One of the seminars I used to give on loudspeakers and amps included demoing Damping Factor. Very easy to do. Take any speaker, the larger the woofer the better, with it disconnected from any amp, tap on the woofer cone and listen to the resonance. Then short the speaker terminals, a piece of wire, I would use my keys, and tap on the woofer. The amount of control exerted on the woofer by itself, the counter EMF allowed to flow in the completed circuit, is extremely audible. To then explain how a high damping factor means low internal resistance in the amp, like the keys shorting the terminals. And how that allows a speaker to control it's own excessive reaction to a signal.
@@BubblePuppy. Yes, a wire moving through a magnetic field generates a voltage. It is in the reverse direction (polarity) to the voltage sent by the amp. It is called Counter EMF (Electro Motive Force). Damping Factor is the mathematical ratio of the speaker impedance to the amplifiers output. A perfect solidstate amp would have a zero ohm output stage. It would act like the keys and allow the counter EMF to feed back and control itself. With no load on the speaker you are hearing basic resonance of the driver/ cabinet. With a short you are hearing how a good amp takes control of that speaker system.
Hi Paul. Thank you for your patient knowledge and experience sharing. Great Videos. Regarding an output of an amplifier impedance, In my experience and knowledge, it should be lower such that it's presence will not be a noticeable. The actual damping impedance for the driver of the speaker is the sum of: a. Amplifier output impedance b. Amplifier Binding Posts (Both Plus and Minus) to speaker wires resistance ( Let's assume 0.05 Ohm) c. Speaker cable impedance (Both Positive and Negative, lets assume 0.1 Ohm for 2 meters cable) d. Speaker Cabinet Binding Post (Both) (Let's Assume 0.05 Ohms) e. (In some Cheap Speakers) Speaker internal wiring ( lets assume 0 Ohm) f. Cross Over Coils internal DC resistance (lets assume 0.2 Ohm) g, Speaker Driver internal DC Resistance (usually few ohms, but let's assume 0 Ohms) i. For the Woofer: Serial Coil impedance at Pass Area, i.e if upper 3dB cut frequency for the woofer is 1000Hz (for 2 order C.O), it means that coil impedance at 1000Hz is ~ 4 ohms, it means that at 100Hz Coil impedance = 0.4 ohms and 0.1Ohm at 25Hz So by this example we see between the amplifier and the speaker added resistance /impedance of ~0.8 Ohm @ 100Hz If my example is close to real life, it means that an output impedance of 0.08 Ohms = Damping factor of 100 is more then enough for an amplifier. As per Feedback, too much feedback kills the Power amp slew rate (Rise time) ability. A high Slew rate is a parameter not so known or looked at, but IMHO very important indicator for the amplifier bandwidth, speaker synergy behavior and clarity. Thanks and best regards
Thank you Paul. I really appreciate these videos and the time you spend to make them. Best on TH-cam by far. Have lived in evergreen Golden Denver Lakewood Aurora Littleton and conifer. I live in fort Worth Texas at the moment but someday I'll make it back.
In my old car stereo days, everyone knew Fosgate Punch and the new-comer HiFonics amps had big damping factor for that big bass hit. Then outboard caps came along with crazy subs like Sundown (sp?), which really gave the hobbyist who likes bass, something really nutty. This is a great series; picking a speaker with high impedance can drastically lower the damping factor of an amp, so knowing speaker impedance and amp output is important, especially when it comes to low sensitivity speakers that hover around the mid 80’s dB per watt sensitivity and pairing that up with say a low output tube triode mode amp that say makes 10 and less watts per channel. Keep up the good work.
"picking a speaker with high impedance can drastically lower the damping factor of an amp" The damping Factor of an amp is a set measurable number. Basically it is the amps' "output impedance". It does not change based on what it is connected to any more than it's input impedance. You could go from a 2 ohm load to a 2M ohm load and the amp's output impedance would stay the same. And it would not change what number is published for an amp's Damping Factor as that is just the ratio of that output impedance into an 8 ohn load.
@Douglas Blake I guess I just don't get the fascination with forcing "Damping Factor" into usage it has no place in. DF is simply one spec to help evaluate an amp on paper. An indirect way to publish an amp's output impedance using bigger nontechnical numbers. "Damping Factor: 100" looks much better on a spec sheet than "Output impedance: 0.08 ohms". If one pretended DF to be of value in an actual installation with typical speakers (maybe 6 ohms - 30 ohms 20-20Khz) the system spec for an amp with a published DF of 10 would show "DF: 7.5 - 37.5, 20 - 20Khz.". This additional, strictly mathematical process does not provide any new insighs.
@Douglas Blake two issues. Both involve trying to twist a simple indirect published specification into something it is not. Basically A/B=C. For DF: A = amp output impedance, B = 8 ohms, C = DF. Yes you could continue to use the formula A/B=C with A = amp output impedance, B = (some external value, instantaneous speaker impedance at given freq, total wire/ speaker @ freq) with the resultant C = some number that will then be called "Damping factor". But other than using the non-changing Amp output impedance, the results has nothing to do with what the term "Damping Factor" as published in an amp's specs means. You could just as easily use A/B=C with A = 1550 ohms (Shure M97), B= 47K ohms (preamp input) and claim that circuit has a Damping Factor of 0.033. It comes down to trying to use the term "Damping Factor" where it was never intended to apply. It is nothing other than a way of spec'ing an amp's output impedance. Next that a DF of 10 is sufficient. Again, sticking to the actual definition of "Damping Factor" as the published output impedance based on an 8 ohm load, that would mean a 0.8 ohm output impedance. The same results as adding 400 feet of 12 ga lamp cord to an amp with a 1,000 DF when driving an 8 ohm load. I would not find that acceptable.
@Douglas Blake You are correct that I started out by correctly explaining that "Damping Factor" is a number published as a spec by amp manufacturers determined by dividing the output impedance of that specific amp by the number 8 to represent an 8 ohm non-inductive load. that number as published has nothing to do with how that amp might be used in the future, what it might be connected to, how many feet of cable, what brand speaker, the speaker's constantly changing impedance, humidity nor latitude. Just as the published S/N of an amp has nothing to do with the room it is later put in and the room's noise floor. It is just as irrelevant to claim an amp with a published S/N of 110db has a S/N of 70db because of room noise. This has been true since I received my degree in electronics, got an FCC Broadcast license, spent the 1st 10 years of my giving lectures and clinics in Audio for some of the top manufacturers, (Marantz, AR, AT, Kenwood, Maxell, Pioneer Auto, ...) over 50 years ago. Including running a regional Kewood repair facility. To then move to Broadcast Video including entire TV video facilities and satellite uplink vehicles. and then to CGI selling the systems Jurassic Park and Terminator came out of. Not to mention my dedicated 56k link to ARPANet, now called the Internet. Wrapping up with leading edge IT products shipped around the world. so with the facts solidly behind me, I will not be changing my mind soon.
Super job by Paul on this one. One way to better understand this is to connect an analog voltmeter across a cone speaker terminals and measure the changing voltage as you gently push the cone in and let it come out. The voltmeter will register the changing voltage. The amplifier has to control/sink that generated voltage/current. Also "Damping Factor" is frequency dependent. An amplifiers damping factor will be different at 60Hz than it is a 10Khz.
