What is Damping Factor, and Why Do I Need a High One?

Damping factor is something that most enthusiasts who have been around high fidelity for less than ten years know nothing about. Why you ask? From my perspective, it would seem that anyone interested in a high damping factor would not be looking for anything in the under $1000 category, as most amplifiers in that class have a poor one, and simply producing audio of any quality is a remarkable achievement.

this Threshold S500 has a damping factor of well over 1000:1…beauty, eh?

The term damping factor refers to a ratio of the internal impedance of the amplifier to the characteristic impedance of the speaker driven by it. Obviously this would vary widely, as each speaker has its own characteristic impedance, and also, since speakers are a reactive load, it would be hard to specify across the frequency spectrum. In order to be uniform, the speaker load of 8 ohms, purely resistive, is assumed.

Quality amplifiers will have a damping factor of at least 100:1. Many really exotic, and very high quality amplifiers will have a damping factor of 1000:1 or more.

By now, I’m sure many wonder why this ratio is called damping factor, and why anyone concerned with great sound should be concerned with it. Damping factor affects the way the music sounds, as it refers to how well ‘damped’ any cone movements are. The larger the ratio, the more capable the amplifier is of controlling the movement of the speaker drivers. It is most apparent in the bass, but has an effect all through the audible range.

When listening to a system with an amplifier of high damping factor, the bass will be extended, but very clean. The woofers will not overshoot, and any muddiness in the bass will be due to the program material, more than the amplification chain. This is not to say that an amp of high quality will make the bass of a Cerwin Vega (a speaker known for boomy, muddy bass) turn into the bass of a reference series speaker, but a marked change will be observed, and heard.

this Cerwin Vega is popular with the crowd that likes the tizz and boom sound, but a good amplifier will tame much of that boom!

As complete specifications are harder and harder to find for any audio or video equipment these days, it might be difficult to assess damping factors. Any piece of equipment that is worth your time will have a manufacturer willing to send you a more complete set of specifications, so do a little looking, or writing, and see what you find.

When talking about damping factor, it is imperative to know that each part of the amplification chain is significant. This is why quality speaker cable of sufficient size is necessary for quality reproduction. Now, some will tell you that huge rope-like wires are needed. While that would be nice, and WOULD make a difference, it is impractical, and most significant others would frown on both the aesthetics and cost of such a move. On the other hand, I would never think of using less than 16 gauge multistranded copper wire for any installation, and any move you can make upwards in size will bring dividends in sound. Some wire suppliers, like Monster, have larger gauge wire made to look as inconspicuous as possible, so that may be the ticket for your installation.

a couple of examples of high quality speaker cable, which helps maintain the high damping factor, AudioQuest, Kimber, and Monster all make great speaker cables.

Damping factor is not the be-all-and-end-all of amplifier specifications, but it goes a long way toward getting good quality sound.

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