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Re: Boundary Size Test - was Wind in the Willow(s)..............

Subject: Re: Boundary Size Test - was Wind in the Willow(s)..............
From: "Peter Shute" pshute2
Date: Sun Apr 22, 2012 11:45 am ((PDT))
Same here. It's not listed at https://picasaweb.google.com/G0SBW.PM, so may=
be it's not available to the public?=0D
=0D
Peter Shute=0D
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Sent using BlackBerry=0D
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________________________________=0D
From: =0D
To: =0D
Sent: Mon Apr 23 04:02:36 2012=0D
Subject: [Nature Recordists] Re: Boundary Size Test - was Wind in the Willo=
w(s)..............=0D
=0D
=0D
=0D
Tom, I am following your experiments with much interest, but your last two =
posts have contained Picasaweb links which give me problems (like the one b=
elow) - they say simply "Sorry, that page was not found." Is it just me bei=
ng daft ?=0D
=0D
Chris=0D
=0D
--- In <naturerecordists%40yahoogrou=
ps.com>, "tk7859" <> wrote:=0D
>=0D
>=0D
>=0D
> --- In <naturerecordists%40yahoogr=
oups.com>, "tk7859" <g0sbw@> wrote:=0D
>=0D
> > I had completely overlooked that the MX391 is, in fact, a Wl183 already=
 mounted on a very small boundary and does therefore might have some bounda=
ry effect benefit as is. I wonder by what amount the effect is increased by=
 increasing the size of the boundary - to 5 1/2 inches square in my case?=
=0D
> >=0D
> > This thought raise a second question. Will my EM172 capsules perform in=
 a similar way to the MX391s if I reduce the size of their boundary to say,=
 a 3 inch diameter disc. My limited knowledge suggests they will, but I do =
not have the skill or equipment to test this.=0D
>=0D
> Hi All=0D
>=0D
> On the other hand I could just build one and give it a try.=0D
>=0D
> So I did that.=0D
>=0D
> I planned to use 3 inch plywood discs because they would make a good fit,=
 supported by rubber bands, inside the modified poly pipes mentioned in my =
previous post. However, I came across a couple of 3 inch diameter plastic t=
ops from Cringle crisp/chip tubes. The EM172s were easily fitted onto these=
 and suspended at the ends of the poly pipe. The sixth, seventh, eighth, ni=
nth and tenth photos, in the "two into one blimp" album start with the new =
rig fully clothed and follow its undressing thereby demonstrating how it wa=
s put together. The album is here:=0D
>=0D
> https://picasaweb.google.com/G0SBW.PM/TwoIntoOneBlimp=0D
>=0D
> The next job was to test it against a well performing largish boundary ar=
rangement. I chose the lightweight Shure MX391 equipped boundary (which per=
formed OK in comparison with a similar AT3032 equipped boundary. Photos 11 =
and 12 in the above album show the rigs as tested.=0D
>=0D
> The weather forecast for early this morning was reasonable; so 4 am found=
 me setting up the test in my back garden. The weather was not perfect as t=
here was a 10/12 mph wind with gusts. Because both the rigs under test were=
 PIP powered I used a HiMD minidisc for the MX391s and the LS-10 for the sm=
all barrier EM172s. Both recorders operating 44.1/16=0D
>=0D
> Recording started at 4:30, while still dark, and continued for just over =
an hour. Because of the darkness, and lack of a flash light, recording leve=
ls were set with more luck than judgement. As it happens, the recording lev=
el was fairly evenly matched on both recorders (the settings were "15" on t=
he HiMD and "high 4" on the LS-10). Other than picking a suitable snippet, =
adding fade-ins and fade outs and then converting to 320 MP3 the recordings=
 are as taken. There is a little wind rumble in places but, thankfully, no =
aircraft noise - there are few flights at this time in the morning. The com=
parison recording is below with the MX391 recording being the first 4 minut=
es followed by the same 4 minutes as recorded by the EM172=0D
>=0D
> http://soundcloud.com/g0sbw/new-blimp-test-mx391-vs-em172=0D
>=0D
> The recordings are not vastly different. To my ear the EM172 small bounda=
ry rig sounds a little more detailed and smooth? The last two photos in the=
 Picassa album above show the spectrogram and the waveform for the .WAV fil=
e.=0D
>=0D
> Prolonged listening might throw up more differences, but for now the new =
smaller boundary rig gets my vote. It is also some 3 to 4 ounces lighter th=
an a similarly set up EM172 larger, square boundary, rig. It currently is m=
y chosen handheld rig for the nightingale walk. Apparently the smaller boun=
dary size makes little difference?=0D
>=0D
> Any comment, critical or otherwise, is welcome=0D
>=0D
> Cheers, TomR=0D
>=0D
=0D
=0D
=0D









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