[sm4r2d2]

HI, I would like some discussion on the importance of an amp's damping factor. In particular how it affects speakers- monitors- full range- and subwoofers.
  Spending time looking at stuff on e-bay I noticed that Mac stuff only has a rating of 100, while my current amps are rated at 1000 into 8 ohms.
   Do speaker designers consider this when designing? I haven't noticed ratings on plate amps for subwoofers either, and it seems that it should make a difference in sound.
   But I don"t know so I defer to those who do.
    Thanks ---RichardDC---

[warnerwh]

Any well designed SS amp damping factor isn't usually much of an issue. With tube amps it is an issue. The bass will become soft and rolled off.  Don't read too much into amplifier specifications.  They are important but there is alot more to it.

[Bob Wilcox]

Over a 6 Moons there is an artlcle about the First Watt amp that discusses the how differences in damping factor effect speakers.

Some speakers need a low damping factor.

Bob

[eico1]

With tube amps it is an issue. The bass will become soft and rolled off.

Is that due to the damping factor or just due to the other issues a tube amp might have that might roll off the highs and lows?

There is a technical article by Dick Pierce floating around usenet on the topic.

steve

[avahifi]

We once posted a damping factor specification for our first highly regarded product, the Double 400, years ago.

Damping factor:

Unit should not get wet.



Frank Van Alstine

[Levi]

I always thought that Damping factor is or was synonymous with Torque.  Specifications is not the ultimate measure in performance.

Some thoughts:
Torque vs. Horsepower.  Damping factor vs. watts.

[avahifi]

Actually damping factor is the ratio between the speaker load and the output impedance of the amplifier in question.

In the old days, the output impedance of many vacuum tube amplifiers were one ohm or higher.  Into an eight ohm load, this resulted in a damping factor of eight.  Into a four ohm load, a damping factor of four.  In addition, the voltage divider formed by the amplifier output impedance in series, and the load impedance in parallel caused significant gain reductions in the system, one fourth of the power could be used up heating the output transformers instead of driving the speakers.

In modern amplifiers, with very low output impedances, damping factors are always very high, and these issues are not musically important.

One reason that "damping factor" seemed so important in the old days was that this measurement seemed to corrolate with the "control" the amp had over the speakers.  Actually the fault was being assigned to the wrong cause.  A high damping factor amplifier was usually just a lousy design, the "number" not being a significant factor, other than an indication of a lousy design.

With a modern amplifier with an output impedance of a small fraction of an ohm, the "damping factor" specification is simply not an issue that relates to musicality at all.  Its just a carryover from years ago.

A modern amplifier with poor bass control and mud and boom likely just has an underdamped electronic resonsance built in, often by trying to be DC coupled from in to out (a very bad idea).  These days, its still not the damping factor that is important, its the integrety of the electronic design.

Frank Van Alstine

[sm4r2d2]

OK  I was under the impression that a damping factor relate to the control of a speakers start and stop speed. I think I read somewhere that it had more importance in the lower range. I was wondering if it had more importance than total watts , in say a subwoofer.
 Does this mean that high wattage is more important then in choosing an amp for a subwoofer or a full range speaker, design being equal in quality? Or is a plate amp equal to an amp designed for full range use?
 Thanks---RDC---

[BeeBop]

There is an article in one of the Bryston newsletters about this. Recommends improving speaker control with high damping factor amps by keeping speaker cable lengths as short as possible (well it's complicated - read the article). I shortened the Radio Shack 12 guage copper cables I am using (by about half) with my Bryston 3BSST and sure enough, better imaging, soundstage and greatly reduced sibilance (I had thought the problem was my source). I am now on the hunt for some good quality speaker cables and am no longer skeptical about speaker cables. There are a couple of other articles in the Bryston newsletter archives which discuss this - click here and here. Damping factor seems to have been elevated as an issue by Bobby Palkovic at Merlin Speakers who is telling people *that high damping factor solid state amplifiers do not get the best performance out of his highly regarded speakers*. Would be nice to see a response from speaker makers for whom this is not an issue - not everybody wants to jump on the toob wagon. In my case, toobs are just too high maintenance.

* edited

[art]

Damping factor is an overrated specification. Look at the wire inside of your speaker, and the ohmic losses in your woofer's LPF. Then tell me how important it is. Ditto for THD. Another overrated spec.

I have heard some amps with excellent sounding bass that had what many would consider to be a poor damping ratio. Getting the bass to "sound right" requires more than high damping factor and a boatload of caps in the power supply.

Pat

[WEEZ]

I am glad that two engineers (Frank and art) have weighed in on this subject. As art said, there are amplifiers with great bass that have rather low damping factors. And Frank indicating that in most cases- it is no longer much of an issue.

From a non-engineering perspective, (mine   ), it is still a matter of synergy between an amplifier and a given speaker. Some amps just don't sound right with some speakers. BeeBop mentioned the Merlin speakers. As a Merlin owner (TSM-MM), I can attest to the fact that a highly 'damped' sounding amplifier pushing the highly 'damped' Merlins is not the best sonic match. The combination sounds 'skinny' and extreemly 'tight'. While other amplifiers sound more 'relaxed' and natural.

Perhaps it is not the damping factor, or output impedence, but the ratio of even-order harmonic distortion to odd-order distortion?. Or, maybe something else?. Maybe some amplifiers have so much negative feedback applied that the 'life' is sucked out of the system?

It would also seem to me that low resistance cables should be a good thing. The less you squeeze the garden hose, the less 'tight' the sound should be. Maybe not, I don't know. Nor can I explain exactly what I'm saying   !

It's just that when someone says "amplifier A is better than amplifier B"; it should be taken in the context of the cables and speakers used. Maybe amplifier A sounds fine with speaker X; but with speaker Y- it sounds like shit. That doesn't make amplifier A a shitty amplifier. Or does it?

If it were easy, everybody would own the same stuff and there would only be one amplifier company.

WEEZ

[BeeBop]

Yes you are right. Bobby Palkovic takes a whole system approach and produces excellent results for his customers. Would be helpful to get comments from other speaker makers who take the same approach.

[WEEZ]

Indeed.