What is amplifier damping factor?

[@wilcalint]

Paul did a commendable job explaining the "damping factor" in respect to tube amps. The effective resistance of the output transformer results in a low damping factor and less "control" of the speaker load. Speakers are electromagnetic devices. Effectively they are motor generators. When the amp delivers energy to the speaker it can expect to receive energy back ( cone overshoot and generating energy ) and it's ability to sink that energy will effect the sound. Amplifiers with high damping factors should effectively sink a lot of energy. I like to think of it as the big strong hand of the amp grabbing a hold of the speaker. I am the happy owner of a dual chambered subwoofer with a 16in Altec Lansing theater driver in it. A few years ago I married it to a bridged Crown XLS1000 amp that has a high damping factor ( >200 ), 8ohms, 10Hz -> 400Hz. I could clearly hear that the amplifier made a big improvement in the "control" of that big electromagnetic motor.

[@Pixeltrainer]

This explanation is clear as mud. :)

[@garywells9478]

A friend who worked as an audio salesman in the mid seventies brought an Accuphase power amp home to try out. On the front panel there was a 3 or 4 position switch that allowed the user to change the damping factor of the amp. The lowest setting, as I recall, was 60. I don't recall what the highest was, but nevertheless, the lower damping factor sounded better. Since then, I have always chosen amps with damping factors of no more than 100.

[@belaveszpremi1949]

I have Audia Flight FL3S italian amp with damping factor 26!!! but no way to replace it with Hegel or any other amp with trillion damping factor.

[@bargibargibargi]

Hey. This was my question! 😂

[@janinapalmer8368]

Damping factors .... YES !! One of my pet topics .... Paul is roughly right here here ... he didn't explain where the figure actually comes from though ... it's derived from the output source impedance divided into the speaker impedance . In tube amplifiers it's the same .. in the days of tube amplifiers ( pre solid state ) most speakers had an impedance of 15-16 Ohms .. this high impedance was to get a higher damping factor . It must be noted here that a loudspeaker system with a passive dividing network will have an impedance curve that is not 100% flat .. it will go up and down in value and hence the DF will vary too.

[@carolineleonard8214]

Janina Palmer I concur. It's great to know that the amplifier will have great control over the bass woofers though.

[@janinapalmer8368]

Paul Leonard .. in solid state amps the damping factor is a composition of several things .. one is the power supply ... the large storage caps must have VERY low ESR as well as the output devices must have low resistance and very high slew rate and equally fast decay

[@zulumax1]

What an interesting and unusual topic. Think of damping as an electronic shock absorber for your speakers. Bandwidth and frequency of damping is important, but mostly in the lower bass. An Adcom GFA-565 mono block has a damping factor of 1000. Early 70's transistor receivers have damping as low as 10, while my Heathkit W5M tube mono block amps have an unusually high damping factor of 40 which is high for a tube amp. Dynaco ST-70 has a damping factor of 11. Average is probably around 250 in my experience in modern transistor gear. Many factors effect damping, negative feedback, speaker wire, final output design, topography, and bias. 50Hz is common standard frequency used to measure damping factor. High damping factor good for subs, but can cause midrange to sound too sterile and lifeless in full range. Damping factor is the poor mans servo woofer in effect. These are my opinions of course, and am interested in what others experiences have been.

[@paulrs2975]

Yes, most of our experience says that high-end speakers sound better (mostly a wider, deeper soundstage) when driven by an amplifier with low to moderate damping factor, say 5-10. Bob Carver did have an interesting theory why this is the case. And yes, much depends on how good an amplifier's specs are BEFORE negative feedback is applied. Some, both tube and solid state, are good without feedback.

[@JohnAudioTech]

A typical speaker with a nominal 8 ohm impedance will have a DC resistance of around 6 ohms. This resistance is electrically in series with the amplifier and reactive part of the speaker essentially swamping the high damping factor of the amplifier. Even the speaker wire will swamp the high damping factor of the amplifier. If the speaker wire has a resistance of 0.2 ohms, it would reduce the effective damping factor to around 40.

[@poserwannabe1]

What are you running, 500' speaker leads ??

[@JohnAudioTech]

@@poserwannabe1 500' of 2 conductor wire, say 14 awg, is 1000' of conductor which would be 2.5 ohms. It doesn't take much length of wire to reach .2 ohms especially if using a thinner gauge.

[@poserwannabe1]

well yea but I'm assuming anyone at this level would be running 12 minimum ?? and normally no more than say 20' per side ?? nbd...

