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Re: Mics now? Re: preamps

Subject: Re: Mics now? Re: preamps
From: Rob Danielson <>
Date: Mon, 25 Apr 2005 16:09:35 -0500
At 12:04 PM -0700 4/25/05, Charles Bragg wrote:
>At 01:21 AM 4/25/2005 -0500, Rob Danielson wrote:
>
>(about the AT853)
>
>>sensitivty is 6.3 mV re 1 V at 1 Pa
>>   self noise is 27dBA
>
><snip specs list>
>         Thanks! Where did you find that stat?

googled,"Audio Technica 835"

>I notice that 27 is the difference between the Maximum SPL (135) and
>the dynamic range (108). Is this a coincidence, or can I use that
>formula for other mics?

As I understand it, signal to noise is based on -94 dB, 1 kHz at 1 Pa
so a mics self noise is the difference between this and the rating
for the 853: -67 dB, 1 kHz at 1 Pa or 27dBA.
>
>>>          Possibly unrelated question - on the indoor recording I got
>>>a 20 db spike above the hiss at 8200 hz which I did not hear at the
>>>time. It only became obvious when I filtered the hiss out and
>>>boosted the treble. Could this be some kind of mic feedback noise
>>>(the two mics were pretty close together and within each other's
>>>polar pattern)? It was present during the entire recording.
>>
>>Sounds like low batteries, check condition?  Rob D.
>
>         The rechargeable battery was at 2/3 so I put on the AA
>booster with a fresh battery. I ran the unit for a couple of hours
>*after* the recording, so I'm pretty sure the batteries were good.
>
>         -- Chuck
>
>         PS: does anyone know the noise specs for the MD-DR7?

I've never encountered mic input noise specs given for Sony or Sharp.
The Sharp manual (like most MD's) is in the minidisc community archive
http://www.google.com/url?sa=3DU&start=3D1&q=3Dhttp://www.minidisc.org/manu=
als/sharp/sharp_mddr470.pdf&e=3D10053

Maybe try other mics to see if the spike goes away or changes? Rob D.

>
>
>=3D=3D=3D=3D=3D=3D=3D=3D
>Chuck Bragg, Pacific Palisades, CA
>Membership, Newsletter, Web manager
>Santa Monica Bay Audubon Society
>www.smbas.org
>=3D=3D=3D=3D=3D=3D=3D=3D
>
>[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
>
>
>
>


--
Rob Danielson
Film Department
University of Wisconsin-Milwaukee


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