The dampening factor is the loudspeaker impedance divided by the output amplifier impedance. As an example, an 8 Ohm loudspeaker and an amplifier with 1 Ohm output impedance result in a dampening factor of 8. Using an amplifier with 1/10 Ohm output impedance results in a dampening factor of 80, and 0.01 Ohm in a dampening factor of 800. Traditionally, an 8 ohm loudspeaker is used in the calculation. For a 4 Ohm loudspeaker, the real dampening factor is 4, 40 and 400 for the same 3 amplifiers. But giving the dampening factor for 2, 4, 8 and 16 Ohm loudspeakers would waste space in the brochures, so only 8 Ohm is specified.