naturerecordists
[Top] [All Lists]

Re: testing mic self-noise

Subject: Re: testing mic self-noise
From: Walter Knapp <>
Date: Wed, 28 May 2003 13:46:29 -0400
Dan Dugan wrote:
> Good tutorial on self-noise, Walt,

I've noticed a tendency in some discussions to make the leap from the 
mic spec directly to environmental noise levels without considering 
gain. I may have even contributed to that in the way I've said things. 
Figured it might be a good idea to correct that.

> A mike preamp with its input unterminated is usually noisier, 
> sometimes a lot noisier. A more realistic test for preamp noise is to 
> wire up a male xlr with a 150 ohm resistor between pins 2 and 3 to 
> use as a dummy mike. I'm not sure what to do with an unbalanced 
> plug-in-power input.

I would think a unbalanced input could be handled the same, plug in 
power is so small it would not be a problem. Though you might want to 
match the resistor to the impedance of the mic you are interested in. 
The resistor would go from Signal hot to Signal cold in any case. For a 
stereo miniplug input I guess you'd want to use two resistors so both 
channels are loaded. Probably the same on most XLR balanced 
recorders/pre's that have two channels.

Walt




________________________________________________________________________
________________________________________________________________________

<Prev in Thread] Current Thread [Next in Thread>
Admin

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU