<< I feel that there are still many important discoveries and
improvements to make in far field recording in quiet locations.
Perhaps some radical ones.>>
We are currently at the limit of what analog circuitry can achieve
noise-wise. The hurdle to further reductions in the noise of an
amplifier circuit is the molecular noise inherent in any conductor
carrying electrons at a temperature above absolute zero. Depending on
who is describing it, that limit is around -128db to -130db. So
there's not much room for improvement there. However, in the strictly
experimental arena, I've heard of work done directly addressing ADCs
with the output of the microphone, with potential improvements going
scores of decibels beyond what any analog amplifier can achieve. Of
course no microphone is that quiet, but it may eventually be possible
to eliminate the preamplifier as a source of noise degradation. I
would also look to alternative microphone designs in the future,
wherein diaphragm displacement can be measured by a laser, rather than
having to generate an alternating current, or varying capacitance. And
of course the microphone of the future will output digital, not
analog. Neumann has this already.
Scott Fraser
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