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## Re: Making a parabola

 Subject: Re: Making a parabola "freitojos" freitojos Fri Sep 21, 2012 7:28 am ((PDT))
 ```David, Once more thank you for your knowdlge and tips, they are precious. About your previous ( in another post) coment and answer about the stereo s= ound in a parabola, as you have said it is questionable but here are two fi= les with mkh 30/40 in a 60cm fiberglass parabola 15cm focal lenght, once yo= u have said, and it was right of corse, that the side gain was too low mayb= e it was the case here I d'ont remember, now I balance the gain in the two = channels better. http://soundcloud.com/freitojos/120627t0600z-santmargdaserra http://soundcloud.com/freitojos/122305t0600z-owls-cucoe In my cans and in my speakers I think it is stereo. My next experiment would be to put the mkh30/40 in my fiberglass 40 cm para= bola and compare the results with those in the 60 cm parabola. Regards, Jos=E9 --- In m("yahoogroups.com,","naturerecordists"); "Avocet" wrote: > > > This formula is a general formula for waves, light, radio or sound > > in a parabola, > > Jos=E9, > > This is exactly the problem. Sound waves are fundamentally different > from light and radio waves. Firstly, they are longitudinal not lateral > waves and secondly, their wavelength is comparable to the dimensions > of the parabola. Thirdly we are using them over a 20:1 range of > frequencies, not a narrow band like light or radio waves. The good > news is that the coefficient of reflection of sound with a solid > surface is near 100%. > > The bad news is that you won't get a clear focussed image from the > dish. The best you can hope for is the sound equivalent of a fuzzy > blob where most of the focussed energy will completely miss the mic. > That's the simplest explanation for the loss of low frequencies where > the blob gets larger. You can plot the focus pattern by moving around > a small mic. > > A parabolic mic does its job well, which is bringing in kilohertz > frequencies where it it more directional than any other type of mic. > Just don't expect a good music balance from one. :-) > > A general rule with location sound recording is to use what works in > practice. In the end our ears are the best judge rather than the > theory. > > David > > David Brinicombe > North Devon, UK > Cogito cogito ergo cogito sum - Ambrose Bierce > ```
 Current Thread Re: Making a parabola, (continued) Re: Making a parabola, Avocet Re: Making a parabola, Klas Strandberg Re: Making a parabola, MARTIN Re: Making a parabola, michael trommer Re: Making a parabola, Klas Strandberg Re: Making a parabola, Avocet Re: Making a parabola, michael trommer Re: Making a parabola, freitojos Re: Making a parabola, Klas Strandberg Re: Making a parabola, Avocet Re: Making a parabola, freitojos <= Re: Making a parabola, Scott Fraser Re: Making a parabola, Klas Strandberg Re: Making a parabola, Scott Fraser Re: Making a parabola, Klas Strandberg Re: Making a parabola, vickipowys Re: Making a parabola, Klas Strandberg Re: Making a parabola, vickipowys Re: Making a parabola, Serge Le Huitouze