If I have a loudspeaker with a nominal impedance of 8 ohms connected directly to an amplifier whose output impedance is 0.01 ohms and there is no intervening wiring or crossover coils, the damping factor experienced at the loudspeaker would be 8 divided by 0.01 or 800. Now let’s impose 0.19 ohms of cable and crossover impedance between the speaker and the amplifier. The resulting damping factor delivered to the loudspeaker is 8 divided by a total of 0.2 or 40. Quite a come down from 800, at least in the perception of some. Then again, as long as the damping factor delivered to the driver is 20 or more, things are pretty well in hand. What if the nominal impedance of the driver were lower? A 6-ohm driver would experience a damping factor of 30, for a 4-ohm driver, 20. What if the intervening wiring were longer and/or of a more narrow gauge such that the total impedance between amplifier and driver were doubled? The damping would fall to 20, 15 and 10 respectively.

What effect does the amplifier’s damping factor have on this equation? If it were ‘infinite,’ or had an impedance of zero, and the wiring impedance were still 0.19, the delivered damping factor would be 42, 32 and 21 respectively. What if the amplifier’s directly connected damping factor were 400 into 8 ohms having an output impedance of 0.02 ohms? Damping factors would be 38, 29 and 19 - hardly any change in the damping delivered to the loudspeaker. What if the amplifier’s directly connected damping factor were much less, say only 100 into 8 ohms having an output impedance of 0.08 ohms? The ‘delivered’ damping factors would be 30, 22 and 15.

In any case, the bottom line: if the impedance of the wiring is on the order of ten, twenty or forty times more than the output impedance of the amplifier, the impedance of the wiring is ten, twenty or forty times more important than the damping factor of the amplifier itself. As a buyer, the difference between an amplifier with a damping factor of 800 and one with a damping factor of 400 is negligible. On somewhat lengthy speaker cable runs, the difference between 10, 12, 14 or 16 gauge wire or their equivalents would be much more significant to the damping actually delivered to the loudspeakers.