[@JohnAudioTech]

@@poserwannabe1 20' of 10 gauge (40' of conductor) DF would be around 200 if the amp had an infinite DF driving 8 ohms. That's very good. However, people seem not to understand or simply ignore the fact that the DCR of the speaker driver coil severely reduces the effectiveness of such a high DF from controlling the speaker.

[@johnyang799]

Cable must be considered as well. High damping factor will be masked by the impedance of cable.

[@IliyaOsnovikov]

Good point. I could hear better damping of my Energy RC-10s with 7 AWG cables instead of 11 AWG. The amp was Rotel RA-985 with a damping factor of 400 for 8 Ohm speakers. The RC-10s are more like 6 Ohm speakers and they have some slight boominess in the bass range.

[@Paulmcgowanpsaudio]

Yes, this is correct.

[@IliyaOsnovikov]

@IMMO ws Everything is more simple than you might think. If a bass driver has total Q factor (Qt) too high for a given enclosure, then bass output will be somewhat boomy. But the Qt is made of two other factors: mechanical - Qm and electrical - Qe. Qe also depends on the resistor values in a circuit from an amp output to the driver terminals. When one connects thicker cables with lower resistance the value of the bass driver's Qe also slightly drops. So does the Qt and the bass sounds cleaner with less boom.

[@bennyjorgensen]

And the restiance in coils in crossover. (And this is why i use DIY active speaker)

[@billwilliams6338]

why does the power amplifier output impedance cause the damping factor to increase or decrease? what else can cause the damping factor to increase and decrease?

[@ProDigit80]

The Eden WTX260 has a damping factor of 5000. I imagine it matters more to bass guitar amplifiers, than to mid or high frequency amps? The amp only goes down to 4 Ohms (I tested it at 3.33Ohms, but 2 ohms and it went into protection mode), but David's later amps ran 2 ohms just fine!

[@salvadorrodenas3071]

Very well unexplained, not always is the case Paul.

[@carolineleonard8214]

Have a listen to Hegel's H360 and H590. Damping factor in excess of 4000. They sound fantastic. I'd say reference quality , depending upon your preferred audio taste of course.

[@sudd3660]

Hegel states on H590: Damping factor: More than 4000 (main power output stage).. when BHK Labs Measurements came up with their number it peaked at 720 at 200hz, (Damping factor = output impedance divided into 8) www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1966:bhk-labs-measurements-hegel-music-systems-h590-integrated-amplifier-dac&catid=97:amplifier-measurements&Itemid=154 im not sure about how it actually works but we must be careful to measure it the same way or display it with same numbers to be able to compare. i downloaded my own power amp datasheet and got some numbers, or a curve to be more exact, a damping factor number only shows the peak value and that has to be put together with a frequency to make sense. my amp did not have a peak in the middle as hegel did, but a downward slope, in 8 ohm it was highest at 20hz at 8000 or so, and 900 at 1000hz.

[@johnyang799]

Higher than a number it doesn't really matter anymore. Because the cable is much higher impedance than the output impedance.

[@carolineleonard8214]

I understand. If the cable impedance is greater then, the question must be asked, what is a relevant and meaningful damping factor in an amplifier?

[@johnyang799]

@@carolineleonard8214 It's important to have output impedance lower than 1/10 of the cable. And that's why the cable matters. Also the open loop output impedance is important. The open loop output impedance is directly affecting the output current. General speaking nothing really matter if you can put out high power and makes the speakers output lower distortion.

[@gotham61]

The problem is that a high damping factor is often achieved by applying lots of negative feedback, and it is this which kills the sound.

[@johnyang799]

that's just the opposite

[@InsideOfMyOwnMind]

If you are using a speaker with an impedance curve that compliments the characteristics of the amp then true. But otherwise the matchup is a crapshoot at best.

[@carolineleonard8214]

gotham61 Please note that Hegel achieve excellent damping factor figures using feed forward designs. Check out their 590 model....... Truly reference for not a lot of wonga.

[@airgead5391]

@ Gotham: exactly! Furthermore, there will always be an series inductor in the X over to the bass speaker. Typical resistance 0.3 Ohm. So that would sets the maximum damping factor at about 27. Furthermore you can divide the speaker coil into a coil of 0 Ohm with a (think of it as external) series resistance of the DC value, let's say 3 Ohm. So.... damping factor is bogus factor.