A very effective demo is to tap the woofer on a disconnected speaker. (larger the better) then short the speaker terminals and tap again. The difference is extremely audible and a direct demo of what damping factor does.
@@wilcalint Yes that is exactly the Counter EMF, the voltage generated by wires moving in a magnetic field, that needs to be shorted out, needs to be allowed to control the driver instead. And that is what the DF number tells you. How close to a dead short is the output of the amp so this Counter EMF can be controlled. The number is just a ratio between the amp's output impedance and an 8ohm load. A DF of 100 just means 8ohms/100 = 0.08 ohm output impedance. another way to look at this is 12ga zip cord is 0.02 per 10ft. So an amp with a DF of 100 is like adding 40ft of lamp cord.
Great topic. I find these posts interesting in themselves. Often it prompts me to read further to understand the topic at a deeper level that possible in these brief videos. In this case I spent an hour reading AudioReality which covers this very well in layman's terms.
I love my Hegel Norway H80. It's just a baby at 75Wpc. But has 1000+ dampening factor. All is Full of Love by Bjork can sound absolutely terrible on a lot of sub $4000 integrated amplifier's but this guy at $2000 when new in 2014 was Holy moly WOW. Absolutely no listening fatigue yet still sounds commanding/powerful!
My Bryston 3bst has a very high damping factor. It takes total control of the speaker; sound is very quick and tight. So its quite common to pair a tube preamp with them to tame them.
My own anecdotal experience gained over a course of 45 years of owning one amp or another is that damping has a sweet spot, and that amps with very high damping factors just don’t sound very good. I doubt that anything over 200 or so is actually beneficial especially with speakers that have over damped low ends to begin with.
You're not alone, and not the first... See the two articles from 1954 and 1955 (!!) by D.J. Tomcik: Missing Link in Speaker Operation, Parts 1 & 2: - The Amplifier Damping Factor and its Application to Speaker Performance - Obtaining Variable Damping Factors in Amplifiers; Determining Critical Damping Factors And, on top of all that, the actual electric damping is heavily modulated by a continuously changing voice coil resistance.
Having Paul comment/answer all these questions, i do learn alot. OTOH, reading the comments sections, one can also learn in depth what was asked....But am still lost here :-)
Don't overcomplicate it. Damping factor simply relates to the output impedance of the amplifier in relation to the speaker. A speaker is a kind of motor; and, like many motors it becomes a generator when used backward. As a speaker moves it generates momentum and tends not to want to stop. Then it acts like a spring and wants to snap back -- overshooting equilibrium and causing an unwanted resonance. You can hear this as ringing in your system. While the speaker is resonating, it is actually generating electricity since the speaker coil is resonating in the magnetic field of the magnet. So the amplifier can prevent the "ringing" by sinking the electricity that the speaker resonance is generating. However, impedance between the coil and the amplifier will slow this process down and inhibit the ability of the amplifier to absorb the ringing in a timely manner.
@@timharig Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
The resultant listener experience with damping factor is in speaker cone control, and that means distortion, since the most distortion is introduced in the speakers. Big speaker cones at large volume with low frequencies are not easily controlled.
So many interesting things here. But one nobody bothers to ask and it was how high is Paul’s damping factor?? hehehe it was ALMOST a joke Paul! Great stuff keep it coming. 👍👍
Damping Factor is only one of many factors that affecting the damping ratio denoted by ζ (zeta) of a speaker system. To achive best speaker sound, the damping ratio must be tuned to a proper value depending on the design of the speaker system. For any speaker system, there must be a best matching amplifier outpout impedance. In old days when speakers were designed for high output impedance vacuum tube amplifiers, damping of speakers were mainly done by mechanical means. Nowadays speaker dampings are partly mechanical and partly electrical since solid state amplifiers have low output impedence. So, whether high damping factor is good or not depends on what speaker to be used. Furthermore since amplifier output impedance is connected in series with speakers, as long as speaker impedance plus cable impedance dominates the total series impedance say 99%, further reduction of amplyfier output impedanc makes no noticeable differences. Therefore a damping factor of 100 is high enough. Increasing damping factor above 100 has negligible effect.
Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
Rather than passive damping, you can have active damping with servo feedback. This is especially possible for a subwoofer but much harder to engineer for superior performance.
You are 100% wrong here. The servo doesn't do ANY damping, it does correction on cone overshoot. It can, by the way be done full range. Philips did that with "Motional feedback" as they call it very long time ago already. So damping factor of an amp and a serve controlling a box speaker are 2 totally different things. If the damping factor of the amp is not good enough, your input to the speaker is distorted. Nothing any servo can do to correct that. Maybe ask Paul.
@@ESL-Plus Damping is about reducing resonant ring of the cone. The damping factor is about how effectively the amplifier can short the voice coil to cause an electromagnetic brake of the motion. Ideally the amplifier is having zero Ohms output impedance for maximum damping. Active damping means your amplifier is actively damping the resonant ring by applying an opposite signal to the ring for even more effective damping than zero Ohms. A servo subwoofer (e.g. my Velodyne sub) is using such principle and Philips introduced it decades ago.
@@ThinkingBetter Paul mentioned in his video (and that is a fact), that the amps output changes because of the reactance (3 factors: impedance, inductance and capacitance) of the speaker. Your servo doesn't change the speakers reactance (combination of multiple coils and a cross-over) to the amp, it only acts as a mechanical correction. Sorry
@@ESL-Plus First, impedance includes resistance, inductance and capacitance. Reactance is just the non resistive part of impedance. Damping factor is the ratio between the loudspeaker impedance and the total impedance driving it. An amplifier with high damping factor has low output impedance causing a more effective short circuit of the voice coil against unwanted resonant oscillation. A servo feedback goes a step further in damping the voice coil motion actively by applying an opposite phase signal (feedback loop) during the resonant ringing further damping it.
people over think the output Z too much when it comes to headphone systems. Most headphones aren't sensitive to impedance matching with the amp. IMHO, low output Z on the amp doesn't mean it will sound best. e.g. a tube amp has higher output Z and it sounds more "natural" than solid state with under 1 Ohm output Z. I would say for headphone amps, 5-15 Ohms output Z is good middle point.
Yeah, a DF of 4000 is just a 4 ohm speaker driven by an amp output impedance of 0.001 ohms, which is about the minimum output impedance you'd really realistically want in an audio power amp for good, full sound. On the high end you don't want much above 0.01 ohms of audio amp output impedance, like Paul said, and that amount which when driving a 4 ohm load, would then be a DF of 400. I've seen amps (and receivers) with DF of between just below 100, (like 80 or so), and a few thousand, like those Hegel amps you mention. Anywhere in that range is good DF for an audio amp, but you just don't want anything much above (or below) that range because it will start to reach that point of sound degradation, as Paul mentioned here.
@@JoeJ-8282 Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
Hegel has high damping factor, thats not the reason i bought it, i like them as pakage, they have very good controll and good details in the sound without being bright
The you don't understand what Damping Factor is. DF helps show how well an amp is able to control (damp) a speaker so it can "have very good controll and good details in the sound". A high damping factor can mean the amp can better control the speakers' movement. Force it to do what it wants.
