Damping Factor


I firmly believe a quoted Damping Factor on Audio Power Amplifier outputs of 10, or possibly as low as 5 is perfectly adequate to ensure perfectly good quality sound reproduction from the majority of loudspeaker systems.
Can anyone enlightem me why particular emphasis and value is given to damping factors of 1000 or more for certain Solid State Amplifiers other than advertising value. A high Damping Factor is related to amplifier output impedance, and comes automatically with amplifiers having heavy feedback, not necessarily good ones.
poulkirk313e
Actually, it was the Macro Reference that had 30,000. In my opinion, damping factor means more, with the more acoustic watts that are desired from the low frequency driver. If you have a very powerful woofer (or perhaps several driven from one amp) in a concert sound reinforcement situation, you want all the damping factor and current reserve you can get.

For home hi-fi, you generally have specialized woofers with a long linear excursion designed around less absolute peak dB output in the first place, so they are inherently more forgiving, especially at the lower ouput levels that occur in the home.

Also, with smaller midwoofers (like those in every "box speaker"), their moving mass is so much lighter than larger woofers, that they can get by with less damping control from the amplifier.

A manufacturer called Meyer Sound Labs has a new active studio monitor speaker that employs the familiar servo feedback circuit on its woofer (but uses a microphone on a bar mounted in front of the woofer, rather than the consumer hi-fi method of using an accelerometer on the woofer's cone). They claim that this circuit allows faster decay time than a "typical electrostatic". That doesn't surprise me much, since larger esl panels are terrible at stopping, once they get started (every MLSSA plot that I've ever seen, in Stereophile and elsewhere, fully bears this out).
Noquarter: You're right about the MacroReference. I remembered that one was way up there, but since the Web, I don't keep as many spec sheets laying around any more.

I agree that high damping is a must wherever the moving mass--inertia--of the speaker cone is high. I find a lot of people are surprised, though, that you really have to figure the speaker wire in to get a complete picture of the damping, and that's usually going to overwhelm whatever the amp's damping spec is, so that it's almost negligible if one amp is 300 and the other is 5,000.
Crown Macrotech i amplifier has 5000 damping factor @8ohm. It has extra damping factor compare with other amplifires. Is 5000 DF harmful for any 4ohm load driver??
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The highest effective DF (for the purpose of damping motion of the membrane) is 1.5

It is because DF comes from dividing nominal speaker’s impedance by total impedance in the circuit. It is important to understand how damping of membrane works. When we apply positive voltage to "+" vs "-" speaker terminal membrane moves forward because of current flowing thru the coil (from + to -) in magnetic field. When membrane moves forward on its own same polarity voltage is generated on + to - speaker terminals, but current direction is opposite (from - to +), flowing from the speaker thru amplifier and back thru speaker( trying to move membrane backwards effectively braking forward motion). Speaker coil is still in the circuit and its resistive impedance is about 2/3 of nominal impedance. For that reason maximum obtainable DF is 1.5 (reciprocal of 2/3). We don’t wan’t to screw it up more so 10x lower source (amplifier) impedance is desirable. When it comes to driving varying complex speaker impedance it might be a different story, but there are many tube amps (including Atmasphere) that have DF around 1 and sound great. Searching for the amp that has DF>100 or selecting extremely thick cables is silly IMHO. On the other hand you might hear the difference, if you believe there must be a difference (placebo effect) - nothing wrong with it. If it works it works :)