[@hudo]

@@airgead5391 thanks for explanation. I have one concern at the moment with the whole damping factor thingy : i have Audio Analogue Puccini Anniversary, which has kinda low damping factor (27-40) probably because of the whole "no-feedback" design, and don't know how it will work with some "problematic" speakers: and i would like to buy Focal 1028be. AA has 80w into 8ohm and 150 into 4, so looks like enough power, but can low damping factor make it bad match for focals? Should AA me matched only with some easy driving speakers?

[@patrickalphenaar]

My XTZ Edge a2-300 PowerAmp has a >1500+ Damping Factor and you hear that so clearly in all frequencies! With its class D Technology and 150 Watts at 8 Ohm its my favorite Amp and is only 495 euro, meaning High-End doesnt always need to Expensive. Cheers.

[@royferntorp3575]

This answer has got me asking, how do you measure speaker impedance? Audio is AC but our multimeters measure in DC. Please explain.

[@gruffly78]

The basic explanation is that If you know the AC voltage, and can measure the AC current, you can calculate Z ('Z' being the symbol for impedance rather than 'R'). Z changes based on the frequency while R stays the same. It can get more complex but that's the basic premise.

[@royferntorp3575]

I'm always confused by this when using valve amps. They say 4, 8, or 16 ohms. I measure speaker impedance and mark the speaker. But it is always with a meter that measures DC. The speaker company rarely specs how they rate the impedance.

[@jonathansturm4163]

@@royferntorp3575 A speaker does not have a single impedance; impedance is resistance at a particular frequency and that resistance varies as the frequency of the signal varies. To add to the confusion, the impedance of the speaker is affected by cabinet design, and again this is frequency dependent. To add even more confusion. speaker manufacturers play pretty fast and loose with the specification of the impedance of their loudspeakers. The good news is mostly though it doesn't really matter. A speaker rated as 8 ohms will work just fine with an amp rated at X Watts into 8 ohms. Problems tend to occur with amps that are unhappy driving very low impedance speakers as they can become unstable. Best to consult the amplifier and speaker manufacturer if you contemplate such a combination. Hope that helps.

[@royferntorp3575]

@@jonathansturm4163 Assuming that speaker builders rate at un-loaded impedance....Output transformers really don't like some low resistance. And some are really expensive to replace. I believe Rola, JBL and Altec used to measure unloaded. I have had modern speakers rated at 5 or 6 ohm. WTF?

[@jonathansturm4163]

@@royferntorp3575 By and large speaker and amplifier manufacturers don't want you to blow their product up due to mismatching. They also don't want to frighten you with numbers that _appear_ threatening. This is where the "fast and loose" bit comes in. As I wrote above, when in doubt _consult the manufacturers_* and take the _numbers_ they provide with a judicious pinch of salt. Most of the time you're safe, but there's an occasional design that becomes "iconic" while it's also "difficult". * What I like about PS Audio is they are accessible, intelligible and honest. Edit: I know you want numbers, but speaker impedances are curves, not solitary numbers so any solitary number is already a kind of fiction. When different manufacturers measure/calculate that solitary number quoted in different ways, you also have an apples and oranges situation where comparison is essentially meaningless.

[@scottjohnson7774]

Enter in the now discontinued CROWN REFERENCE SERIES 1 Damping factor of 20,000 a beast of an amp ! Don't try to lift it by yourself

[@TheUnrevealer]

Naim amps, even higher range ones, also have relatively low damping factor, but they controll speakers well.

[@jonathansturm4163]

Back in the olden days when giants roamed the Earth and we wished speaker response curves were flat, solid state amps were the new kid on the block. They had one very great advantage over hollow state amps: much higher damping factor so the advertisements made a very great song and dance about this undoubted virtue. By the late 70s pretty much every solid state amp had a damping factor well in excess of what was needed. One amp might very well have a three or four times greater damping factor than another, but you would be hard put to it to hear any difference because of that. Bear in mind that these remarks apply to Class A, Class B and Class AB amps. Today there are Class D amps and damping factor _may_ be a consideration once more. If you listen to music with lots of very low frequency content, a Class D amp _might_ not be the best choice of amplifier, even though the reason you would consider Class D is for its high wattage and that's only needed for the lower frequencies with most speaker designs.

[@CraigFlowersMusic]

So the Carver M-1.0t has a damping factor of about 8, and says "Low Feedback High Gain" on the faceplate. I didn't know these were related. Why then does IT sound so relatively good with such a low damping factor?! Tube amplifiers have high impedance. I have a Sunfire which has two different kinds of outputs; one of which is around 1 ohm impedance to, apparently, mimic a valve amp. This all flies in the face of convention, so why is that?

