Uh oh! Someone used my name!
> Going back and reading Eric Benjamin's AT3032 posts personally I can't
see anything that supports a
> claim for 8dB self noise for the AT3032's.
Eric stated that the AT3032 were slightly quieter than the MK2's
> so we
are relying on the MK2's matching the manufacturers spec of 11dB to
derive a figure a sub 11dB
> figure the AT3032. My experience in
comparing with Andrew Skeoch's MKH20 SASS rig is that the MKH20
> are a
quieter mic. Walt Knapp's comparisons of the AT3032 and MKH20 in SASS
rigs seems to indicate
> the same thing, and I feel this sets the lower
limit for the AT3032 at around 11dB self noise.
The basis for my original statement of 8 dB self noise for an AT3032 was that I
had measured one as having 8 dB self noise. I have very good facilities for
measuring microphone self noise and I can generally do a pretty accurate job
down to about 5 dB or so. Below that, the impact of environmental noise may
limit my ability to measure the true self noise of the device. Note that the
usual sort of errors work in the direction of causing the measurement result to
be high, not low.
Could I have been in error in my measurement? Of course I could! But I don't
think so. I was so surprised by the result that I did the measurements over
again, and then I did a listening test to confirm. As it happens, the Schoeps
Mk2 microphones are very consistent in terms of their self noise. I have
measured three of them and they were all within a fraction of a dB of the
specified 11 dBA. The reason for this is that a particular resistor in the
circuit limits the self noise, not the FET. And the AT3032 was noticeably
quieter than the Schoeps Mk2.
Could other samples of the AT3032 have different self noise? Of course. I
haven't analyzed the AT3032 circuit so I don't know what limits the
performance. It could be pretty variable. That could explain why AT chose to
rate the microphone as having 16 dBA. I dunno. I only measured the one
sample. I do have access to about a half dozen of these microphones so I could
sit down and measure the whole crop.
But that doesn't answer the question about the AT4022. Lack of funds prohibits
my purchasing one just out of curiosity. But if there is someone in the SF bay
area who has one and would like to have it measured, I would be happy to make
the comparison.
Eric
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