I get intermittent pauses in audio only while streaming and only in surround sound. If I turn off surround and just use the TV speaker it is eliminated. Using all HDMI or ARC cables. System Sony TV XBR 75X900H Receiver Yamaha RX-V685 FIOS fiberoptic box Sony BluRay Paradigm 6 speakers including the subwoofer Any ideas on a solution or who I can ask on what to do? TY
8ohm speaker divided by .01 is 800 which is a very high damping factor for a power amp. Did you mean 8ohms divided by .1 which would be a damping factor of 80?
It's determined by the circuit. In an emitter-follower topology the transistor has fair amount to say about it; but, so do things like the power supply that is supplying the transistor.
Every output can be defined as a Thévenin equivalent source with an idea voltage source in series with an impedance: en.m.wikipedia.org/wiki/Th%C3%A9venin's_theorem It isn't necessarily a single component that creates the impedance. It is a result of the entire circuit topology and everything in it.
@Douglas Blake Manufacturers almost always (unless stated otherwise) use 8ohms as the load to calculate their DF. And often only at one freq (400hz sinewave?) Which adds confusion to the whole discussion. Few "8 ohm" speakers stay anywhere near 8 ohms across most of the freq range. Some going up to 30 ohms or higher and my Maggies down to 2ohms above 2k. And amps can change output impedance at different frequencies as well. An amp with a DF of 10 would mean 0.8ohm output impedance. Even if they measured 20-20khz my 2ohm @ 2Khz would mean my DF would be 2/.8 = 2.5. Now, 10ft of 12ga wire is roughly 0.04ohms. We spend a fortune on better wires to drop that even the slightest bit lower? But accept adding 0.8ohms on top of it? So no a stated DF of 10 is not good enough. While yes there is a point of diminishing return, it should be at least 100. That at least means only twice as bad as zip cord.
I have a vintage amp with newer speakers, I think that's the way to go. The speakers are super analytical/revealing (too clean) but the old class A amp gives it some warmth and nice distortion.
@Douglas Blake No I did not miss that. Again a DF is measured into 8ohms. That is what that number is. A DF of 10 mans the amp has a 0.8 ohm impedance. That impedance does not change as the speaker load changes. If you go to a 4ohm speak that same amp will have a DF for that speaker at it's 4ohm spot of 5. Thus not even meeting your 10 requirement and it is the same amp. And again, a DF of 10 (@8ohms) is equivalent to 200 ft of 12 ga zip cord. And you consider that acceptable? And once more, most amps only list the DF at one frequency when it changes across the audio spectrum. So even that DF 10 will be well below that at other frequencies. As Paul says, 100 minimum. And across 20-20Khz.
Zero feedback single-ended triode (SET) tube amps tend to have a very low damping factor - around 2 to 10 depending on the size of the output transformer. Push pull tube amps with feedback have higher damping factor. Typical solid state class AB designs have a damping factor over 100. From a design standpoint, some engineers consider the output filters of a typical modern class D power amp will lower its damping factor when compared to a direct coupled class AB solid state amp.
@Douglas Blake An inductor that has an impedance of 0.001 ohms from 20 Hz to 20 KHz then having a gradual rising impedance starting at about 8 ohms at 60 KHz? 🤔
@@laurentzduba1298 Exact formula for inductor impedance is RL(f)=2*𝝅*f*L, where f - frequency, L - inductance in Henry (after Joseph Henry), while symbol L is after Heinrich Lenz.
the impedance of an inductor based on the value of the inductance, L, of the inductor and the frequency, f, of the signal passing through the inductor, according to the formula, XL= 2πfL.
I have pma 2000 ivr Yes it drive my b&w 801 s3 no more then 9.00 or 10.00 oclook I to high vol teromnsos bass open clere mis ..superb clerty on highs as you see the music This is my 3th denon From 1988 i haed pma 6600 / pma 1060 This one is what i need for 801 ... Best refards You well see it in my chhanal IL
Damping factor ...... oh boy !! Firstly an amplifier output should be non reactive so it won't have impedance ... only resistive ! Secondly if you are familiar with typical speaker impedance curves you will notice the peak in impedance at the resonance where the impedance figure can rise much more than the nominal impedance.. here the damping factor can be very much higher.
Outputs are only non-reactive if direct coupled solidstate. Tubes (most) use transformers which have high inductive reactance. Some SS amps use DC blocking on the output. Most include a small I/C or R/C circuit in their outputs to stop "speaker cable resonance". And today's digital or Class D? But yes the closer to purely resistive the better. But this again confuses what "Damping Factor" actually is. It ia nothing more than a number for the ratio between the amp's output impedance and 8ohms. How the number is determined has nothing to do with eventual usage. e.g. a 100DF @ 8ohms is a 0.08ohm output impedance. changes in the load do not change that value. Nor do they change how a manufacturer publishes a DF @ 8 ohms number.
@@glenncurry3041 the DF is the source ( amplifier) impedance divided into the QUOTED speaker impedance. But in the real world we know this is not the case ... the DF will vary according to the overall shape of the speaker impedance curve 😃
Everything in system design is a compromise and obsessing on damping factor as the bad boy is not helpful. Improving the damping factor can cause other issues in amplifier design especially when it comes to negative feedback. Also some speakers can sound less sterile when using an amplifier with a poorer damping factor.
My Bryston B60P at 4 ohms is What I listen to my records and music on V.s when I listen to my kitchen syestem is a little cheap class d FEEDBACK is definitely something better built amps take care of very nicely
@@johnsweda2999 I believe he means double conversion ups. Also called online, since the DC/AC inverter is always connected on. As opposed to the other two types of ups, the offline/stand by and the line interactive architecture.
Dampingfactor of 100 and more is theory, cause in line with the Speaker are the Cable, Connectors and if passiv the crossoverparts. Only way to have the benefit from a high dampingfactor is an activ speaker system. A passiv System not higher than 8 for an 8 ohm System, or 4 for a 4 Ohm system
A manufacturer measures and publishes Damping Factor as measured into an 8 ohm load. That published spec has nothing to do with external wiring, speakers or crossovers. It is a completely meaningless and useless number other than a way to get the output impedance of the amp. Chosen because the numbers look better than the technical equivalent.
@@glenncurry3041 yes right, the number is meaningless, a other description for a output impedance. for the whole thing you must also add the the impedance ,all parts between the amp and the speaker. A assumption from 1 ohm for the parts is real. The speaker(the generator) sees a load from 1 ohm and the output impedance from the amp. For the speaker it is no difference if it is 1ohm (parts) and 0,01 ohm (amp) or 1 ohm and 0,1 ohm. A activ system can minimize the parts impedance, short soldered cables, no crossover, no connectors
@@cbts001a4 Make sure you first give any wire connections a solid crimp before soldering. Crimping is actually a better lower resistance connection than soldering. Solder has 5-7 times the rsitance of copper.
The coils and wires may add up to a half Ohm maybe, then factor in an additional 6 Ohms of series resistance within the 8 Ohms driver. So the system damping factor can never get better than 1.33. So forget 100, 800 or 4000 damping factor. You still end up at 1.33
You can also look up the ingredients to a Boston Crème Pie, and buy one online, but making it from a recipe is much more gratifying. I like Paul's explanations.