[@alext2933]

Great news Paul as my new Hegel 190 has a damping factor of over 4000. You say 1000 is great so impressed with my new amp's specs.

[@alb.1911]

I never see this value in any amplifier... I can just remember the values of 1000 or 1500 in some Krell, Mark Levinson and Parasound JC1. Thanks for the info, I will check this model...

[@alext2933]

@@alb.1911 Glad to help. Their Soundengine2 amp tech is unique to them I am told. Super powerful too. I tried the Hegel 360 (250w at 8 ohms, 420w at 4) but realised the newer 190 (150w at 8, 250w at 4) was enough for me. Both have damping factor of over 4000. Go listen.

[@andreasmoller9798]

@@alext2933 h190 is a masterpiece own one my self

[@ΓΙΑΝΝΗΣΚΟΥΚ-ε6δ]

@@alb.1911 also the rotel Ra 980bx has the same damping factor 1000 Old amplifier but strong enough..

[@419gcs]

Damn that was my question to Paul

[@Cartier_specialist]

My NAD has a damping factor of 110. I'm guessing that's pretty darned good because it has enormous headroom according to the spec sheet but fortunately I don't listen to spec sheets I listen with my ears.

[@Gez492]

The true measure of an amplifier in combination with a speaker is how it sounds, that's why I like tube amplifiers be they Pre Amps or Power Amps. I never get too hung up of spec's. I listen to speaker amplifier combinations with different types of music Iike and decide what sounds best to me. Damping factors are pretty much meaningless after a point. There are certain scenarios where the damping factor becomes less meaningful: Tube amplifiers typically have output transformers that provide impedance matching between the amplifier and the speakers. The output transformer's primary winding and secondary winding ratio, along with the speaker impedance, determine the damping factor of a tube amplifier. The damping factor of tube amplifiers is generally lower compared to solid-state amplifiers. While solid-state amplifiers can often achieve damping factors in the range of 100 or higher, tube amplifiers typically have damping factors ranging from 5 to 30. The lower damping factor of tube amplifiers is not necessarily a limitation or a drawback. Some argue that the slightly reduced damping factor can contribute to the "tube sound" characteristics, including harmonic distortion and a smoother, more musical presentation. Many tube amplifier enthusiasts find the lower damping factor to be an inherent part of the amplifier's overall sonic signature and appeal. It's worth mentioning that the perceived importance of damping factor can vary among individuals and is also influenced by the loudspeaker characteristics, and listening preferences For instance in Active speaker systems each driver i.e woofer, midrange & tweeter is driven by its own dedicated amplifier. Since each amplifier is directly connected to its respective driver, damping factor becomes less significant. The output impedance of the amplifier is not interacting with the speaker's impedance, as the internal amplifiers are typically designed with low output impedance so the damping factor is not a critical factor to consider in active speaker systems I think its true to say most modern speakers are high-efficiency; speakers with high sensitivity and efficiency require less power to produce adequate volume levels and typically exhibit a relatively flat impedance curve and an easier load to the amplifier. Damping factor may be of less concern than early solid state and Tube designs, as the speaker's impedance variations have less impact on the overall sound quality. Damping factor may be less meaningful in these scenarios, there are other important factors to consider when selecting an amplifier, such as power output, signal-to-noise ratio, distortion levels, and overall sonic compatibility with the speakers synergies if you like. Stupid high Damping factors do not guarantee a good sound quality just in the same way High Damping factors wont necessarily sound drier or more neutral. My advice listen to as many as you can within your price range and pay attention to system matching not pages of spec's.

[@42ssh]

For solid state amplifiers, damping factor does not mean anything in practice. You really do not have a damping problem with a solid state amplifier anymore. With high output impedance tube amps, you need to consider the damping factor with the matching loudspeakers.

[@janinapalmer8368]

bsb With valve amps you can achieve a good damping factor by using the thickest gauge wire possible for the speaker secondary winding and a speaker with 15 or 16 ohm impedance.

[@jonathansturm4163]

An engineer who isn't very good at mathematics? You have my sympathy; my brother got all dad's mathematical genes... Worth noting that Class D also struggles a bit regarding damping factor, not just hollow state.

[@cbcdesign001]

I am in the same camp. I know the formulas I need in my everyday calculations for the circuits I produce (resistor dissipation for example) but anything new and I have to look it up.

