Damping factor
![](/Images/godic/202501/07/Source_and_load_circuit_Z3155.png")
In an audio system, the damping factor gives the ratio of the rated impedance of the loudspeaker to the source impedance. Only the resistive part of the loudspeaker impedance is used. The amplifier output impedance is also assumed to be totally resistive. The source impedance (that seen by the loudspeaker) includes the connecting cable impedance.
The load impedance ![Z_\mathrm{load}](/Images/godic/202501/07/60825d63d408c72ce7996413949c156b3155.png")
(input impedance) and the source impedance ![Z_\mathrm{source}](/Images/godic/202501/07/247b6572f2f9c46fd3f60d4626d315c73155.png")
(output impedance) are shown in the diagram.