Depends on the speakers you got high efficiency speakers at 98-99 DB then really you want a low damping factor 60 to 120 damping factor up to 300 is fine you don't need to go any higher than that. Only caveat is if you're playing subwoofers bass reflex then maybe up to 600
Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
Just give us the output impedance of the amplifier, the DF number is just a construct. The idea that the amplifier can add damping is a mathematical myth since you would need a negative impedance to improve amplifier damping and a positive number can only make the damping worse. The T-S equation that defines (2Pi*Fs*MMs*Re)/(BL)^2 where Re is always a positive number that must be the _added_ value in Ohm of the output impedance of the amplifier _plus_ the impedance of the speaker. Note there is no partial division of Re parts of the impedance of the speaker versus the output impedence. They cannot be divided, they must be _added._ But I am sure that even those solid numbers will stop the DF myth. Also, T-S tells us in no uncertain terms that the damping of the loudspeaker *_is entirely defined by the alignment._* So the output impedance is only a part of what can _modify_ the alignment. But if you equalise the current of the amplifier, so that all frequencies below 200 Hertz the current is the same (flat impedance), this will in effect cancel out the output impedance of the amplifier in the sense that the amplifier output impedance cannot change the alignment. This is not theory, it is a fact, both mathematically correct, and that there are now several DIY loudspeaker designs that do this - *_the output impedance of the amplifier can no longer influence the alignment._*
Yes, and no. It takes a lot of instantaneous current to move something that is purely capacitive. If you only fed it voltage and almost no current, the capacitance of the panel would act as a low pass filter. Lower output impedance (at the same high voltage) would have better control. Same goes for electrostatic headphones, the Stax SR-007 being famously harder to drive, due to higher capacitance. Thankfully many electrostatic speakers have amps built in. If it uses transformers, that damping factor still applies as it multiplies the effective capacitance seen by the amp. Most amps at that voltage already have enough current, even transformerless tube.
Damping factor is pointless without demonstrating stability on phase changes. German audio magazines test amps. by showing damping as function of phase change or stability. But then .. only in Germany they understand how to build good amplifiers ....
You don’t need electromagnetic damping and you don’t want electromagnetic damping. Of all the ways of damping electromagnetic damping is by far the worst. And why is it bad? * It is unpredictable. A lot of factors have their influence on electromagnetic damping: Amplifier output impedance, cable impedances, voice coil impedance, voice coil temperature (and thus room temperature and how loud you play). So, you have no control over the amount of electromagnetic damping. So, you have no control over what the driver is doing. * Electromagnetic damping is making use of the driver as a generator, as a microphone. It doesn’t only pick up the cone resonance, it picks up all cone movements: external sounds, sounds inside the enclosure, cone vibrations, added harmonics, port noise, noise from ferro-fluids, noise from eddy currents, etc. The generated signals distorts the input signal, the lower the output impedance (the higher the damping factor) the more distortion. * For electromagnetic damping you need a low output impedance (a high damping factor), which makes the current and thus the output of the driver sensitive not only to back-emf (“the microphone signal”), but also to the voice coil inductance and the voice coil resistance. * The inductance is not constant, it is modulated by excursion and by current. As every ferromagnetic filled coil this creates phase shifts, modulated noise, distortion and especially (added) intermodulation distortion (till 30%, see the website of Klippel for more information). * The resistance is not constant. It is modulated by temperature, and thus also modulated by the music itself. Changes in voice coil temperature changes the output (thermal compression), changes the electromagnetic damping and changes the frequency response. The thermal compression is driver impedance dependent and thus frequency dependent. * And above all, electrodynamic drivers are driven by current (201 years ago, already, Ørsted found that it is the current and not the voltage that creates the magnetic field and thus the force). So, when having a low output impedance (which makes the amplifier a voltage source) you give the opportunity to have all kinds of impedances and voltages (EMF) their influence (compression, distortion and modulated noise). There is also another form of electromagnetic damping. The movement of the voice coil generates eddy currents in conducting voice coil formers, which create modulated noise. And that is picked up by the microphone effect and added to the input signal. To get rid of all these effects you need two things: a high output impedance, 800 Ω or more, and non-conducting voice coil formers (I use an amplifier with an output impedance of more than 1200 Ω and I have drivers with non-conducting voice coil formers). Then you have a stable frequency response (and resonance) and you can make it (and the resonance) what you want (dampen, correct, tune, extend) and the distortion in the drivers is much lower (total lack of current distortion, see website Klippel also, for more information). There is one caveat: a high output impedance doesn’t work with traditional (voltage) passive crossovers. You need redesigned passive crossovers (see Nelson Pass) or active crossovers, even better.
Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
@@toktok3796 No, I don't have a recommendation for an amp for those speakers. High impedance / transconductance amplifiers and redesigned crossovers are a totally different path, and probably DIY... The suggestions I have is: - Find out if it is really lack of control or if it is a setup/room issue. - Experiment with setup first. - Try to correct with (parametric) EQ or DRC.
One of the seminars I used to give on loudspeakers and amps included demoing Damping Factor. Very easy to do. Take any speaker, the larger the woofer the better, with it disconnected from any amp, tap on the woofer cone and listen to the resonance. Then short the speaker terminals, a piece of wire, I would use my keys, and tap on the woofer. The amount of control exerted on the woofer by itself, the counter EMF allowed to flow in the completed circuit, is extremely audible. To then explain how a high damping factor means low internal resistance in the amp, like the keys shorting the terminals. And how that allows a speaker to control it's own excessive reaction to a signal.
@@BubblePuppy. Yes, a wire moving through a magnetic field generates a voltage. It is in the reverse direction (polarity) to the voltage sent by the amp. It is called Counter EMF (Electro Motive Force).
Damping Factor is the mathematical ratio of the speaker impedance to the amplifiers output. A perfect solidstate amp would have a zero ohm output stage. It would act like the keys and allow the counter EMF to feed back and control itself.
With no load on the speaker you are hearing basic resonance of the driver/ cabinet. With a short you are hearing how a good amp takes control of that speaker system.
Fascinating insight. Thank you!
That was a excellent and simple explanation...
So high damping factor in the amp does not matter for the speaker control?
@@jeffriver9715 I'm assuming you posted this in the wrong place. It makes no sense RE what I posted.
Hi Paul. Thank you for your patient knowledge and experience sharing. Great Videos.
Regarding an output of an amplifier impedance, In my experience and knowledge, it should be lower such that it's presence will not be a noticeable. The actual damping impedance for the driver of the speaker is the sum of:
a. Amplifier output impedance
b. Amplifier Binding Posts (Both Plus and Minus) to speaker wires resistance ( Let's assume 0.05 Ohm)
c. Speaker cable impedance (Both Positive and Negative, lets assume 0.1 Ohm for 2 meters cable)
d. Speaker Cabinet Binding Post (Both) (Let's Assume 0.05 Ohms)
e. (In some Cheap Speakers) Speaker internal wiring ( lets assume 0 Ohm)
f. Cross Over Coils internal DC resistance (lets assume 0.2 Ohm)
g, Speaker Driver internal DC Resistance (usually few ohms, but let's assume 0 Ohms)
i. For the Woofer: Serial Coil impedance at Pass Area, i.e if upper 3dB cut frequency for the woofer is 1000Hz (for 2 order C.O), it means that coil impedance at 1000Hz is ~ 4 ohms, it means that at 100Hz Coil impedance = 0.4 ohms and 0.1Ohm at 25Hz
So by this example we see between the amplifier and the speaker added resistance /impedance of ~0.8 Ohm @ 100Hz
If my example is close to real life, it means that an output impedance of 0.08 Ohms = Damping factor of 100 is more then enough for an amplifier.
