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Re: Re: recorder - mic pre factors

Subject: Re: Re: recorder - mic pre factors
From: Rob Danielson <>
Date: Thu, 28 Jul 2005 17:46:21 -0500
At 12:28 AM +0200 7/29/05, Klas Strandberg wrote:
>Rob, we should need that malt and a night's conversation before we agreed
>on the terminology and other stuff. Measuring methods, for example. I don'=
t
>think I understand what you mean and what you base your observations on.
>That doesn't mean that you are wrong.

How about,.. talking about the test,  "The noise contributions of
both pres and the mics are all on the same order-- so close to the
same as to not worry about it. "The mics have a self noise, (which
Eric confirmed in his tests)  very close to 6dBA."

>
>Finally, with help from your tests and Oryoki's summary, it seems that I
>have made my point in a way that can be understood. Thanks, all.
>
>It is strange how difficult it is to put a new microphone outside, to leav=
e
>it there, in rain and wind. I mean, - I bought the NT1- A only for that
>purpose, but every night when I am going to put it there, under the small
>rainshield, I seem to forget it.... It feels strange to do such a thing.

Try 6 mikes plus $6000 worth of recorders, in the woods, all night, 1
mile away during horrendous storms. Its happened to me twice this
summer alone. I've gotten better at roping stuff into the trees so it
moves with the wind/trees, not against it.  The best part is when a
critter waits out the storm under your umbrella.

My gosh, it is late. I should go have a cold one. Cheers! Rob D.

>Klas.
>
>At 22:37 2005-07-28, you wrote:
>>At 9:31 PM +0200 7/28/05, Klas Strandberg wrote:
>>  >At 20:47 2005-07-28, you wrote:
>>  >>Let me try to re-state Klas' message:
>>  >>
>>  >>1. Each mic has a self-noise level, produced by the components in its
>>  >>design.
>>  >>
>>  >>2. The recorder pre-amp cannot cancel or compensate for the mic
>>  >>self-noise level.  This mic noise level will always be part of the
>>  >>recording.
>>  >>
>>  >>3. The recorder pre-amp has a self-noise level of its own.  This nois=
e
>>  >>is also added to the recording.
>>  >>
>>  >>4. If the mic output signal is strong (i.e., has high mV/Pa), it can
>>  >>over-ride the noise of the recorder pre-amp.
>>
>>Yes! Excellent. A couple of nit pic  "real circumstances" extensions,..
>>
>>If the self noise of the mic is higher than the "effective self
>>noise" of the pre  (and most of the time this is true with or good
>>pre like the 722 or, as we found, even the lowly HIMD if properly
>>out-fitted and no longer compromised),  then, there is very little or
>>no noise from the pre to over-ride! That is-- the mic has already
>>buried it.
>>
>>The test I posted seems to indicate the noise from the HiMD pre is
>>right around the self noise of the mic, "effectively ~6dBA*."  Above
>>half of the noise I EQ'd out I could tell was from the mics because
>>it was different in each channel. I could also distinquish some very
>>narrow bands of noise that seemed to be a 722 contribution, not the
>>mics.
>>
>>    [* I say "effectively" because we're listening to/comparing the end
>>results and judging the difference not really measuring dBA's of self
>>noise in the pre]
>>
>>  >  >
>>  >>5. If you use a mic with low inherent self-noise and strong output,
>>  >>you can achieve good quality recordings with a recorder that has a
>>  >  >noisy pre-amp.
>>
>>And I hope people don't confuse price with "noisy" here. The lowly
>>HiMD tested is NOT an example of a noisy pre-- it has maybe  1-3dB
>>more noise but only at narrow selected bands?  That's out of the
>>~133dB range.
>>
>>Also note also that while preamp gain doesn't affect noise the way I
>>tested it, at max gain with all wrinkles showing,  more gain in the
>>sound file under quiet conditions enables more bit saturation and
>>more ability to do effective filtering, volume boosting etc in  post
>>etc. The HiMD has 5dB more gain than the 722 helping one get more
>>performance out of 16 bits rather than 24.
>>
>>Klas, Oryoki, anyone,.. Clobber me if you think I'm wrong on any
>>point(s). This is important stuff to get straight. Rob D.
>>
>>
>>
>>  >Thanks, excellent summary!
>  > >
>>  >>In practice, this seems to be true.  The Marantz PMD670 is a prime
>>  >>example of a recorder with noisy preamps (Marantz claims s/n -65dBA),
>>  >>but Martyn Stewart's recordings using Sennheiser MKE and Telinga mics
>>  >>sound great.
>>  >
>>  >Also in theory. It is just logics.
>>  >
>>  >>I guess the place I'm having trouble is in the notion of "over-riding=
"
>>  >>the recorder preamp.  Klas, do you mean that when a mic has a high
>>  >>mV/Pa, you don't have to turn up the volume of the recorder pre as mu=
ch?
>>  >
>>  >Yes. Exactly. If enough gain is produced by the "optimized" pre in the=
 mic
>>  >(minimum self-noise!!) - you don't need so much gain in the
>>recorder preamp.
>>  >
>>  >Klas.
>>  >
>>  >
>>  >>--oryoki
>>  >>
>>  >>
>>  >>
>>  >>
>>  >>"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
>>
>>
>>"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


________________________________________________________________________
________________________________________________________________________


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