4 microphones re great.
> >However,
> >> >this being the Lake District, most days the atmosphere is damp
> >enough to
> >> >cause sputtering (often more than once a minute) which far
exceeds the
> >> >clipping level of my Edirol R-09 recorder. That's why the Rode NTG3
> >with its
> >> >advertised high-humidity capability looks so appealing, 5dBA less
> >self-noise
> >> >would be an added bonus.
> >> >
> >> >Before taking either the NT3 or NT4 outside and connecting to my
> >computer's
> >> >soundcard (PreSonus Firebox) does anyone know whether the
> >sputtering and
> >> >associated clipping would harm either my soundcard or PC - or
> >whether the
> >> >humidity would damage mic's?
> >>
> >> The literature on the Firebox specifies 20dB of gain on the mic
pres.
> >> This spec might be misleading, but the unit might also have less
> >> gain than is ideal, especially for ambience and night recording.
> >> You'll just have to test it and see. The noise spec for the unit is
> >> good. Don't be afraid to use full gain. The NT4 is not particularly
> >> sensitive. It will work better on phantom power, not batteries.
> >>
> >> I suppose a first step might be to get your NT-4 up and running.
> >> After you've done some recording, you can post some comments and
> >> sample recordings and folks will be happy to provide some feedback.
> >> Rob D.
> >>
> >>
> >> >
> >> >Thanks again,
> >> >
> >> >Col
> >> >
> >>
> >>
> > > --
> >>
>
>
> --
>
>
>
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