As per Feedback, too much feedback kills the Power amp slew rate (Rise time) ability. A high Slew rate is a parameter not so known or looked at, but IMHO very important indicator for the amplifier bandwidth, speaker synergy behavior and clarity.
Thanks and best regards
Thank you Paul. I really appreciate these videos and the time you spend to make them. Best on TH-cam by far. Have lived in evergreen Golden Denver Lakewood Aurora Littleton and conifer. I live in fort Worth Texas at the moment but someday I'll make it back.
I’ve been watching your videos for quite awhile now. You are one smart dude! Thanks for helping me to learn more about music reproduction.
In my old car stereo days, everyone knew Fosgate Punch and the new-comer HiFonics amps had big damping factor for that big bass hit. Then outboard caps came along with crazy subs like Sundown (sp?), which really gave the hobbyist who likes bass, something really nutty.
This is a great series; picking a speaker with high impedance can drastically lower the damping factor of an amp, so knowing speaker impedance and amp output is important, especially when it comes to low sensitivity speakers that hover around the mid 80’s dB per watt sensitivity and pairing that up with say a low output tube triode mode amp that say makes 10 and less watts per channel. Keep up the good work.
"picking a speaker with high impedance can drastically lower the damping factor of an amp"
The damping Factor of an amp is a set measurable number. Basically it is the amps' "output impedance". It does not change based on what it is connected to any more than it's input impedance. You could go from a 2 ohm load to a 2M ohm load and the amp's output impedance would stay the same. And it would not change what number is published for an amp's Damping Factor as that is just the ratio of that output impedance into an 8 ohn load.
@Douglas Blake I guess I just don't get the fascination with forcing "Damping Factor" into usage it has no place in. DF is simply one spec to help evaluate an amp on paper. An indirect way to publish an amp's output impedance using bigger nontechnical numbers. "Damping Factor: 100" looks much better on a spec sheet than "Output impedance: 0.08 ohms".
If one pretended DF to be of value in an actual installation with typical speakers (maybe 6 ohms - 30 ohms 20-20Khz) the system spec for an amp with a published DF of 10 would show "DF: 7.5 - 37.5, 20 - 20Khz.". This additional, strictly mathematical process does not provide any new insighs.
@Douglas Blake two issues. Both involve trying to twist a simple indirect published specification into something it is not. Basically A/B=C. For DF: A = amp output impedance, B = 8 ohms, C = DF. Yes you could continue to use the formula A/B=C with A = amp output impedance, B = (some external value, instantaneous speaker impedance at given freq, total wire/ speaker @ freq) with the resultant C = some number that will then be called "Damping factor". But other than using the non-changing Amp output impedance, the results has nothing to do with what the term "Damping Factor" as published in an amp's specs means. You could just as easily use A/B=C with A = 1550 ohms (Shure M97), B= 47K ohms (preamp input) and claim that circuit has a Damping Factor of 0.033. It comes down to trying to use the term "Damping Factor" where it was never intended to apply. It is nothing other than a way of spec'ing an amp's output impedance.
Next that a DF of 10 is sufficient. Again, sticking to the actual definition of "Damping Factor" as the published output impedance based on an 8 ohm load, that would mean a 0.8 ohm output impedance. The same results as adding 400 feet of 12 ga lamp cord to an amp with a 1,000 DF when driving an 8 ohm load. I would not find that acceptable.
@Douglas Blake You are correct that I started out by correctly explaining that "Damping Factor" is a number published as a spec by amp manufacturers determined by dividing the output impedance of that specific amp by the number 8 to represent an 8 ohm non-inductive load. that number as published has nothing to do with how that amp might be used in the future, what it might be connected to, how many feet of cable, what brand speaker, the speaker's constantly changing impedance, humidity nor latitude.
Just as the published S/N of an amp has nothing to do with the room it is later put in and the room's noise floor. It is just as irrelevant to claim an amp with a published S/N of 110db has a S/N of 70db because of room noise.
This has been true since I received my degree in electronics, got an FCC Broadcast license, spent the 1st 10 years of my giving lectures and clinics in Audio for some of the top manufacturers, (Marantz, AR, AT, Kenwood, Maxell, Pioneer Auto, ...) over 50 years ago. Including running a regional Kewood repair facility. To then move to Broadcast Video including entire TV video facilities and satellite uplink vehicles. and then to CGI selling the systems Jurassic Park and Terminator came out of. Not to mention my dedicated 56k link to ARPANet, now called the Internet. Wrapping up with leading edge IT products shipped around the world.
so with the facts solidly behind me, I will not be changing my mind soon.
Super job by Paul on this one. One way to better understand this is to connect an analog voltmeter across a cone speaker terminals and measure the changing voltage as you gently push the cone in and let it come out. The voltmeter will register the changing voltage. The amplifier has to control/sink that generated voltage/current. Also "Damping Factor" is frequency dependent. An amplifiers damping factor will be different at 60Hz than it is a 10Khz.
A very effective demo is to tap the woofer on a disconnected speaker. (larger the better) then short the speaker terminals and tap again. The difference is extremely audible and a direct demo of what damping factor does.
@@glenncurry3041 Have you ever used a speaker as a microphone? As I kid ( a long long time ago ) I tried that and it kinda works.
@@wilcalint Yes that is exactly the Counter EMF, the voltage generated by wires moving in a magnetic field, that needs to be shorted out, needs to be allowed to control the driver instead. And that is what the DF number tells you. How close to a dead short is the output of the amp so this Counter EMF can be controlled. The number is just a ratio between the amp's output impedance and an 8ohm load. A DF of 100 just means 8ohms/100 = 0.08 ohm output impedance.
another way to look at this is 12ga zip cord is 0.02 per 10ft. So an amp with a DF of 100 is like adding 40ft of lamp cord.
Great topic. I find these posts interesting in themselves. Often it prompts me to read further to understand the topic at a deeper level that possible in these brief videos. In this case I spent an hour reading AudioReality which covers this very well in layman's terms.
A great way of explaining it without making it complicated!
I love my Hegel Norway H80. It's just a baby at 75Wpc. But has 1000+ dampening factor.
All is Full of Love by Bjork can sound absolutely terrible on a lot of sub $4000 integrated amplifier's but this guy at $2000 when new in 2014 was Holy moly WOW. Absolutely no listening fatigue yet still sounds commanding/powerful!
My Bryston 3bst has a very high damping factor. It takes total control of the speaker; sound is very quick and tight. So its quite common to pair a tube preamp with them to tame them.
I had a 4bst and noticed the same traits. Unfortunately, I sold it before I really found the right preamp for it.
My own anecdotal experience gained over a course of 45 years of owning one amp or another is that damping has a sweet spot, and that amps with very high damping factors just don’t sound very good. I doubt that anything over 200 or so is actually beneficial especially with speakers that have over damped low ends to begin with.
You're not alone, and not the first...
