A simple explanation of dampening factor

[Pelliott321]

https://www.youtube.com/watch?v=idxT7VVYyxo&feature=em-uploademail

[dberning]

What is not mentioned is that the dc-resistance of the voice coil should be added to the output resistance of the amplifier to get the true damping. This is why going below a couple of ohms of output resistance in the amplifier itself begins to have very minor effects as the speaker dc resistance dominates.

Another thing to consider is that subjectively, the highest damping may not give the best sound as some speaker drivers are overdamped and the bass can sound dry.

[tomp]

Absolutely correct on the effect of the driver DCR. The only exception is a servo system where the amp can output a larger correcting voltage to offset the driver overshoot. As far as woofers not being flat, reducing damping will provide more bass but in my experience it is sloppy. Better to use EQ to help anemic woofers as long as you don't overdrive.

[SoundMods]

What is not mentioned is that the dc-resistance of the voice coil should be added to the output resistance of the amplifier to get the true damping. This is why going below a couple of ohms of output resistance in the amplifier itself begins to have very minor effects as the speaker dc resistance dominates.

Another thing to consider is that subjectively, the highest damping may not give the best sound as some speaker drivers are overdamped and the bass can sound dry.

I recall reading a white paper published back in the '60s. It talked about the new solid-state (SS) amplifiers and "damping factor." That low source impedance, a feature if you want to call it that, of direct-coupled SS amps can have a negative effect on the sound because the inductive reactance of the voice coil together with the crossover components can enable ringing because of what amounts to a dead short connecting the components. In my own experience -- my home theater system -- I have a SS receiver driving full-range speakers that drop well below 4-ohms nominal. The receiver user-manual warning was that it did not or could not operate reliably below a 6-ohm load. So I added a 150-watt, 3-ohm resistor in series with each speaker. What I didn't expect was that the mid-range and especially the bass tightened up. WTF?!

Others in my circle of friends have tried that gimmick with the same result. My main "he-man" audio system has a network tied to the speakers that essentially puts 10-ohms in series. I did many a A/B comparison with the speakers sounding better overall, tighter and more open, with the network in place. My amplifiers? CARY 805Cs that are SETs using 845 transformer-connected triodes.

And yes -- it goes against everything anyone has ever said or written about the subject. It is what it is.

[tomp]

One of the great tragedies of modern science is that every day beautiful theory is shattered by ugly old reality.

[SoundMods]

One of the great tragedies of modern science is that every day beautiful theory is shattered by ugly old reality.