You expose the microphone to a sound pressure of 94 db and set the
instrument to zero db. (Reference level) Then you switch off the 94 db and=
measure the remaining noise through a specified A-weighted filter built
into the voltmeter.
You can also connect a MKH20 and set the self noise level at 10 db(A), Then=
you compare with your own microphone.
Klas.
At 19:55 2005-09-03, you wrote:
>At 7:04 PM +0200 9/3/05, Klas Strandberg wrote:
><snip>
> >
> > > >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.
> > >
>
>Rob D asked:
>
> >Makes sense in theory. Can I ask you how you came up with 14dB(A)?
>
>Klas replied:
>
> >
> >I measured, just as one should. I have the Sennheiser meter with the
> >normalized filters.
>
>Rob D followed:
>
>What is it you measured? The self noise of a reference mic or,..??
>I'm still curious about how you arrived at that number. Just to be
>clear: This number would be the minimum self noise figure (actual,
>not just manuf specs, somtimes) for a mic used with an NH900 mic pre,
>regardless of mic sensitivity, where the pre would produce more noise
>than the mic. Right? Wrong?
>
>Rob D. asked
> >
> >>Are you addressing electret mics only in this
> >>summary? I mean, they have higher self noise as
> >>rule compared to condensers.
>
>Klas Replied:
>
> >No, not only electrets. But I think that the ones going for phantom powe=
red
> >condensor mics (usually) have other recorders than Walkman types.
>
>Rob D. followed:
>This may be less and less the case with people using a $70 portable
>phantom unit like the Rolls. That's how I found that the low noise
>performance of the NH900 was good, connecting the NT1A's through a
>Rolls.
>
>
>
>
>
>
>
>
>
>
>
>
>
>"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:
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