John Curl's Blowtorch preamplifier part II

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#56,204
Elvee said:
OK for carbon mics, and condensers when operated purely in voltage mode, but dynamics react to dP/dt, not P. You cannot make a barometer out of a dynamic mic (unless it has a supraconductive coil, of course)
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Elvee
Yes and I admit it is more complicated than that.
The coil can register only dp/dt. But the diaphragm of the mic depending if it is closed or open back design will function as pressure sensitive or pressure gradient (i.e. velocity) sensing device respectively.
All diaphragms respond to delta p/delta t. Closed back design diaphragms work against a fixed back pressure, so delta p is of single polarity.
Open back design diaphragms work acc to the balance of front and back varying pressures, thus delta p is of a changing polarity.

scott wurcer said:
Great stuff George.
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You know where to look for B&K stuff Scott, yes? Also read Alan Blumlein’s patents:
GB 394325 (1931)
US 2062275 (1936)


I would think impulse response only makes sense in the noted case, what thinks you?
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Most probably yes. The only way to confirm it, is by experimentation (monitor the outputs of a p & u mic assy)

George
 
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#56,218
scott wurcer said:
I wonder how much it cost for the CEO of "Victoria's Secret" to get his >300T yacht classed as a pleasure boat by act of congress. 😱
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It took the congress committee to road test models in VS lingerie, to get "the feel" of it all. 😀

And they say politicians are lazy slobs, and yet, there they are, striving for the benefit of the community, testing to protect the public from potentially dangerous Chinese fabrics. 😀
 
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