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## 5. Re: parabolic mics

 Subject: 5. Re: parabolic mics "Jose Freitas" =
 ```cketmail.com Date: Thu Jun 16, 2011 5:48 am ((PDT)) Hello, I have used this exel http://graffiti.virgin.net/ljmayes.mal/var/parabola.htm after computation you make your elements in hard papel, you connect the ele= ments toghether with tesa film you chose a place with sand and you put the = paper parabola sustained by the sand. After that you make with water and cl= ay a soup, you put the soup in the parabola for one day. With a knife and s= and paper you makes a good mold. After that you puts the fiber glass, two t= imes at least but you can make the parabola as thik as you like it. Good job, Best regards, Jos=E9 --- In m("yahoogroups.com,","naturerecordists"); Peter Shute wrote: > > You made your own dish? Can you share construction details? How did you d= esign and make the mould? How thick did you make the dish? > > Peter Shute > > > -------------------------- > Sent using BlackBerry > > ________________________________ > From: m("yahoogroups.com","naturerecordists"); > To: m("yahoogroups.com","naturerecordists"); > Sent: Thu Jun 16 21:45:30 2011 > Subject: Re: [Nature Recordists] parabolic mics > > > > Hello, > I hope this will help > http://soundcloud.com/freitojos/ms-stereo-the-first-3-5 > > I put ms mkh 30/40 in a fiber glass 65cm parabola that I made and the foc= us of the parabola was the line in the limit of the parabola not inside the= parabola, in the limit. > Best regards, > Jos=C3=A9 > --- In m("yahoogroups.com","naturerecordists");, "diesel33dsl" wrote: > > > > Thanks all dudes! > > > > Most of your answers can be synthesized with a 'try it and see' basis. > > Thats what I'll be doing then, once I have gear and mikes enough to mak= e comparisons (and software and measurement tools too, we could give some w= ords here also about what tools you use). > > > > It is a pleasure to read your debates and opinions, specially now I am = starting to take it seriously. > > > > About using parabolas, i guess my decision is to gather some coins and = try to ask one of those swedish to send me a telinga set :) > > > > Positioning a shotgun mic in a parabola seems quite an unexpected go si= nce I'd be combining two different caption ideas (thanks David B.) and prob= ably locating the capsule in the focus is not easy due to mike size and so = on... I guess the same happens when trying to locate there two isolated mic= s for a stereo take of a distant element. > > > > Thanks Raimund also, your Goshawk take makes worth the try with my appr= oach. > > > > What's clear is that small/light mikes will fit best there and omnis po= inting to reflected sound are best choice... > > i guess the Telinga sets include good mikes on them, specially designed= for better performance, but has anyone of you got better results by swappi= ng default Telinga mikes with others? > > Or, is my choice to get a Telinga set (dish, handle, mount) without mik= es and put some specific models there? > > Which models/brands go well here? > > > > Thanks! > > > > --- In m("yahoogroups.com","naturerecordists");, "Avocet" wrote: > > > > > > > Question 2: > > > Is the parabola approach designed to be used with JUST omni mics? > > > Are other caption patterns allowed, or is it senseless to use > > > directional mics here? > > > > > > Dani, > > > > > > As a supplementary answer, try any mic with a parabola and see what i= t > > > does. However, bear in mind that a double mic or a gunmic will be > > > wider or longer than the high frequency focus of the parabola so the > > > basic parabola theory won't apply. > > > > > > > Does this enhance directivity for a shotgun? > > > > > > You would be combining two very different directional principles and > > > it is unlikely that they would reinforce each other's characteristics > > > but try it. And it is likely that they would reinforce each other's > > > disadvantages. > > > > > > BTW I regard the MKH 416 one of the most useful mics available and > > > can't see how it can be improved on except for the MKH 816 (still > > > available second hand). If you have a bottomless pocket there is the > > > MKH 8070 which has an amazing spec but I can't afford two of them for > > > stereo. :-) I think the law of diminishing returns would act here, > > > money-wise. > > > > > > Going to basic parabola theory: > > > > > > a) The focus is finer at higher frequencies and virtually non-existan= t > > > at low freqencies. > > > > > > b) An omni mic will pick up both direct sound and reflected sound and > > > at some frequenies these will tend to cancel out, but for most wanted > > > frequencies the reflected sound swamps the direct. > > > > > > c) A cardioid theoretically avoids cancellation effect type b) but > > > other diffraction effects still apply. A cardioid is always more > > > susceptible to wind and handling noise. Take your pick on > > > disadvantages. > > > > > > d) Stereo with a parabola is only possible using two points just > > > off-focus on either side. The theory behind this is complex so trial > > > and error is the best method of finding out what works. > > > > > > David > > > > > > David Brinicombe > > > North Devon, UK > > > Cogito cogito ergo cogito sum - Ambrose Bierce > > > > > > > > > > > ```
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