the rigid parabola scores only in one respect - efficiency. a straightwalle=
d cone will work, as will a spherical boundary. i have been interested in s=
hallow spherical surfaces because they reflect to a focus even if the sourc=
e is not normal to the surface - opening up possibilities in stereo recordi=
ng. (xy mic at the focus ?)
=A0
umashankar
=A0
>________________________________
> From: grummyaa <>
>To:
>Sent: Tuesday, September 18, 2012 8:36 AM
>Subject: [Nature Recordists] Re: Microphone advice for Parabolic please
>
>Yeah. I've seen a number of articles and at least one video on the DIY dol=
lar store umbrella hat reflector before. If I come across one of those sill=
y hats I will make one to try. I'm just skeptical of the audio quality of s=
omething like that. I read somewhere that I'd need a dish at least 18-19" i=
f I don't want to filter out anything below 500hz drastically. Does that so=
und accurate? In which case the little umbrella must cut off even higher up=
.
>
>Also if it's not a true parabolic does it not risk comb filtering at all. =
Or is the advantage of a true parabolic simply just a bit more "amplificati=
on"? Does a non parabolic potentially amplify more unevenly across the spec=
trum?
>
>
>Known that the Telinga offerings are much cheaper than the other options I=
listed is indeed very helpful. I would hope to be able to get a decent siz=
ed plastic parabolic dish for under a hundred bucks though. Especially cons=
idering what the material to make such a dish would cost. In the end wouldn=
't it just be a mold similar to how a plastic salad bowl would be made?
>
>I hope I'm not coming across as too ignorant of a cheap=A0 dick. I just do=
n't understand why it would cost $200 -$1000 for such a thing. I suppose so=
me R&D was involved but in the end aren't they just moulding plastic to spe=
c. Or are they using special material that normal hardened plastic cannot d=
o?
>
>
>--- In Jim Lee <> wrote:
>>
>> Just to reinforce the "secret' allow me to reintroduce that really
>> inexpensive and whimsical parabolic mic made from an umbrella hat. It
>> does remarkably well considering what it is made of. Some sample
>> recordings on the site:
>> http://www.bambooturtle.us/ParabolicMicrophone.html
>>
>> Jim
>> On 9/17/2012 6:56 PM, Avocet wrote:
>> >
>> > > So I'd like to know where you all are finding your suitable
>> > > parabolic reflectors? Or are you folks seriously dropping $1000 + on
>> > > something like a JonyShot, Lil' Ears, or Telinga and dropping $10
>> > > electret mics into them.
>> >
>> > I'll let you into a secret - you don't need an exact parabola. If you
>> > can find a cheap dome or a used skylight, experiment with that.
>> >
>> > The advantage of a custom made parabolic rig is that someone else has
>> > made it work and ones like the Telinga fold up and are light to carry.
>> > The original parabolic mics were made from ex-military radar dishes
>> > which were heavy and difficult to handle. Sound parabolas were also
>> > made on a mould out of fibreglass, but that is a messy job and they
>> > are also heavy and clumsy.
>> >
>> > I'm playing with my alternative Brinibox design which can be lighter
>> > and which gives a good stereo image with about 12dB boost so you can
>> > get results from cheap mics.
>> >
>> > See:
>> > www.stowford.org/sounds/brinibox.htm
>> >
>> > David
>> >
>> > David Brinicombe
>> > North Devon, UK
>> > Cogito cogito ergo cogito sum - Ambrose Bierce
>> >
>> >
>>
>> --
>> Jim Lee --- Bamboo Turtle Studio
>> Website: http://www.bambooturtle.us/
>> Blog: http://bambooturtle.blogspot.com/
>> Rock Nest Monster:http://www.bambooturtle.us/Rock_Nest_Monster.html
>>
>>
>>
>>
>
>
>
>
>------------------------------------
>
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
>
>Yahoo! Groups Links
>
>
>
>
>
>
|