So would I....
Klas
At 06:37 2010-07-26, you wrote:
>Umashankar, hi!
>
>I would very much like to read quantitative text about your experiences with
>these various capsules and the FET preamp circuits that you have
>developed over
>time. The array of mics on a flat surface is one application of
>beamforming that
>can produce a very directional mic, but I am curious if just paralleling some
>capsules would produce an optimum effect. But, please, fill us in on the
>details!
>
>I have just received some Primo 172s & 173s, so it is time for me to
>develop an
>mic array that will be low noise and very detailed in localization.
>
>Thanks for your interest and support!
>
>-Greg
>
>
>
>________________________________
>From: umashankar <>
>To:
>Sent: Wed, July 7, 2010 10:07:34 PM
>Subject: Re: [Nature Recordists] Re: plug-in power mic
>
>
>i have been building paralleled arrays of capsules since 1985, initially
>because the cheap capsules i could get in india were just too noisy
>to be used
>singly. i then figured that if i mounted them in an array on a sheet
>of plastic,
>
>even just ten cm square, i would get an extremely directional mic
>which i used
>for many documentary films.
>
>initially i powered them with a 9 volt battery and single 2k2 load resistor -
>shared by all the capsules. the sensitivity of individual capsules was lower
>than if the circuit powered a single capsule, but the overall
>sensitivity - with
>
>five capsules arranged in an irregular cross - was much higher.
>
>Later i tried a current source - fet with a source resistor, as load, and i
>observed sensitivity change quite dramatically as the battery
>voltage fell which
>
>was the opposite of what i expected. but i could run the battery down to
>nothing.
>
>these days i am running most of my microphones with the pip (2
>volts) available
>on the zoom h2, both with external fets (2sk 170) and built in ones. i am
>getting very high output with a 25 mm electret capsule, and lower
>outputs from
>12 mm and 14 mm capsules.
>
>there is an interesting design for upgrading a pip circuit so it gets to be
>really low impedance - useful for running long cables. i can dig it out if
>there is any intest. (it is there in the mic builders member's files)
>
>umashankar
>
>i have published my poems. you can read (or buy) at
>http://stores.lulu.com/umashankar
>
>________________________________
>From: Dan Dugan <>
>To:
>Sent: Thu, July 8, 2010 7:50:57 AM
>Subject: Re: [Nature Recordists] Re: plug-in power mic
>
> > So guys, you're saying that mic sensitivity will vary with PIP
> > voltage? Is this limited to the unnamed capsules Mike has tested, or
> > is this a general rule of thumb that will apply to other PIP mics
> > also, like WL-183s?
>
>I've been thinking that the sensitivity of PIP mics is constant with bias
>voltage but that the maximum SPL before distortion varies--which is
>why concert
>tapers use 9V supplies, but nature recordists don't have to worry at
>1V or even
>less.
>
>But I may be wrong. Or there's a difference between electret mics
>with FETs and
>those with ICs?
>
>Can the mic builders clarify this?
>
>-Dan
>
>------------------------------------
>
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>------------------------------------
>
>"While a picture is worth a thousand words, a
>sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
>Yahoo! Groups Links
>
>
>
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email:
website: www.telinga.com
"While a picture is worth a thousand words, a
sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
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