Damping Factor
Damping factor is the nominal loudspeaker load impedance divided by the amplifier’s output impedance. It is a ratio with no unit.
Impedance is opposition to alternating current. At a stated frequency, an 8-ohm reference load divided by 0.04-ohm output impedance gives a damping factor of 200. The output impedance is 0.04 ohms.
Damping Factor — Power Amp
At the same load and frequency, higher damping factor means lower output impedance. This reduces the effect of changing speaker impedance on the balance of bass, midrange and treble delivered to the speaker.
Compare figures at the same reference load and frequency or frequency band. “Above 200” is a lower bound, not exactly 200. The source impedance seen by the speaker combines amplifier output impedance and speaker-cable resistance. Adding this cable resistance reduces effective damping factor. The speaker itself also matters: the amplifier’s number alone cannot rank sound quality, and ever-larger values do not promise unlimited improvement.
Sources
- Damping factor and amplifier output impedance — Benchmark Media Systems
- Damping factor and the loudspeaker circuit — Audiofrog
- M-5000 specifications: qualified damping factor — Yamaha