damping factor

[rollinrocker]

What excatly determines an amplifiers damping factor? I understand that generally speaking, the higher the damping factor the better control an amp has over the speakers bass output. That said, why do some designers choose a damping of 1000, while other (well respected and no less expensive) designs will use a factor of 200? It has nothing to do with financial restrictions, as i've seen high priced amps with high and low damping factors.

 

[gene]

Damping factor is an over abused and over used term and beyond a certain number (around 100 or so) becomes a nebulous specification just like anything else.

Damping Factor is a ratio of loudspeaker impedance to amplifier output impedance. Even if you get an amplifier with a damping factor of 1000 as you quoted, a few feet of speaker cable will nullify that advantage.

I suggest the following reading:

Damping Factor Effects on System Response

5 Myths in Audio Dispelled

Audioholics Amplifier Testing Procedure

 

[highfihoney]

Damping factor is an over abused and over used term and beyond a certain number (around 100 or so) becomes a nebulous specification just like anything else.

i agree that damping factor is overblown after a certian point but can you tell us what the difference would show up as when using 2 solid state amps with all specs being equal except damping factors with one amp having a factor of 30 & the other having a factor of 100?

 

[rollinrocker]

ok,

lets agree its an overblown spec. Why do some designers go to the trouble of achieving a higher damping factor? Is it infact any trouble at all? What excactly does an engineer do to an amp to create a higher or lower damping factor?

 

[highfihoney]

ok,

lets agree its an overblown spec. Why do some designers go to the trouble of achieving a higher damping factor? Is it infact any trouble at all? What excactly does an engineer do to an amp to create a higher or lower damping factor?

good questions, hopefully gene has answers because im clueless as to why.

 

[Buckeyefan 1]

ok,

lets agree its an overblown spec. Why do some designers go to the trouble of achieving a higher damping factor? Is it infact any trouble at all? What excactly does an engineer do to an amp to create a higher or lower damping factor?

Crown prides itself on high damping factor amps. That's not to say they're correct, but here is their explanation:
http://www.crownaudio.com/pdf/amps/damping_factor.pdf

This link shows that speaker gauge may play more of an important role in damping factor than does the amp itself.
http://www.prosoundweb.com/studyhall/lastudyhall/df.pdf

They seem to agree here:
http://en.wikipedia.org/wiki/Damping_factor

You must have missed this thread. This topic was just discussed not too long ago:
http://forums.audioholics.com/forums/showthread.php?t=18214&highlight=damping+factor

 

[MacManNM]

What excatly determines an amplifiers damping factor? I understand that generally speaking, the higher the damping factor the better control an amp has over the speakers bass output. That said, why do some designers choose a damping of 1000, while other (well respected and no less expensive) designs will use a factor of 200? It has nothing to do with financial restrictions, as i've seen high priced amps with high and low damping factors.

In general unless you have some exotic load, a damp factor >10 will sound the same as an amp with a factor of 10000000. Some amp makers have very high ratios because they think people are more likely to buy their product because it will sound better. It is all about the design and the source impedance of that design.

 

[mtrycrafts]

i agree that damping factor is overblown after a certian point but can you tell us what the difference would show up as when using 2 solid state amps with all specs being equal except damping factors with one amp having a factor of 30 & the other having a factor of 100?

Nothing will happen. If that DF was so important, there would have been an awful lot of positive outcome from DBT tests of amps over the years. There are no such data and the ones where there are audible differences, it was not the DF that caused the differences, but other issues.

I bet these two amps in this DBT, readily available on line, was even worse than what you posted:

http://groups.google.com/group/rec.audio.opinion/browse_frm/thread/664b8681ab141263/3fd91bcb6a1522a0?hl=en&lr=&ie=UTF-8&oe=UTF-8&rnum=1&prev=/groups?q=sunshine+stereo+yamaha+abx+nousaine&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=501fl6%24ac3%40oxy.rust.net&rnum=1#3fd91bcb6a1522a0

 

[mtrycrafts]

ok,

lets agree its an overblown spec. Why do some designers go to the trouble of achieving a higher damping factor? Is it infact any trouble at all? What excactly does an engineer do to an amp to create a higher or lower damping factor?

