Calculation of the electrical input impedance of an electrodynamic loudspeaker
Question
By considering that the radiation impedances loading the two faces of the membrane can be reduced to two simple masses
, give the expression of the electrical input impedance of the loudspeaker
.
Plot the module of this transfer function relative to the frequency.
The electrical impedance of the loudspeaker is written:
with
A representation of the module of the admittance relative to frequency is the following:
This graph allows the identificatin of certain electro-mechanical parameters. In particular:
The module of the impedance tends towards the DC resistance
in low frequency.
The slope of the curve as frequency increases corresponds to the value of the inductance
.
The frequency of the resonance peak corresponds to the resonance of the mechanical part.
