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3. Re: Introduction

Subject: 3. Re: Introduction
From: "Rob Danielson" danielson_audio
Date: Sun Oct 26, 2008 12:20 am ((PDT))
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 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 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 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


>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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