A part fell out from my posting:
One must remember that microphone manufacturers might keep down their
output voltage on purpose, not to distort the input amp of a consumer MD,
if you record at a pop concert or blow the trumpet into the microphone.
Therefore, a consumer microphone may very well be very good, - for general=
purposes - but doesn't fit the naturesound recordist, as the output is too=
low to override the consumer MD input noise.
Klas.
At 17:41 2005-09-01, you wrote:
>Do you think we'll be able to get a sensitivity number or even an
>accurate range of mV/Pa : dbB(A) combinations that will apply to
>DAT/MD/HiMD mic preamp's in general? I tested the Rode NT-1A's with
>the Rolls phantom power supply with these recorders:
>
>NH900 HiMD
>Sharp MT-90
>Sony D-7
>Sony TRV-900 (video camcorder)
>
>and found that the NH-900 is significantly quieter than the other
>recorders with the Sharp MD being the noisiest.
That doesn't surprise me. Sharp got some stupid ideas from last years
models, the input PIP current regulator, for one.
From my perspective: Many customers use a "Walkman" type MD. Sharps, too.=
I want to provide a microphone which output is high enough to override the=
input noise of such a machine.
All Telinga mic's (without dish, of course) make about 14 db(A) noise. With=
the capsules I use, and the FET-IC's I use, this comes free. Without any
complicated circuitry, all Telingas override the input noise of even a last=
years Sharp. I know that, because I use the poor Sharp machines as "minimum=
reference".
But when people here are choosing other mic's, I think there would be at
least some reference, at least referring to the NH900.
That is: If you use a NH900 - then you can use any electret providing more=
than xx mV/Pa with a self noise lower than 14 db(A). If you do, you don't
have to worry about the NH900 input noise. The noise you get, is from the
electret.
Or vice versa: If you use a Sharp MT-90 - then a 14db(A) microphone must
provide at least yy mV/Pa to override the Sharp input noise.
Klas.
>I've been thinking about the min mV/Pa question since you posed it a
>while ago. I came across table #3 on
>http://www.rane.com/note148.html. With this chart, it seems like we
>might be able to take what we know about the NH900 performance to
>estimate the noise floor of NH900 mic pre for starters. I'm pretty
>confident that the noises I'm hearing when I hook up:
>NT1A->Rolls->NH-900 are close to a 50-50 blend of mic and NH900 mic
>preamps. Applying the NT1A's specs* to table #3, I get ~-118 dBu for
>the NH900 HiMD mic pre, but I'm blindly following the chart and other
>aspects of the chart confuse me. Rob D.
>*6dB(A); 25mV/Pa
>
> =3D =3D =3D =3D =3D
>
>At 11:34 AM +0200 9/1/05, Klas Strandberg wrote:
> >With only 5,6 mV / Pa I am certain that you get MD preamp noise.
> >You need too much gain.
> >
> >That is what I would like to discover: At which output / Pa does a typic=
al
> >MD preamp noise "take over".
> >
> >Klas.
> >
> >At 04:44 2005-09-01, you wrote:
> >>At 5:07 PM -0700 8/31/05, Dan Dugan wrote:
> >> >Lou Judson wrote:
> >> >
> >> >>Curiosity took me to the Soundprofessionlas website this morning, a=
nd I
> >> >>see they have some closeouts on their stereo pairs already wired fo=
r
> >> >>PIP - $49 instead of 129. Has anyone compared theirs to such as the
> >> >>Shure 183s? Ths ones on sale now are cardioid, yet for some of what=
I
> >> >>do they would be ideal.
> >> >>
> >> >>http://www.soundprofessionals.com/cgi-bin/gold/item/SP-CMC-22
> >> >
> >> >It was Sound Professionals who turned me on to the 183s, just before
> >> >they changed to something else.
> >> >
> >> >Sharon Perry uses SP cardioids, which are Audio-Technicas, for her
> >> >vest. Gain is about the same as 183s, but the cables are quite
> >> >microphonic. Don't know if that's the type they're currently using.
> >> >
> >> >If the s/n of "58" is correct, 94-58 =3D 36dB, pretty high.
> >>
> >>and a (lower) sensitivity of 5.6mV/Pa (high mV/Pa #
> >>[sensitivity.output] is good; low dB(A) # [self noise] is good.)
> >>
> >>compare to:
> >>Panasonic WM61a capsule 32.5 dB(A)* 18 mV/Pa **
> >>spec sheet: http://tinyurl.com/8g4l9
> >>Cost $16.21 for 10 + shipppiing http://www.digikey.com/ and enter
> >>"wm-61a" into parts search.
> >>You can solder a workable set to run on MD/HiMD plug in power for a
> >>few bucks more http://webpages.charter.net/tidmarsh/binmic/
> >>
> >>*Based on Eric B's test on file on the micbuilders list.
> >>http://tinyurl.com/8tkt4 **Is this sensitivity number right? Eric's
> >>test seems to confirm Panasonic's figure of (0dB=3D1V/Pa, 1kHz)
> >>-35+/-4dB.
> >>I need to learn how to make this conversion.
> >>
> >>and for reference:
> >>ShureWL-183 22 dB(A) 29 mV/Pa
> > >Rob D.
> > >
> >
> >Telinga Microphones, Botarbo,
> >S-748 96 Tobo, Sweden.
> >Phone & fax int + 295 310 01
> >email:
> >
> >
>
>
>[Non-text portions of this message have been removed]
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
Telinga Microphones, Botarbo,
S-748 96 Tobo, Sweden.
Phone & fax int + 295 310 01
email:
=20
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