Marketing pressures, plain and simple. But, if it was that important, where are their DBT results to show that it is important. Unlike the CRC that DBT tests and researches speaker response, amp makers do not do any DBT. I wonder why? Why would anyone pay 10X the $$$ for no audible differences when that is the major reason many purchase.

 

[mulester7]

.....this is hilarious....the nay-sayers quickly run and grab their stored links like the links were funeral suits in a closet....some even seem to have a catch-all pet link that they pull out for "everything"....science and blindfolds have misled more people than helped, on way too many comparisons, and how sad ears aren't used exclusively for judgements of any comparison of sound quality....when you compare "any two like components" for sound quality differences, hearing one perform at a different time than the other, even if it's only seconds apart, reveals little or nothing when the differences are arguable to start with....do you want to compare the damping factor differences between two amps?....have them both powering the same brand and type speakers, at the same time, using, of course, the same source and pre-amp, and walk back and forth between the sound fields of the speakers....you don't want to do that?....hey, whatever, who really cares?....just keep on pulling out the links/suits whenever the subject comes up as is currently done....my method of testing is your best, and probably only, shot....I used this method of testing to compare the damping factors of a McIntosh MC2200 with rated damping factor of 100, to a Crown K2 with a rating damping factor of 3000....the sound of the Crown could be compared to a tight clean slender person, and the Mac amp to Fat Albert....room acoustics had "nothing" to do with it, as the space between the two sets of speakers was completely open and the speakers were, of course, front-firing...."on, and off, the voice-coil more quickly"....this thread will accomplish nothing.....

 

[highfihoney]

ok here's my take on damping factors,i think its blown way out of proportion but i do think it counts to a point,mulester7 brought up a good amp to use as an example,the damping factor of a mc2200 is 16 according to roger russell(retired head of accoustic research at mcintosh labs),from my experience amps with very low damping factors like that will not produce the same results as amps with damping factors above 100.

amps such as the mc2200 that mulester7 is talking about is what prompted my question to gene in this thread.

 

[mulester7]

ok here's my take on damping factors,i think its blown way out of proportion but i do think it counts to a point,mulester7 brought up a good amp to use as an example,the damping factor of a mc2200 is 16 according to roger russell(retired head of accoustic research at mcintosh labs),from my experience amps with very low damping factors like that will not produce the same results as amps with damping factors above 100.

amps such as the mc2200 that mulester7 is talking about is what prompted my question to gene in this thread.

.....HiFiHoney, owner of about half the Mac equipment/amps on planet Earth, all the current new Mac amps list a damping factor of 100....did this change from years past?....and, I want you to understand, I was not cutting Mac amps, just reporting an AB experience......

 

[highfihoney]

.....HiFiHoney, owner of about half the Mac equipment/amps on planet Earth, all the current new Mac amps list a damping factor of 100....did this change from years past?....and, I want you to understand, I was not cutting Mac amps, just reporting an AB experience......

hello mulster & good morning,i understood your post & the amp you spoke of is an excellent example of how damping factors can & do play a roll in speaker response to a point.

mcintosh now makes solid state amps with damping factors of 100 & 200 depending on the model but in years past their amps had damping factors as low as 10 in some solid state amps,i think the low damping factors is the reason alot of people like to say that the older solid state mac amps sound very close to tube amps (weak bass response).

i do testing very similar to the tests you do but i use speaker a & b then switch back & forth between the two (no delay) & when i compared my mc300 against my mc252 using this method the mc252 had a much stronger bass response,both amps have the same specs except wattage & the mc300 has a factor of 30 while the mc252 has a factor of 100.

i also agree with gene on the figure's he gave being near the point where it begins to make very little difference but when amps have factors below 100 there are differences to be heard.