[@airgead5391]

Paul, please read my comment elsewhere where I explain that the damping factor is the bogus factor. I am curious about your thoughts about my explanation.

[@Paulmcgowanpsaudio]

Not sure where to find your comment but damping factor is hardly bogus. Much depends on what type of speaker you're asking the power amplifier to control.

[@homeboi808]

Paul, Damping Factor is indeed not bogus, Dr Toole made a 2-page article many years ago that’s available online. However, the damping factor of any modern solid state amp is good enough, the damping factor from your speaker wire (based on gauge, no matter if they are lamp cord or $20,000) has a much higher impact, like magnitudes more. For most setups, 16awg will be good enough, and 14awg if it’s a long run. For your S300 amps, if running 2ohm minimum speakers, and wanting a system DF of >20 (what Toole and other claim is the audibility threshold), and if you need 30ft runs of speaker wire (say using an AV closet), you thus would need ~14.9awg, and since that doesn’t exist, use 14awg.

[@airgead5391]

@@Paulmcgowanpsaudio , thank you! A copy paste from a reaction to gotham61: Furthermore, there will always be an series inductor in the X over to the bass speaker. Typical resistance 0.3 Ohm. So that would set the maximum damping factor at about 27. Furthermore you can divide the speaker coil into a coil of 0 Ohm with a (think of it as external) series resistance of the DC value, let's say 3 Ohm. So.... damping factor is bogus factor.

[@Paulmcgowanpsaudio]

@@airgead5391 Except damping factor has nothing to do with the speaker. It's calculated by the output impedance of the amp. Or, perhaps I misunderstand what you're saying.

[@airgead5391]

@@homeboi808. I found the article and it exactly confirms what I was saying: so I think you made a mistake by saying that damping factor is not bogus because it is.

[@chipsnmydip]

What would you define as a high damping factor?

[@homeboi808]

More than 100 is good enough for amps. The gauge of your speaker wire actually has a vastly larger impact, pairing a 1000 DF amp with 22awg wire will be worse than a 100 DF amp and 16awg. The Emotiva PA-1 monoblocks (Same amp in the PS Audio S300), has an output impedance of 0.005ohm (DF >500 for 4ohm and min load of 2.5ohm), and 10ft of 22awg has a resistance of 0.161ohm, and if you had 4ohm speakers, that’s a system DF of 24. 10ft of 16awg has a resistance of 0.04ohm, that’s >40x smaller, which is better, the system DF would then be >85.

[@jonathansturm4163]

About six inches (150 mm) of rainfall. Our water tank is nearly empty and I'm beginning to get a bit smelly. It was supposed to rain last night, but it's now mid-morning and the sun is still shining.

[@SteveKasian]

@@jonathansturm4163 LOL!!! Sounds like you've got a fairly low damping factor right now. Good luck with that!

[@jonathansturm4163]

@@SteveKasian It's quite dry again, but this year the tank is full.

[@BlankBrain]

JohnAudioTech demonstrates damping factor in this ~24 minute video. kzbin.info/www/bejne/d3vQdZacipuBobc It really surprised me how _unimportant_ damping factor is; you need some, but not a lot. Damping factor is a good indicator of how much negative feedback is used in the amplifier. It has little to do with how well the speaker is "controlled."

[@manjulwalia1995]

Please remake the video with better explanation ...

[@Yiannis2112]

Manjul Walia The explanation was fine. If you feel you're not covered, a bit of reading won't hurt you. Dozens of pdf articles on the matter.

[@jamescorbell3349]

Stick with amps that have a fairly high damping factor🤔🤔, damn now a have to throw away all my made in 1970's Marantz amps.

[@stephenwong9723]

It’s not a good episode, sorry. You’ve to explain the meaning of amplifier controlling the driver and (you don’t want) not vice versa. Or, you just throw some misery term out but nothing in substance. A bit disappointed.

[@stephenwong9723]

@Larry Niles I didn't understand the explanation, that's factual. I said what I feel after seeing this episode, if only positive comment is allowed here, I'll shut up and quit.

[@poserwannabe1]

an amplifiers damping factor is the ratio between the number of desiccants packs supplied in the box divided into the wattage.... 400w/4packs=100df simple.. this keeps the amp from getting "damp"..

[@bryanp4827]

Damping factor is the amount of water your amp can hold, anyone knows that!😂🤣😜🤣😂😜😂🤣😜🤣😂😜🤣🤣😜

[@hometheaterfever5]

Ahhh Ok. Soooo what’s a damping factor? 🫣