The impedance will be Re in series with Le (which is lossy) in series with a parallel RLC resonance circuit. In this parallel circuit
R= (Bl)^2 / Rms
L= (Bl)^2 * Cms
C= Mms / (Bl)^2
Where Cms is the compliance of the driver, Mms is the total moving mass of the driver, and Rms is the total mechanical resistive losses of the driver. In case of a closed box, it can be seen as if the box modifies Rms and Cms, so the effect of a closed box can be included by changing these values. Other kinds of boxed will need another type of circuit diagram than this.
HTH
R= (Bl)^2 / Rms
L= (Bl)^2 * Cms
C= Mms / (Bl)^2
Where Cms is the compliance of the driver, Mms is the total moving mass of the driver, and Rms is the total mechanical resistive losses of the driver. In case of a closed box, it can be seen as if the box modifies Rms and Cms, so the effect of a closed box can be included by changing these values. Other kinds of boxed will need another type of circuit diagram than this.
HTH
Siegfried Linkwitz has a sketch of the electro-mechanical model of a sealed woofer on his web page.
Subwoofer design
Subwoofer design
An externally hosted image should be here but it was not working when we last tested it.
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