Loudspeaker parameters
Electrical
Re := DC Resistance of voice coil
Le := inductance of voice coil. This parameter is strongly nonlinear with both frequency and excursion - in most types of analysis this property is assumed negligible and is neglected. In very large diameter multilayer coils this parameter can become large enough to affect response at and near the cutoff frequency. It also affects the shape of the impedance peak at Fs, causing it to be asymmetrical.
Fundamental Mechanical
Mms := Mass in kilograms of moving system including air load, The air load mass is affected by baffle size
Sd := Projected Area in meters squared of cone plus half the width of the surround
Cms := The displacement of the cone in meters for a force in newtons (actually nonlinear with excursion)
Bl := the cross product of magnetic field strength and wire orientation summed along length, for ordinary cone loudspeakers this is merely B*l = Average Gap field strength times length of wire in gap (also nonlinear with excursion)
Rms := Mechanical damping of cone and suspension at resonance. (nonlinear with frequency and excursion)
Small signal free-air parameters (Thiele/Small)
Fs := Resonance frequency of driver (impedance peak)
Fs=1/(2*pi*sqrt(Cms*Mms))
Qms ;= Mechanical Q of driver
Qms = 2*pi*Fs*Mms/Rms
Qes := Electrical Q of Driver
Qes = 2*pi*Fs*Mms*Re/Bl^2
Qts := Total Q of driver
Qts = Qes*Qms/(Qes+Qms)
Vas ;= the volume of air in cubic meters with the same stiffness as the driver when acted on by a piston of area Sd
Vas = Sd^2*rho*c^2/((2*pi*Fs)^2*Mms)
rho ~= 1.18kg/m^3
c ~= 345m/s
Note: 1 cubic meter = 1000 liters
Measurement of Thiele/Small parameters:
While there are some simple methods that require a function generator, frequency counter (these can be substituted by a computer soundcard with a sine wave generating program) a reference resistor and voltmeter to measure the T/S parameters, I would suggest that anyone serious enough to do it that way would better spend their time learning how to measure them with a free program like Speaker Workshop or ARTA (google is your friend, here) using a simple jig.