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What is inductance (NOT impedance!) of typical dynamic microphone?
dusan:
I'm trying to create model of typical dynamic microphone, I don't have one, and I'm trying to find out what is typical inductance of dynamic microphone. Everybody only posts impedance, for example Behringer SL-84C has 250Ohm: https://mediadl.musictribe.com/media/PLM/data/docs/P0E7R/SL-84C_QSG_WW.pdf It's like closest guarded industry secret nobody wants you to know.
--- Code: ------*---sinewave--inductor--resistor---*---
|_____ capacitor___________________|
--- End code ---
What values should I choose for voltage amplitude, inductor, resistor and capacitor values?
Wolfram:
Here's a sweep of a a t.Bone MB-75, a cheap and cheerful SM-57 clone from Thomann. Impedance is specified as 300 ohm. It's a lot flatter and more resistive than I expected.
ejeffrey:
It's not really a simple RLC circuit because the mechanical parts of the microphone affect the electrical circuit due to back-emf. Those mechanical parts have frequency dependent behavior that isn't as clean as capacitors and inductors. So you can approximate it, but it's not going to be great.
Also, note that your model is potentially misleading. You show a voltage source as part of an RLC network. That's fine as far as it goes, you can define a lot of equivalent circuit networks. But if you are expecting that you can model it as an ideal frequency independent pressure-to-voltage converter modified by an RLC network that matches the microphone impedance, that's probably not correct. For that you need the overall sensitivity curve which is in the data sheet, and includes the transducer sensitivity as well as the circuit loading.
dusan:
What are those two curves? What's on the axis?
ejeffrey:
Magnitude in ohms and phase in degrees of the impedance vs frequency.
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