LINEAR DAMPING FACTOR (20-20kHz)

baboon · February 2005

LINEAR DAMPING FACTOR (20-20kHz)

what does that mean? the measure ment for it? like 140 or more. Thanks!

baboon · February 2005

Originally posted by baboon
LINEAR DAMPING FACTOR (20-20kHz)

what does that mean? the measure ment for it? like 140 or more. Thanks!

For a Reciever/Amplifier

madmax · February 2005

140 to 200 is a really good number. The higher the number the better the control over the driver. Do a search. Somewhere it was explained exactly how to calculate the number. Older tube amps had numbers somewhere in the 50's.
madmax

trubluluc · February 2005

Think of damping factor.....
...like shock absorbers, controling your wheels.
It helps the amps ability to control and stabilize your speakers drivers.

Now of course as in most things,
people tend to think "More is Better",
but it's not always the case.
More important is the relationship between your amp and speakers.
Some speakers don't need alot of damping to remain accurate.
The "20-20,000khz" is simply the range of sound in hertz, 20 being the bass end of things.

-Luc

Toxis · February 2005

not to mention, you can have an amp with 150 damping factor and another with 1500 and there's very little difference audibly about it. I used to think DF was a pretty good stat to look at but then I read an amplifier design book and it broke it down for me. Not really necessary to know/worry about now.

bknauss · February 2005

Generally this is a very bloated number... wouldn't use it as a determining factor when buying an amp/receiver/whatever.

F1nut · February 2005

Originally posted by Toxis
you can have an amp with 150 damping factor and another with 1500 and there's very little difference audibly about it.

Ah, but the difference between 50 and 150 is audible. You'll hear it when the woofers bottom out. While it's not the only spec to look at, it is very important to know if the amp can control the drivers or not at higher volume levels.

George Grand · February 2005

I don't think anybody answered it in terms the novices can understand.

Damping factor is the ability of the amp to stop the driver when the sonic signal is no longer there, and also stop the driver from bottoming out. You want the woofer to stop woofing when it is supposed to musically, and mechanically. The higher the damping factor numerically, REPUTEDLY indicates a better ability to do the above mentioned jobs.

You overdrive the snot out of a woofer, no amount of DF is going to stop it from bottoming out.

George Grand (of the Jersey Grands)

F1nut · February 2005

Woof

faster100 · February 2005

well if its not important, why are some amps rated at <100 and some at < 800 thats a huge difference.. just wondering

George Grand · February 2005

ARF you silly dog.

Faster,

Probably for the same reasons Krells are built so that you could throw one down a flight of concrete steps without harming it. I would treat both a Carver and a Krell like I was carrying a newborn. Get the picture?

George Grand (of the Jersey Grands)

faster100 · February 2005

Yup, Thanks

George Grand · February 2005

My pleasure friend.

George Grand (of the Jersey Grands)

RuSsMaN · February 2005

Also worth a mention, you can overdamp a driver with TOO high a DF, just as you can by overdamping the cabinet it is in.

Anything 50-300 is usually a good place to be, for smaller, common drivers today. Ie 5" - 8". You start talking DF's up the 1500 range etc, won't do you a bit of good (and may actually sound worse) unless you are running a few big open baffle 15's or 18's.

Cheers,
Russ

DarqueKnight · February 2005

Damping factor is an amplifier performance specification that is the ratio of the speaker's input impedance to the amplifier's internal inpedance. Put another way, it is the amplifier's output impedance divided into the speaker's input impedance.

For solid state amplifiers, the damping factor is usually calculated by dividing the amplifier's output impedance into an 8 ohm speaker impedance. For transformer coupled amplifiers, like tube amplifiers, the damping factor is usually usually calculated by dividing the amplifier's tap impedance into an 8 ohm speaker impedance.

Since a speaker's input impedance is reactive and varies with frequency, the damping factor will vary with frequency. Some amplifiers with very low output impedance have the ability to maintain a minimum (or linear) damping factor over a range of frequencies (e.g. 20 Hz to 20 kHz). Amplifiers with non-linear damping factor characteristics will usually list the damping factor at one particular frequency, usually 1000 Hz.

An amplifier with a high damping factor amplifier is not necessarily better than one with a low damping factor. An important thing to consider when matching amplifiers and speakers is the design philosophy of the speaker manufacturer. Some speakers are designed to perform best with low damping factor amplifiers. Others are designed to perform best with high damping factor amplifiers.

jrlouie · February 2005

Interesting reading. This is definitely another part of home audio that I don't know about. I love it, you guys know everything

If nobody minds I'd like to pose a question. What about the Lsi series? What would anyone recommend for a damping factor on those great pups?

The amp I'm powering my Ls15's has a damping factor of 800:1 @ 100hz with 325watts/channel @ 4ohms. I know there are lots of other pieces that mate an amp well with a set of speakers, but lets just talk DF.

DarqueKnight · February 2005

Originally posted by jrlouie
What about the Lsi series? What would anyone recommend for a damping factor on those great pups?

