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Re: Mics now? Re: preamps

Subject: Re: Mics now? Re: preamps
From: Rob Danielson <>
Date: Mon, 25 Apr 2005 01:21:45 -0500
At 1:29 PM -0700 4/24/05, Charles Bragg wrote:
>         I do have noise somewhere but can't be sure if it's mic 
>noise, preamp noise, and/or playback amp noise. I use a pair of 
>SoundPro cardioids built with Audio Technica AT853's, and a Sharp 
>MD-DR7. Most of the time there is enough background noise outdoors 
>to hide any system hiss. Recently I made an indoor tape and when the 
>environment was quiet I heard a *lot* of hiss. I play back the files 
>into my computer sound card - which seems to record other sources 
>without adding hiss.
>         The self-noise specs are impossible to find, even on the AT site.


sensitivty is 6.3 mV re 1 V at 1 Pa
  self noise is 27dBA

FEATURES:
* Element-Condensor
* Polar Pattern-Cardoid
* Phantom Power Requirements- 9 - 52V, 2 mA typical
* Frequency Response- 30 - 20,000 Hz
* Switch- Flat; roll-off
* Open Circuit Sensitivity- PHANTOM: -44 dB (6.3 mV) re 1V at 1 Pa
BATTERY: -45 dB (5.6 mV) re 1V at 1 Pa
* Low Frequency Roll-off- 80 Hz, 12 dB per octave
* Impedance- PHANTOM: 200 ohms, BATTERY: 270 ohms
* Weight-.4 oz (410 g)
* Maximum Input Sound Level- PHANTOM: 135 dB SPL, 1 kHz at 1% T.H.D.
BATTERY: 121 dB SPL, 1 kHz at 1% T.H.D
* Output Connector- XLRM-type
  * Signal to Noise Ratio-67 dB, 1 kHz at 1 Pa
* Battery Type- 1.5V AA/UM3
* Battery Current/Life- 0.4 mA/2000 hours typical
* Switch- Off/on-flat/on-roll-off
* Power Module- In-line
* Dynamic Range (Typical)- PHANTOM: 108 dB, 1 kHz at Max. SPL
BATTERY: 94 dB, 1 kHz at Max. SPL



>Likewise for the DR7. So, the question is, how do I upgrade other 
>than by buying something new and hoping it's quieter? Where do I 
>find the specs?

Shure 183's at 40 mv/Pa sensitivity and 23 dBA self noise should 
provide more signal with less noise.

>         Question - do the new HiMd units allow you to copy ATRAC 
>files to your computer without playing them back?

direct digital transfer? yes.

>That would eliminate one possible source of noise.
>         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.

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

-- 
Rob Danielson
Film Department
University of Wisconsin-Milwaukee

[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
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