See the two articles from 1954 and 1955 (!!) by D.J. Tomcik: Missing Link in Speaker Operation, Parts 1 & 2:
- The Amplifier Damping Factor and its Application to Speaker Performance
- Obtaining Variable Damping Factors in Amplifiers; Determining Critical Damping Factors
And, on top of all that, the actual electric damping is heavily modulated by a continuously changing voice coil resistance.
Having Paul comment/answer all these questions, i do learn alot. OTOH, reading the comments sections, one can also learn in depth what was asked....But am still lost here :-)
Don't overcomplicate it. Damping factor simply relates to the output impedance of the amplifier in relation to the speaker.
A speaker is a kind of motor; and, like many motors it becomes a generator when used backward. As a speaker moves it generates momentum and tends not to want to stop. Then it acts like a spring and wants to snap back -- overshooting equilibrium and causing an unwanted resonance. You can hear this as ringing in your system.
While the speaker is resonating, it is actually generating electricity since the speaker coil is resonating in the magnetic field of the magnet. So the amplifier can prevent the "ringing" by sinking the electricity that the speaker resonance is generating. However, impedance between the coil and the amplifier will slow this process down and inhibit the ability of the amplifier to absorb the ringing in a timely manner.
@@timharig Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
thank you mr. Paul
The resultant listener experience with damping factor is in speaker cone control, and that means distortion, since the most distortion is introduced in the speakers. Big speaker cones at large volume with low frequencies are not easily controlled.
So many interesting things here. But one nobody bothers to ask and it was how high is Paul’s damping factor?? hehehe it was ALMOST a joke Paul!
Great stuff keep it coming. 👍👍
Does this information apply to car audio amplifiers as well
Hi Paul, why is it that listening to your explanation is better than reading all those materials? Greetings from the Philippines....
Damping Factor is only one of many factors that affecting the damping ratio denoted by ζ (zeta) of a speaker system. To achive best speaker sound, the damping ratio must be tuned to a proper value depending on the design of the speaker system. For any speaker system, there must be a best matching amplifier outpout impedance. In old days when speakers were designed for high output impedance vacuum tube amplifiers, damping of speakers were mainly done by mechanical means. Nowadays speaker dampings are partly mechanical and partly electrical since solid state amplifiers have low output impedence. So, whether high damping factor is good or not depends on what speaker to be used. Furthermore since amplifier output impedance is connected in series with speakers, as long as speaker impedance plus cable impedance dominates the total series impedance say 99%, further reduction of amplyfier output impedanc makes no noticeable differences. Therefore a damping factor of 100 is high enough. Increasing damping factor above 100 has negligible effect.
Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
And it’s not constant with frequency, - because it is a ratio and the speaker impedance is not constant
Rather than passive damping, you can have active damping with servo feedback. This is especially possible for a subwoofer but much harder to engineer for superior performance.
You are 100% wrong here.
The servo doesn't do ANY damping, it does correction on cone overshoot. It can, by the way be done full range. Philips did that with "Motional feedback" as they call it very long time ago already. So damping factor of an amp and a serve controlling a box speaker are 2 totally different things.
If the damping factor of the amp is not good enough, your input to the speaker is distorted. Nothing any servo can do to correct that.
Maybe ask Paul.
@@ESL-Plus Damping is about reducing resonant ring of the cone. The damping factor is about how effectively the amplifier can short the voice coil to cause an electromagnetic brake of the motion. Ideally the amplifier is having zero Ohms output impedance for maximum damping. Active damping means your amplifier is actively damping the resonant ring by applying an opposite signal to the ring for even more effective damping than zero Ohms. A servo subwoofer (e.g. my Velodyne sub) is using such principle and Philips introduced it decades ago.
@@ThinkingBetter Paul mentioned in his video (and that is a fact), that the amps output changes because of the reactance (3 factors: impedance, inductance and capacitance) of the speaker. Your servo doesn't change the speakers reactance (combination of multiple coils and a cross-over) to the amp, it only acts as a mechanical correction.
Sorry
@@ESL-Plus First, impedance includes resistance, inductance and capacitance. Reactance is just the non resistive part of impedance. Damping factor is the ratio between the loudspeaker impedance and the total impedance driving it. An amplifier with high damping factor has low output impedance causing a more effective short circuit of the voice coil against unwanted resonant oscillation. A servo feedback goes a step further in damping the voice coil motion actively by applying an opposite phase signal (feedback loop) during the resonant ringing further damping it.
Is the damping factor related to Maximum Transfer of Power in some way. When and where does matching impedandces come into play.
people over think the output Z too much when it comes to headphone systems. Most headphones aren't sensitive to impedance matching with the amp. IMHO, low output Z on the amp doesn't mean it will sound best. e.g. a tube amp has higher output Z and it sounds more "natural" than solid state with under 1 Ohm output Z. I would say for headphone amps, 5-15 Ohms output Z is good middle point.
Some Hegel amps have 4000 and they sound amazing.
A lot of cars are red and drive very fast. But the question is: do they drive fast because they are red?
The same goes for damping factor!
Jerry the answer is yes, absolutely red is the fastest color. Did you ever see a fast turtle, no because they aren't red.
They practice some miracles there
Yeah, a DF of 4000 is just a 4 ohm speaker driven by an amp output impedance of 0.001 ohms, which is about the minimum output impedance you'd really realistically want in an audio power amp for good, full sound. On the high end you don't want much above 0.01 ohms of audio amp output impedance, like Paul said, and that amount which when driving a 4 ohm load, would then be a DF of 400.
I've seen amps (and receivers) with DF of between just below 100, (like 80 or so), and a few thousand, like those Hegel amps you mention. Anywhere in that range is good DF for an audio amp, but you just don't want anything much above (or below) that range because it will start to reach that point of sound degradation, as Paul mentioned here.
@@JoeJ-8282 Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
Just got an old Crown D75, and I’m pleased as a peach to have such a robust utilitarian amp.
There's an older Rotel poweramp which damping factor is 2000.
Most new stereo and poweramps are around 200, unless they're really expensive.
Just create a amp output with a ton of negative feedback. That way you have a high damping factor! 👍
In order to utilize a high damping factor (low output impedance) to the fullest extent possible you must use very heavy Gauge speaker cables.
Hegel has high damping factor, thats not the reason i bought it, i like them as pakage, they have very good controll and good details in the sound without being bright
Yeah, I love my H160. It's very clean and controlled, no hiss or noise of any kind no matter the volume.
I used to have a h360 that served me well. I gave moved on to a krell duo 300XD that I like even more.
I have a H300, it sounds pretty nice.
The you don't understand what Damping Factor is. DF helps show how well an amp is able to control (damp) a speaker so it can "have very good controll and good details in the sound". A high damping factor can mean the amp can better control the speakers' movement. Force it to do what it wants.
I understand what damping factor is, i just said that its not the only reason i bought hegel
I get intermittent pauses in audio only while streaming and only in surround sound. If I turn off surround and just use the TV speaker it is eliminated. Using all HDMI or ARC cables. System
Sony TV XBR 75X900H
Receiver Yamaha RX-V685
FIOS fiberoptic box
Sony BluRay
Paradigm 6 speakers including the subwoofer
Any ideas on a solution or who I can ask on what to do?
TY
The AT2505 AMPLIFIERS have a damping factor greater than 1000 from 20Hz to over 400Hz.
