> Regarding the noise, there was a detailed discussion about the
> measurements in the micbuilders mailing list:
> http://tech.groups.yahoo.com/group/micbuilders/message/12382
Shaya,
If you want a precise noise comparison, put two mics under a pile of
bedclothes and listen to the hiss. That's real :-)
My fears were well founded, this noise figure is meaningless according
to this link. The mic noise we hear is produced mainly by the mic
capsule, not the following amplifier which is what was being quoted.
Non-technically, air is noisy and this includes the air inside the
capsule, and only a fraction of the wanted sound energy is used by the
capsule which further increases the "excess noise".
Even more non-technically, it is a noise figure which does not relate
to a mic in real use.
"Self noise" is a non-defined term but must include the whole
microphone, and "excess noise" is the total noise over the thermal
noise of the air. Air hisses by itself. Suspect any noise figure below
23 to 25 dB ref ITU-R 468 or a similar standard.
Beware of all noise specs, especially noise specs which don't quote
"excess noise" and 468 weighting and which is a precise definition.
David
David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce
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