DAN
> > Note 1: Some amateur equipment is capable of being accurately
>> calibrated; consumer MD recorders, for example, have repeatable
>> stepped input gains. A calibration workshop could travel around the
>> country and certify calibration of volunteers' systems (mike and
>> recorder combinations).
WALT
>I would not think that would fly very far. There is a established
>procedure for certifying noise meters that are being used where legal
>wrangling will be involved. About doubles the price of a meter to get
>one of these, and all it really amounts to is legal documentation all
>the way from some primary standard to the particular meter. But, without
>it anything that gets into court will die. And I'm sure the park service
>stuff will generate court cases.
I'm sure you're right about that. Do you think an amateur calibration
system might be acceptable for scientific work? I've spent my 35-year
audio engineering career getting professional results with consumer
and semi-pro equipment, and I know it can be done!
>...Your 2nd line would be for the recordists to have calibrators, but thos=
e
>cost a lot too. I'm not sure I'd trust consumer gear not to drift too
>much. Using a calibrator at the beginning and end of the recording would
>at least check that.
Here's another calibration idea: A portable CD player with a speaker
and a 20-foot string attached is sent around to recordists. The
player produces a broad-band noise signal that the recordist records
outdoors in a quiet location, creating a reference that includes both
level and frequency response (of course it isn't flat, but it's all
relative).
-Dan Dugan
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