8ohm speaker divided by .01 is 800 which is a very high damping factor for a power amp. Did you mean 8ohms divided by .1 which would be a damping factor of 80?
could you say that output impedance is determined by resistance through the output transistors?
It's determined by the circuit. In an emitter-follower topology the transistor has fair amount to say about it; but, so do things like the power supply that is supplying the transistor.
is 40 good for a 6ohm speakwrs
What is output impedance anyway? Which part of the circuitry has output impedance?
Every output can be defined as a Thévenin equivalent source with an idea voltage source in series with an impedance:
en.m.wikipedia.org/wiki/Th%C3%A9venin's_theorem
It isn't necessarily a single component that creates the impedance. It is a result of the entire circuit topology and everything in it.
I asked a similar question. My amp is newer and my speakers are 1969. And I am still a bit confused 😕
Depends on the speakers what sensitivity are there what Ohm's what is the damping factor of your amplifier
@Douglas Blake Thank you I think that was reassuring
@Douglas Blake Manufacturers almost always (unless stated otherwise) use 8ohms as the load to calculate their DF. And often only at one freq (400hz sinewave?) Which adds confusion to the whole discussion. Few "8 ohm" speakers stay anywhere near 8 ohms across most of the freq range. Some going up to 30 ohms or higher and my Maggies down to 2ohms above 2k. And amps can change output impedance at different frequencies as well.
An amp with a DF of 10 would mean 0.8ohm output impedance. Even if they measured 20-20khz my 2ohm @ 2Khz would mean my DF would be 2/.8 = 2.5.
Now, 10ft of 12ga wire is roughly 0.04ohms. We spend a fortune on better wires to drop that even the slightest bit lower? But accept adding 0.8ohms on top of it?
So no a stated DF of 10 is not good enough. While yes there is a point of diminishing return, it should be at least 100. That at least means only twice as bad as zip cord.
I have a vintage amp with newer speakers, I think that's the way to go. The speakers are super analytical/revealing (too clean) but the old class A amp gives it some warmth and nice distortion.
@Douglas Blake No I did not miss that. Again a DF is measured into 8ohms. That is what that number is. A DF of 10 mans the amp has a 0.8 ohm impedance. That impedance does not change as the speaker load changes. If you go to a 4ohm speak that same amp will have a DF for that speaker at it's 4ohm spot of 5. Thus not even meeting your 10 requirement and it is the same amp.
And again, a DF of 10 (@8ohms) is equivalent to 200 ft of 12 ga zip cord. And you consider that acceptable?
And once more, most amps only list the DF at one frequency when it changes across the audio spectrum. So even that DF 10 will be well below that at other frequencies.
As Paul says, 100 minimum. And across 20-20Khz.
My First watt f6 diy has a damping factor of 16 in 8ohm,and output impedance of 0.5ohm
How is the bass from that amplifier?
@@jeffriver9715 it´s ok, better than schiit ragnarok 2.
My amp has 15.sounds lovely 😍 class ab push pull .6550.😊❤
Zero feedback single-ended triode (SET) tube amps tend to have a very low damping factor - around 2 to 10 depending on the size of the output transformer. Push pull tube amps with feedback have higher damping factor. Typical solid state class AB designs have a damping factor over 100. From a design standpoint, some engineers consider the output filters of a typical modern class D power amp will lower its damping factor when compared to a direct coupled class AB solid state amp.
@Douglas Blake An inductor that has an impedance of 0.001 ohms from 20 Hz to 20 KHz then having a gradual rising impedance starting at about 8 ohms at 60 KHz? 🤔
@@laurentzduba1298 Exact formula for inductor impedance is RL(f)=2*𝝅*f*L, where f - frequency, L - inductance in Henry (after Joseph Henry), while symbol L is after Heinrich Lenz.
the impedance of an inductor based on the value of the inductance, L, of the inductor and the frequency, f, of the signal passing through the inductor, according to the formula, XL= 2πfL.
@@kalijasin Thank you.
My japanese Denon PMA 720 makes every speaker its beee-atch. Can't even turn it up past 1/4th volume. Could be devastating.
I have pma 2000 ivr
Yes it drive my b&w 801 s3 no more then 9.00 or 10.00 oclook
I to high vol teromnsos bass open clere mis ..superb clerty on highs as you see the music
This is my 3th denon
From 1988 i haed pma 6600 / pma 1060
This one is what i need for 801 ...
Best refards
You well see it in my chhanal
IL
Great video as always dear Paul :-)
My 23 years old Yamaha AX-592 has Damping factor: 320 is this number good ??
Better than my AX-390 with only 100
I think this number of 100 is a kind of stardand at Yamaha. Just like 60 at Onkyo's
8 people who disliked this video has very low damping factor to understand Paul !!!
the point here is... how to measure output impedance of amplifier ?
In general I would have thought the the DF of a speaker would be far more important. Bass anyway
In pa we seek high imput z and low output z
Damping factor ...... oh boy !!
Firstly an amplifier output should be non reactive so it won't have impedance ... only resistive ! Secondly if you are familiar with typical speaker impedance curves you will notice the peak in impedance at the resonance where the impedance figure can rise much more than the nominal impedance.. here the damping factor can be very much higher.
Outputs are only non-reactive if direct coupled solidstate. Tubes (most) use transformers which have high inductive reactance. Some SS amps use DC blocking on the output. Most include a small I/C or R/C circuit in their outputs to stop "speaker cable resonance". And today's digital or Class D? But yes the closer to purely resistive the better.
But this again confuses what "Damping Factor" actually is. It ia nothing more than a number for the ratio between the amp's output impedance and 8ohms. How the number is determined has nothing to do with eventual usage. e.g. a 100DF @ 8ohms is a 0.08ohm output impedance. changes in the load do not change that value. Nor do they change how a manufacturer publishes a DF @ 8 ohms number.
@@glenncurry3041 the DF is the source ( amplifier) impedance divided into the QUOTED speaker impedance. But in the real world we know this is not the case ... the DF will vary according to the overall shape of the speaker impedance curve 😃
Ohh man, what a workstation for background. Hurts my head. xD
Everything in system design is a compromise and obsessing on damping factor as the bad boy is not helpful. Improving the damping factor can cause other issues in amplifier design especially when it comes to negative feedback. Also some speakers can sound less sterile when using an amplifier with a poorer damping factor.
My Bryston B60P at 4 ohms is What I listen to my records and music on V.s when I listen to my kitchen syestem is a little cheap class d FEEDBACK is definitely something better built amps take care of very nicely
Anyone please help me out.
Should I get online ups for power amplifiers?
Not sure what you're trying to say online-ups? what is that what do you mean by online
@@johnsweda2999 I believe he means double conversion ups. Also called online, since the DC/AC inverter is always connected on. As opposed to the other two types of ups, the offline/stand by and the line interactive architecture.
Dampingfactor of 100 and more is theory, cause in line with the Speaker are the Cable, Connectors and if passiv the crossoverparts. Only way to have the benefit from a high dampingfactor is an activ speaker system. A passiv System not higher than 8 for an 8 ohm System, or 4 for a 4 Ohm system
A manufacturer measures and publishes Damping Factor as measured into an 8 ohm load. That published spec has nothing to do with external wiring, speakers or crossovers. It is a completely meaningless and useless number other than a way to get the output impedance of the amp. Chosen because the numbers look better than the technical equivalent.
