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Re: Ergonomic Barriers

Subject: Re: Ergonomic Barriers
From: "umashankar" umashanks
Date: Tue Jan 30, 2007 5:59 am ((PST))
i had been building arrays of small capsules for atleast 20 years now. i ta=
ke a plate of about 6 inches square (it can be smaller) and mount five caps=
ules in a kind of irregular cross. there is a central capsule, one capsule =
is half inch away, the next one, at right angles, about an inch, the third =
an inch and half and the last two inches. i parallel all the capsules and t=
reat them like one. it not only improves the noise figure (by about 12 db i=
 think) it makes it surprisingly directional. there is cancellation of soun=
d from any angle other than 90 degrees to the plate (the irregular arrangem=
ent is to meld all the cancellations) and mounting them on a plate gives yo=
u a very clean boundary layer effect. there is no pick up at the back, whic=
h also doubles your figure of merit.

umashankar

(we will build one in the forests of karnataka next week)

umashankar




----- Original Message ----
From: Rich Peet <>
To: 
Sent: Tuesday, January 30, 2007 11:10:52 AM
Subject: [Nature Recordists] Re: Ergonomic Barriers


Yes the capsules have to be right next to each other in order to
increase gain.
So we are talking about the same thing it takes 6 capsules total to
make both channels. Verticle triplets are to minimize phase differnce
and maximize gain as the majority of sound in natural sound recording
is in a horizontal plane.

I did build a tight triangle configuration and it worked just fine.
That was a variation of the "Two-Sided Boundary Mic" as seen on Robs
page,
http://www.uwm.edu/~type/audio-reports/PanasonicWM-61A_OtherBinauralRigs/WM=
Message: 61A_Webpage_Caps_Mounts.
Subject: html
Further, Klas has extensive experience using 4 capsules per channel as
a tight rectangle and that works fine.

I have not yet played with spacing the capsules in different patterns
to make directional arrays and that is a science all on its own.
There has been a thread or two from people playing in that area here.

Rich

--- In  Lou Judson <> wrote:
>
> Rich, I don't keep careful enough track of what is from whom here, so
> sorry I don't have the image link to hand... Have you tried putting the
> three capsules right next to each other (vertically, not left and right
> channel) instead of having space between them? Would they still add up
> the same way? What if they were in a tight triangle? I'd think the
> phase similarity would increase the gain... but that's just a thought.
> Have you experiemented?
>
> <L>
>
> Lou Judson =95 Intuitive Audio
> 415-883-2689
>
> On Jan 29, 2007, at 5:35 PM, Rich Peet wrote:
>
> > hard to stop a mind, sort of like standing in front of a train.
> >
> > I built the triplet as a noise reduction technique to bring a low
> > noise result using cheap higher noise mics.  By putting them in align
> > verticle you get the same time of arrival.  Any space apart of the
> > mics causes problem starting at high pitches and working down.
>




"Microphones are not ears,
Loudspeakers are not birds,
A listening room is not nature."
Klas Strandberg
Yahoo! Groups Links





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