At 8:56 AM -0700 3/26/09, Scott Fraser wrote:
><< 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
>
Hi Scott--
Absolutely. I agree that there will probably not be huge improvements
in signal to noise performance and there will always be an a-d step
somewhere. Maybe we might be able to insert digital processing so
early that it interacts with the physical movement of the mic
diaphragm or just air itself? One would hope that the transducer
(speaker) side will continue to be improved upon somehow,.. but
please, not by bypassing air and the ears as I've read about in
places. =3D-O
In dialogs on other lists, one is continually reminded of how unusual
it is to be concerned with techniques for recording sounds coming
from "miles" and interacting with "yards" of complex environments
opposed to addressing "feet" from musical instruments within concert
halls or recording studios. Classical music is built-upon enforcing
resonance; the same phenomenon obscures spatial transparency in large
environments. Our ears are able to cut through these complex wave
interactions and track subtleties; microphones are often humbled by
them. I suspect there could be a new direction in tools that are more
appropriate for the atypical acoustic settings we are embracing.
Maybe I'm wrong, but it seems like there haven't been that many minds
addressing these challenges of scale as yet. What is it,.. about
40-50 years since folks started cranking up the gain and (sort of)
liked what they heard? Rob D.
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