Polk's customer service would be the best source for an answer to that question. You might also post this question in the "Basic Hookup/Wiring Questions" forum. It is moderated by Polk's customer service manager, Ken Swauger.

disneyjoe7 · February 2005

With tube amps being in the 50's why do so many here prefer a tube power amp? Wouldn't a tube pre with a SS power amp be the best of both worlds? Warm sounding with that Damping muscle.

F1nut · February 2005

Originally posted by disneyjoe7
Wouldn't a tube pre with a SS power amp be the best of both worlds?

Many believe that is the best combo, I do.

disneyjoe7 · February 2005

Jesse,

Isn't pass your bed time, I think it's pass mine. I'm on a new **** shift at work 12am till 8am on a laptop due to work computers restrictions on this website among others also.

BTW thanks I plan on doing just that in the future Tube Pre / SS amp.

F1nut · February 2005

Steve,

Nah man, it's prime time!

disneyjoe7 · February 2005

Jesus dud what does your Batteries run on?

F1nut · February 2005

These days, Duracell. I screwed the bunny, so they won't let me near it again.

Edit for spelling........looks like I need to change batteries.

disneyjoe7 · February 2005

Originally posted by F1nut
Thses days, Duracell. I screwed the bunny, so they won't let me near it again.

LOL

I needed that

bknauss · March 2005

Originally posted by jrlouie
Interesting reading. This is definitely another part of home audio that I don't know about. I love it, you guys know everything

If nobody minds I'd like to pose a question. What about the Lsi series? What would anyone recommend for a damping factor on those great pups?

The amp I'm powering my Ls15's has a damping factor of 800:1 @ 100hz with 325watts/channel @ 4ohms. I know there are lots of other pieces that mate an amp well with a set of speakers, but lets just talk DF.

Given that there isn't a real standard for measuring DF and you generally see bloated numbers, this is too focused of a question. I say listen to different amps if possible and decide which you like best.

John K. · March 2005

BB, as has already been pointed out, damping factor is the ratio of a speaker's nominal impedance(e.g. 8 ohms)to the output impedance of the amplifier, which is typically 0.1 ohm or lower in any competently designed receiver/amp. Therefore the nominal damping factor typically would be at least 80 (8 ohms/0.1 ohm)in even inexpensive equipment. An exception to this would be certain amplifiers, particularly some tube amplifiers, which aren't well-designed from this standpoint and have output impedances of several ohms, resulting in a damping factor of around 1 or 2. The "linear" part of the claim results from the contention that the output impedance of the amplifier doesn't vary much between 20-20KHz and that the nominal damping factor is therefore "linear" over that range.

This area is yet another example of over-hype in audio, although at least here the matter has some factual basis, which is lacking in so many other audio claims which have no audible benefits. An excellent discussion of this by speaker designer Dick Pierce is found here . Until damping factor would get down into the low single digits no significant difference results in either speaker control at bass resonance or in frequency response fluctuation with swings in speaker impedance. A difference between damping factors of 20 or 200, for example, isn't of audible significance, whether it's "linear" or not, and this shouldn't be an area of concern to listeners.

F1nut · March 2005

How many Google searches did you have to do to come up with that one??? Guess what, I can Google too and quess what, this is from the first hit.

"If you don't understand basic electric current and voltage, let's just say that damping factor is a figure of merit that tells you how good an amplifier is at controlling a speaker system. The larger the number, the better it is. At 100 or above, it's pretty darned good. Below 20 or so, it's pretty poor.
When one amplifier's damping factor is higher than another's, that tells you that the amplifier with the higher damping factor can better control the speaker systems, and all other things being equal (frequency response, phase shift, distortion, etc.) that it is a better amplifier."

And,

"The bottom line is, a really low damping factor can tell you an amp isn't going to be all that great with a highly reactive speaker (the larger a speaker driver is physically, and the more power it is designed to handle, the more likely it is to be highly reactive.) What's really low? Well, if we're talking about 8 ohm speakers, a damping factor below about 30 indicates it's going to have noticeably poorer control of a highly reactive load as compared to an amplifier with a damping factor of 100. How much? It works out to about 10% worse (because you have to factor in the speaker resistance.) As the damping factor goes lower, it gets worse yet. You can hear a 10% difference in speaker control. Trust me!"

My bottom line, take your negative attitude and piss poor info and put it were the sun doesn't shine, you CRACKPOT!

Edit on the CRACKPOT.

George Grand · March 2005

It's one word......crackpot.

Now.... rat **** is two words. Cro-Mag is hyphenated, but not two words.
Munchkincock, one word (unless of course you want to personalize it and go with MR. Munchkincock, then it would be two words).

George Grand (of the Jersey Grands)

RuSsMaN · March 2005

George,

Is 'mouth breather' one or two, or hyphenated? I just ask because I haven't had to use it in a while, and I'm getting sloppy.

Cheers,
Russ

George Grand · March 2005

One word when applied to an organism with SOME human qualities.

George Grand (of the Jersey Grands)

LINEAR DAMPING FACTOR (20-20kHz)

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