Hi Rob,
Actually I have no idea when Jecklin updated his OSS scheme, I misinterpret=
ed the description on the Josepheson web site(http://www.josephson.com/tn5.=
html) where it mentions 2009, and I now see it does not directly refer to t=
he date of publication. The paper referred to is dated in the footer as 200=
3/04.
Anyway, it would be interesting to experiment with that spacing variable so=
metime. In my own baffled arrays I have kept distance between mics more or =
less head-spaced. Having them closer to the baffle is certainly more conve=
nient for wind screening and for portability, but if wider spacing proved t=
o be noticeably superior in a variety of situations, then I might be inclin=
ed to adopt that configuration.
Of course there are many variables worth exploring as you have pointed out.=
I have strayed away from the smooth, flat, and perfectly circular charac=
teristics of the Jecklin design. There is some crazy idea in my head that =
if the baffle must be reflective to some degree, and if those reflections c=
an cause phase issues, then the baffle should at least be shaped to scatter=
those reflections as much as possible. I don't really know what differen=
ce if any that makes, but I do it anyway.
Getting back to the SASS-like boundary arrays you have been testing. I thin=
k there is a lot to learn from your latest comparison (http://diystereoboun=
darymics.blogspot.com/). I like the squirrel, however I am afraid that the=
same as with the old clock tick tock, it might still cause insanity if lis=
tened to one too many times. One thing I find interesting is how off-axis =
coloring of the 90 degree source in the flat or angled-in configurations gi=
ve the illusion (headphones) of a source slightly from the rear =96 that ma=
y or may not be desirable depending on the circumstance.
John Hartog
--- In Rob Danielson <> wrote:
>
> Hi John--
> I didn't realize the separation distance change was recent. It would
> be fun to experiment with some of the variables. Good diffuse field
> Hz response appears to be one of the strengths Jecklin points to
> which is very relevant to our applications. One would need to dive
> into the papers of course, most of them in German, but here are few
> traits that stand out to me:
>
> Perhaps the 13 - 3/4" diameter dish prevents sound waves higher in
> frequency (shorter) than ~1000 Hz from passing around the dish (speed
> of sound =3D 13600 inches per second / 13.75 inches =3D 989 Hz). As Eric=
> Benjamin reminds often reminds us, our brains can use time of arrival
> differences only up to 1000-1100Hz-- so it seems the "off-side"
> timing differences would NOT be blocked while the off-side
> frequencies above 1000 Hz would be.
>
> One can imagine "shadowing" or diffraction around the dish creates a
> potential of directional cues. The shadow formed by a sound wave
> would be different depending on angle of incidence and frequency.
> Unlike our ears, the spread between the mics affects how far into the
> "shadows" the mics extend.
>
> Simply adding some padding to hard surface doe not eliminate
> reflections. On-side lower frequency sounds coming from the right and
> left (between ~1:30 to 4:30 and 8:30 to 10:30 o'clock) will reflect
> back to the mics from the baffle creating potential phase relations.
> From my own attempts at blocking sound from the rear for surround mic
> arrays, I found that I had to place heavily treated barriers at least
> 2 feet away or I'd hear the affect on the mics frequency response.
> The closed-cell, rubbery boundary and baffle materials that some
> people are experimenting with can change coloration as well.
>
> As far as I can tell, very little of the designing, testing and
> theorizing audio engineers do takes into consideration "diffusion" to
> the extent that we engage it when recording ambience in "quiet," very
> large, non-geometric spaces. We've been doing this almost long
> enough so that we can start looking for ties between arrays that do
> things we like. For example, the SASS uses a partial baffle. Rob D.
>
>
> =3D =3D =3D
>
>
>
>
> At 9:09 PM +0000 9/26/10, hartogj wrote:
> >Hi Kevin,
> >
> >Baffled arrays, including the Jecklin disk, are definitely
> >appropriate for nature recording. I have found that a baffle can
> >establish accurate left to right imaging independent of chosen angle
> >between axes or polar pattern of the microphone capsules. Such
> >flexibility allows for explorations of a variety of interesting
> >perspectives of the natural soundscape. The basic Jecklin disk
> >design is certainly elegant where function meets simplicity.
> >
> >I notice Jecklin recently published an update that more than doubles
> >the ideal spacing between capsules, the original was 16.5 cm, but
> >now it is 36 cm. That seems quite a big shift. It would be
> >interesting to hear the difference.
> >
> >John Hartog
> >
> >--- In
> ><naturerecordists%40yahoogroups.com>=
com,
> >Kevin Colver <colver@> wrote:
> >>
> >> Rob,
> >> I've made my own Jeklin disk with about $25 of materials (not
> >> including the microphones) and used it this summer. Your comments
> >> about the Jeklin were fairly positive. I'm wondering if others in the
> >> group have found the Jeklin useful for nature recording?
> >>
> >> Kevin J Colver
> >> Soundscapes for Birders - a Podcast of Natural Sounds
> >> www.7Loons.com
> >>
> >>
> > >
> >>
>
>
> --
>
>
>
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