 

[mulester7]

hello mulster & good morning,i understood your post & the amp you spoke of is an excellent example of how damping factors can & do play a roll in speaker response to a point.

mcintosh now makes solid state amps with damping factors of 100 & 200 depending on the model but in years past their amps had damping factors as low as 10 in some solid state amps,i think the low damping factors is the reason alot of people like to say that the older solid state mac amps sound very close to tube amps (weak bass response).

i do testing very similar to the tests you do but i use speaker a & b then switch back & forth between the two (no delay) & when i compared my mc300 against my mc252 using this method the mc252 had a much stronger bass response,both amps have the same specs except wattage & the mc300 has a factor of 30 while the mc252 has a factor of 100.

i also agree with gene on the figure's he gave being near the point where it begins to make very little difference but when amps have factors below 100 there are differences to be heard.

.....ok, so we've established there is a difference in the sound quality according to damping factor, you say you only noticed a difference in the bass, I assure you I heard a marked difference full-range with "everything" being loooong, and Gene's opinion is that over 100 doesn't make a lot of difference, but I don't remember seeing it said there was "no" difference....what would you say the damping factor of the MC2105 I have stored along with the MC2200 is?.....I'll check for responses later, HiFi, and thank you for your input, you bees a good man, IMO....I will probably be called about noon to work, and I better go get some blissful snooze.....

 

[highfihoney]

.....ok, so we've established there is a difference in the sound quality according to damping factor, you say you only noticed a difference in the bass, I assure you I heard a marked difference full-range with "everything" being loooong, and Gene's opinion is that over 100 doesn't make a lot of difference, but I don't remember seeing it said there was "no" difference....what would you say the damping factor of the MC2105 I have stored along with the MC2200 is?.....I'll check for responses later, HiFi, and thank you for your input, you bees a good man, IMO....I will probably be called about noon to work, and I better go get some blissful snooze.....

the damping factor of a mc2105 is extremely low at 10,this does not mean that the 2105 is a bad amp infact some people seek out the 2105 & use its low damping to their advantage for speakers that they want to tone down the bass response in.

im not doubting that you heard other differences using the mc2200 through the full range but i did not,there could be many reasons that you heard substancial differences remember that were talking about high power amplifiers that are close to 40 years old,the mc2200 has a selectable input sensitivity that could have had a part in it by causing a mismatch with your preamp & with any vintage amp there could be many things that need to be serviced.

the amps that i mentioned doing a/b testing with were the mc300 & mc252 with both amps having the exact same specs except for wattage & the main difference i heard was loss of bass response in the mc300 while the mc252 had an iron grip on the bass.

im a firm believer that in alot of 2 channel rigs all amps do not sound or perform the same.

 

[rollinrocker]

HiFi

you are not alone in your beliefs.

 

[highfihoney]

Nothing will happen. If that DF was so important, there would have been an awful lot of positive outcome from DBT tests of amps over the years. There are no such data and the ones where there are audible differences, it was not the DF that caused the differences, but other issues.

I bet these two amps in this DBT, readily available on line, was even worse than what you posted:

http://groups.google.com/group/rec.audio.opinion/browse_frm/thread/664b8681ab141263/3fd91bcb6a1522a0?hl=en&lr=&ie=UTF-8&oe=UTF-8&rnum=1&prev=/groups?q=sunshine+stereo+yamaha+abx+nousaine&hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=501fl6%24ac3%40oxy.rust.net&rnum=1#3fd91bcb6a1522a0

ok were back to the dbt test again,the first thing i question about these tests is who the h#!! makes up the rules,give me a break,10 out of 10 is required for there to be a worthwile difference,complete nonsense

i can take 2 amplifiers made by the same manufacturer with all specs being the exact same except for damping,one amp at 30 & the other amp at 100,then match all levels as well as could be done in any lab,have both amps ran from the same source & into 1 set of speakers then do instantanious a/b tests with no interuption or time delay between switching & there are differences to be heard,i can also take both amps through various stages of exact wattage & where differences wont be heard at one level they can easily be heard at another level.

please explain to me how & why this method of instantainous a/b testing is flawed & not able to prove anything,if you do find this method flawed please explain in detail what the flaws are & why,preferably not with a google link

 

