Such a lot to comment on here.
First of all, I want to say that I like to use
lavalier microphones for nature recording, in part
because they are so durable. I happen to use the
Countryman B3 microphones mostly, because they cost
much less than the DPA 4060 microphones. And I am
amused by the fact that Carl Countryman demonstrates
his microphones by having the microphone sitting in a
cup of coca cola, and then pulling it out and showing
that it still works just fine. (YMMV)
And it's true that small electret microphones do not
perform up to the standard of the better studio
microphones. Although the best of the small electrets
are better than some average studio microphones, and
that is remarkable. I don't believe that the
performance of most of these microphones is limited at
all by the physics of microphones. I think that they
could be substantially improved if noise were the
specification that people care about. But lavaliere
microphones are generally made from capsules that were
either designed for hearing aids, or are the better
types that are the same ones as used in cell phones
and answering machines. Noise just isn't something
that the big makers of electret microphones care much
about. There are a few exceptional ones.
The company that you refer to below is "DPA" (Danish
Pro Audio). And the organization that hasn't yet
issued standards for microphone measurement is the AES
(Audio Engineering Society).
> there is no method of showing where
> in the spec, noise will occur
This is true. The use of A-weighting (the 'A' in dBA)
helps to concentrate the measurement in the high
frequencies, where the noise is most likely to be
heard. It works pretty well (for an 80 year old
standard!), but one could wisht for better.
I think that DPA's specification for the 4060 is
probably pretty close to spot-on. Not better than
that, and not worse than that. I don't want to
comment too much on manufacturer's measurements of
their own products. I suppose that I'd like to think
that what they print is at least close to the truth.
I'd bet that if I take a sample of a DPA 4060 into my
lab, that I'd measure something very close to 24 dBA.
Some might be a dB better, some a dB worse.
We'll see, because I'm going to do that experiment
tonight. I'll measure a couple of DPA 4060 mics and a
couple of Countryman B3 mics.
There is one other nugget that I would like to impart.
The difference between two levels of microphone noise
sounds bigger than it measures. What I'm saying
(trying not to use too much jargon here) is that 2 dB
of difference, which would be very small in the case
of the loudness of a voice, sounds like a bigger
difference when it's noise and it's very quiet.
Eric
--- lilyplants <> wrote:
> from what ron and scott are saying I understand, low
> self noise is 17 dB(A) or quieter, and
> there are no such quiet very small mics because as
> the diaphragm size decreases noise
> increases.
>
> bruce meyers, president of DBA, US, explained the
> browian movement as the noise of air
> molecules bumping together. when the space between
> the diaphragm and metal is
> decreased, the bumping is amplified.
>
> he also said a dirty little secret is that there are
> no ADS (?) standards for testing mic self
> noise. DBA is working for the creation of standards.
> six mic manufacturers got together to
> test their mics. each used their own equipment and
> methodologies. DPA which uses the
> best testing equipment, he said, tested their mics
> at 20 dB(A), the other five, measured 10
> dB(A). The five companies tested the DBA mic or mics
> at 10 dB(A) with their equipment
> and methods. DBA tested the others at 30 dB(A) with
> their equipment/methodology. He
> said you can estimate the DBA mics to be 5 to 10
> dB(A) quieter than other mic specs.
>
> Bruce also said there is no method of showing where
> in the spec, noise will occur. the
> human ear hears more in the mid range.
>
> he recommends the 4060 for nature recording which
> has 23 dB(A) according to their
> standards.
>
> What do you think about his comments on DBA tests?
> It would indicate the 4060 mics are
> quiet according to the 17 dB(A) or quieter
> definition.
>
> Lily
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