@@glenncurry3041 yes right, the number is meaningless, a other description for a output impedance. for the whole thing you must also add the the impedance ,all parts between the amp and the speaker. A assumption from 1 ohm for the parts is real. The speaker(the generator) sees a load from 1 ohm and the output impedance from the amp. For the speaker it is no difference if it is 1ohm (parts) and 0,01 ohm (amp) or 1 ohm and 0,1 ohm. A activ system can minimize the parts impedance, short soldered cables, no crossover, no connectors
@@cbts001a4 Make sure you first give any wire connections a solid crimp before soldering. Crimping is actually a better lower resistance connection than soldering. Solder has 5-7 times the rsitance of copper.
The coils and wires may add up to a half Ohm maybe, then factor in an additional 6 Ohms of series resistance within the 8 Ohms driver. So the system damping factor can never get better than 1.33. So forget 100, 800 or 4000 damping factor. You still end up at 1.33
Anyone can look up any spec’s and what they mean online.
You can also look up the ingredients to a Boston Crème Pie, and buy one online, but making it from a recipe is much more gratifying. I like Paul's explanations.
Ok guys, is damping factor a 2 way thing??. I mean; is the amp damping the forward cone motion when it's time too, as well as cone return???
@Douglas Blake Thanks! that's what i thought.
Depends on the speakers you got high efficiency speakers at 98-99 DB then really you want a low damping factor 60 to 120 damping factor up to 300 is fine you don't need to go any higher than that. Only caveat is if you're playing subwoofers bass reflex then maybe up to 600
Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
Just give us the output impedance of the amplifier, the DF number is just a construct. The idea that the amplifier can add damping is a mathematical myth since you would need a negative impedance to improve amplifier damping and a positive number can only make the damping worse. The T-S equation that defines (2Pi*Fs*MMs*Re)/(BL)^2 where Re is always a positive number that must be the _added_ value in Ohm of the output impedance of the amplifier _plus_ the impedance of the speaker. Note there is no partial division of Re parts of the impedance of the speaker versus the output impedence. They cannot be divided, they must be _added._ But I am sure that even those solid numbers will stop the DF myth. Also, T-S tells us in no uncertain terms that the damping of the loudspeaker *_is entirely defined by the alignment._* So the output impedance is only a part of what can _modify_ the alignment. But if you equalise the current of the amplifier, so that all frequencies below 200 Hertz the current is the same (flat impedance), this will in effect cancel out the output impedance of the amplifier in the sense that the amplifier output impedance cannot change the alignment. This is not theory, it is a fact, both mathematically correct, and that there are now several DIY loudspeaker designs that do this - *_the output impedance of the amplifier can no longer influence the alignment._*
With electrostatic speaker systems, damping factor would be irrelevant!
Yes, and no. It takes a lot of instantaneous current to move something that is purely capacitive. If you only fed it voltage and almost no current, the capacitance of the panel would act as a low pass filter. Lower output impedance (at the same high voltage) would have better control.
Same goes for electrostatic headphones, the Stax SR-007 being famously harder to drive, due to higher capacitance. Thankfully many electrostatic speakers have amps built in. If it uses transformers, that damping factor still applies as it multiplies the effective capacitance seen by the amp.
Most amps at that voltage already have enough current, even transformerless tube.
Damping factor is pointless without demonstrating stability on phase changes. German audio magazines test amps. by showing damping as function of phase change or stability. But then .. only in Germany they understand how to build good amplifiers ....
what German amp do you recommend for
Good measurements do not equal good sound.
簡単に言えば、ダンピング能力を、いくら大きくしても、再生音は、美しくはならない、ほかの大切な高調波迄も、鈍くしてしまうから、
この事は、始めに、目的をはっきりさせないと、違う答えに、なる。スピーカーを制動させる、必要が目的なのか？それとも、元々、ユニットが初めから持っている能力を、すこし補助することなのか？もし、ユニットに、アンプが制動をかけコントロールすることが、目的とするなら、それは、無駄な事に、終わるでしょう、
You don’t need electromagnetic damping and you don’t want electromagnetic damping.
Of all the ways of damping electromagnetic damping is by far the worst.
And why is it bad?
* It is unpredictable. A lot of factors have their influence on electromagnetic damping: Amplifier output impedance, cable impedances, voice coil impedance, voice coil temperature (and thus room temperature and how loud you play). So, you have no control over the amount of electromagnetic damping. So, you have no control over what the driver is doing.
* Electromagnetic damping is making use of the driver as a generator, as a microphone. It doesn’t only pick up the cone resonance, it picks up all cone movements: external sounds, sounds inside the enclosure, cone vibrations, added harmonics, port noise, noise from ferro-fluids, noise from eddy currents, etc. The generated signals distorts the input signal, the lower the output impedance (the higher the damping factor) the more distortion.
* For electromagnetic damping you need a low output impedance (a high damping factor), which makes the current and thus the output of the driver sensitive not only to back-emf (“the microphone signal”), but also to the voice coil inductance and the voice coil resistance.
* The inductance is not constant, it is modulated by excursion and by current. As every ferromagnetic filled coil this creates phase shifts, modulated noise, distortion and especially (added) intermodulation distortion (till 30%, see the website of Klippel for more information).
* The resistance is not constant. It is modulated by temperature, and thus also modulated by the music itself. Changes in voice coil temperature changes the output (thermal compression), changes the electromagnetic damping and changes the frequency response. The thermal compression is driver impedance dependent and thus frequency dependent.
* And above all, electrodynamic drivers are driven by current (201 years ago, already, Ørsted found that it is the current and not the voltage that creates the magnetic field and thus the force). So, when having a low output impedance (which makes the amplifier a voltage source) you give the opportunity to have all kinds of impedances and voltages (EMF) their influence (compression, distortion and modulated noise).
There is also another form of electromagnetic damping. The movement of the voice coil generates eddy currents in conducting voice coil formers, which create modulated noise. And that is picked up by the microphone effect and added to the input signal.
To get rid of all these effects you need two things: a high output impedance, 800 Ω or more, and non-conducting voice coil formers (I use an amplifier with an output impedance of more than 1200 Ω and I have drivers with non-conducting voice coil formers). Then you have a stable frequency response (and resonance) and you can make it (and the resonance) what you want (dampen, correct, tune, extend) and the distortion in the drivers is much lower (total lack of current distortion, see website Klippel also, for more information).
There is one caveat: a high output impedance doesn’t work with traditional (voltage) passive crossovers. You need redesigned passive crossovers (see Nelson Pass) or active crossovers, even better.
Thank u for that insight! Which amplifier would you recommend for the JBL XPL200 Stereo Speakers? My amp (Sansui AU-G90X) isnt able to control the big cones very well.. do u have a good recommendation for an amp that can handle those beasts more confidently? :-)
@@toktok3796 No, I don't have a recommendation for an amp for those speakers.
High impedance / transconductance amplifiers and redesigned crossovers are a totally different path, and probably DIY...
The suggestions I have is:
- Find out if it is really lack of control or if it is a setup/room issue.
- Experiment with setup first.
- Try to correct with (parametric) EQ or DRC.
@@JerryRutten thank u so much for ur answer! I will try to reach more with room acoustics and room correction via dsp…0