Thanks for the description of the process. I like the idea of
substituting a known mic as a reference to get an approximation if
one doesn't own test gear.
Pardon my persistence. Are you _not_ saying that 14dBA self noise
will serve as a reference for a mic used with NH900 mic pre,
regardless of mic sensitivity? If you _are_ saying this, I was
trying to understand how you applied what we know about the NH900 pre
to come up with the reference of 14dBA when making nature recordings
with low noise mics and HiMD recorders, that is. :-) Rob D.
=3D =3D =3D =3D =3D
> where the pre would produce more noise
>than the mic. After you deteremined that mic has 14dB(A) self
>noise, did you determine that from a audible test then after the
>mic is
At 3:16 PM +0200 9/4/05, Klas Strandberg wrote:
>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), The=
n
>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, yo=
u
>> 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 po=
wered
>> >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:
>
>
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
--
Rob Danielson
Film Department
University of Wisconsin-Milwaukee
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