Damping Factor... How important is it?

[assessor43]

How important is an amplifiers damping factor in relation to speaker choice? I was curious because some speaker designs seem to be made for low watt SET amplifiers while others like Magnepans seem to be power hungry. Does an amps damping factor have a effect on sound and speaker efficiency?

 

[analogsa]

Damping factor has no effect on efficiency but has an effect on frequency response in the bass. How significant this is depends upon the speaker design and its impedance characteristic. Impossible to make any general statements.

 

[assessor43]

I guess what I am asking is if i am looking for a pair of speakers and my amps damping factor is greater than 14, is there a speaker, or "speakers" that work best with that damping factor?

 

[analogsa]

The vast majority of bass reflex speakers are not very happy with a DF of 14. Horns don't care much.

 

[DonH50]

It depends on the speakers. Low damping factor means high amplifier output impedance, meaning the amp is going to vary more with speaker load than one with higher damping factor. Speakers with minimal impedance variation over frequency are usually the best match for amplifiers with low damping factor. My old Maggies are an example. Many conventional speakers exhibit wide ( if not "wild") impedance variations over frequency and as a result the amplifier is going to change their sound.

Note the change could be positive or negative; you may like the frequency response resulting from an amplifier with poor (low) damping factor into your particular speakers. Or not.

Here is a short article describing the effect: https://www.whatsbestforum.com/thre...esponses-into-speaker-loads.8103/#post-139289

HTH - Don

 

[Alrainbow]

I just asked ralph this same question. but as he makes otl amps im
curious. I’m not goofing on him he is a very smart designer

 

[analyzer]

The impedance module and phase of the speakers are decisive in order to choose the perfect power amp partner, especially for the control and definition in bass region.
In most cases I suggest (in my esperience) a DF value from 50 to 300... following a rule that in ancient times said "in medio stat Virtus".
Too low DF will work for some old speakers especially High efficiency or Horns...
Too high DF (sometimes also over 1000 declared by many D-class amps and also proudly waved by some brand of class A & AB amps) may reveal a too much overdamped bass in most cases. Don't forget that an Uber-high DF can be obtained only by an eccessive amount of negative feedback in some points of the circuitry... and this is usually not good for an overall satisfying sound...
That said I must observe that many brands don't declare It at all or in better cases points a specification expressed at 1Khz when It would be necessary a graphic showing the overall curve toward the entire frequency spectrum.

 

[AMR / iFi audio]

The damping factor is a result of a division of load impedance and amplifiers' output impedance. We want our amplifier to be a perfect voltage source, which means it has zero output impedance. It means that output voltage stays the same despite differences in load (eg. different speakers). What zero impedance means is that with a certain voltage output amplifier can deliver infinite current. Well, that is never the case as we all know. Usually, amplifiers' output stage limits the current capability more than the output impedance.

It's different with tube amplifiers that have naturally higher output impedance. That is a factor why most tube amps prefer stable impedance in speakers. They have trouble with big drops of speakers' impedance because their response is "slowed" by their own output impedance. To make it a little clearer: if you plug speakers rated 4Ohms to 4Ohms tap in a tube amp you want the speaker to be 4Ohm regardless of the frequency. Some speakers are like that, some aren't.

 

[Alrainbow]

wasent there one maker of amps who clamimed a negative imp on the output ? thought luxman maybe . what i do know this topic is in part why some amps sound dark or thin with a given speaker . the class a of a given amp also plays in the sound too.

 

[AMR / iFi audio]

wasent there one maker of amps who clamimed a negative imp on the output ? thought luxman maybe . what i do know this topic is in part why some amps sound dark or thin with a given speaker . the class a of a given amp also plays in the sound too.

Never heard of it before. It may be some kind of wordplay on negative feedback. Negative feedback lowers the output impedance be a feedback factor. That's how solid-state amps can get it so low in measurements.

 

[Alrainbow]

Ok I’ll find who said this. I’m not saying I have a clue how only words. lol

 

[Alrainbow]

Ok I’ll find who said this. I’m not saying I have a clue how only words. lol