Impedance: The AC resistance that varies with frequency, measured in ohms.
Re: The DC resistance of the driver measured in ohms.
Le: The inductance of the voice coil measured in millihenries. This is a measure of the back EMF in the coil. Fs: Resonant frequency in free air of the driver in hertz.
Qms: Mechanical damping.
Qes: Electrical damping.
Qts: Quality factor incorporating the inverse of Qms and Qes.
Mms: The total moving mass of the cone, the coil, half the surround and spider.
Cms: The compliance of the speaker. The stiffness of the surround and spider.
Sd: The effective area of the cone; the cone less the surround.
Bl: Flux density (B) x length of the coil (L) = the strength of the driver motor in tesla metres (T·m).
Vas: The compliance of the air in the cabinet that matches the compliance of the speaker.
Xmax: Maximum distance the cone can travel without distorting.
Vc: Diameter of the voice coil.
SPL: Sound pressure level.