[PENG]

ok were back to the dbt test again,the first thing i question about these tests is who the h#!! makes up the rules,give me a break,10 out of 10 is required for there to be a worthwile difference,complete nonsense

i can take 2 amplifiers made by the same manufacturer with all specs being the exact same except for damping,one amp at 30 & the other amp at 100,then match all levels as well as could be done in any lab,have both amps ran from the same source & into 1 set of speakers then do instantanious a/b tests with no interuption or time delay between switching & there are differences to be heard,i can also take both amps through various stages of exact wattage & where differences wont be heard at one level they can easily be heard at another level.

please explain to me how & why this method of instantainous a/b testing is flawed & not able to prove anything,if you do find this method flawed please explain in detail what the flaws are & why,preferably not with a google link

I believe most modern amps above the price point of say, $2000, and the power point of 200WPC, would sound similar, i.e. hard for most (some can) people to tell the difference in DBT or just A/B with minimum time delay. I do, however, agree the way you compared your two Macs were not flawed at all. An amp with D.F. of 10 is just too low for anyone not to notice it's different sound characteristics than another one with D.F.=100.

 

[mtrycrafts]

ok were back to the dbt test again,the first thing i question about these tests is who the h#!! makes up the rules,give me a break,10 out of 10 is required for there to be a worthwile difference,complete nonsense

Not at all. Where did you get that number from. By stat tables at 95 % confidence and 10 trials, you need 9 correct responses. 15 out of 20 trials.

i can take 2 amplifiers made by the same manufacturer with all specs being the exact same except for damping,one amp at 30 & the other amp at 100,then match all levels as well as could be done in any lab,have both amps ran from the same source & into 1 set of speakers then do instantanious a/b tests with no interuption or time delay between switching & there are differences to be heard,

Level matching is only to .1dB spl, or 1% of voltage at the speaker terminals, not too hard.

As to audible differences, that has yet to be demonstrated. Actually, amps with different specs have been DBtd with no audible differences so DF is really a nothing issue when other parameters are more critical, yet sound the same.


i can also take both amps through various stages of exact wattage & where differences wont be heard at one level they can easily be heard at another level.

Only if there are design flaws that show specs above thresholds or some signals clip even though your controlled power at one point.

please explain to me how & why this method of instantainous a/b testing is flawed & not able to prove anything,if you do find this method flawed please explain in detail what the flaws are & why,preferably not with a google link

Why not a google link??? Who said instant a/b testing is flawed??? What the DBt shows is what one can really hear when bias is removed from listening.

If you are referring to your methods, you have other flaws: poor blind controls, who knows.
There are more than that one DBT in the link of DBTs of amps over the past 30+ years.

' The Great Debate: Is Anyone Winning?' Proceedings of the AES, 8th International Conference, 1990.

this has a compilation of 23 published tests, 13000+ trials

Masters, Ian G. 'Audiolab Test: Six Power Amplifiers,' Audio Scene Canada, May 1977, pg 44-50.

Masters, Ian G. ' Audiolab Test: Amplifiers and Speaker Cables,' Audio Scene Canada, Jun 1981, pg 24-27.

Masters, Ian G. 'Do All Amplifiers Sound the Same?' Stereo Review, Jan 1987, pg 78-84.

 

[mtrycrafts]

ok here's my take on damping factors,i think its blown way out of proportion but i do think it counts to a point,mulester7 brought up a good amp to use as an example,the damping factor of a mc2200 is 16 according to roger russell(retired head of accoustic research at mcintosh labs),from my experience amps with very low damping factors like that will not produce the same results as amps with damping factors above 100.

amps such as the mc2200 that mulester7 is talking about is what prompted my question to gene in this thread.

That output impedance may cause frequency response variations, not the DF. Bob Carver demonstrated this by adding a resistor in the output of his amps on some model.
But, if you can level match them out at a number of frequencies, you will not like the DBT results, guaranteed, no matter who protests however hard. It is a shame that some/many dismiss science. Probably the same folks dismiss evolution too and jump on homeopathic medicines, etc. This is not implying you, hifi.