Damping Factor
A measurement of an amplifier's ability to control the motion of a speaker at the stop of transient impulses. Technically defined as the ratio of the load impedance to the amplifier's output impedance. The high output impedance of the amplifier enables it to absorb the back EMF generated by the voice coil. A damping factor greater than 10 is usually adequate, however amplifiers with damping factors up to several thousand are available. Note that damping factor varies with frequency as the load's impedance changes.