>Randawg,
>
>Speakers don't have a damping factor.

Yeah they do. Its defined by the moving mass and the voice coil's ability to control it within the given magnetic field at each frequency.

>Amplifiers do, and it
>is simply a ratio of the load impedance of the driver
>divided by the output impedance of the amp.

Ok, if I do agree with that, the impedance of the driver changes per frequency; therefore, it is not a simple calculation. Furthermore, output impedence of an amp is only relevant to the current and not the voltage across it. So you will need to know the voltage and current constraints of the amp in order to compute the wattage and dampening ability. Some amps have 'high voltage'/'high current' modes controlled by a switch somewhere. When I built amps, I always used a very high (10,000 to 100,000 ohm) resistor on the inputs. This eliminates pretty much all of the current and leaves all the voltage. Same applies to the output resistence, current don't pass over resistors very easy, voltage does. Ever wonder why 8 ohm speakers sound better?

As a matter of fact, you can even say the speaker wire has dampening factors. Especially so if all it were was to divide some impedences. Every wire configuration has some capacitance, inductance as well as resistence (DC). You can use the equations I provided earlier to compute the impedence.

>You are correct
>that it will help determine how controlled the amplifier is
>but it has nothing to with power.

Well, that's why I put 'power' in quotes. I don't know a better word to explain it. You'll just have to get the idea.

>The output impedance
>remains the same regardless of how much power is provided.

Voltage Current dependent, see above.

>On the driver itself, heat can effect the impedance of the
>driver, which will effect the DF when measured across the
>terminals of the driver.

Yep, so can humidity and age.

>This is where the real world
>really destroys the merit of a high DF amp. Just run the
>numbers and include the series resistance of the typical
>speaker wire into the output impedance of the amp, and you
>will see that anything over 100 (high estimate) will have
>little to no effect.

Don't forget the reactances of the wire and the ability of the voice coil to control the moving mass in the given magnetic field.

>
>So lets eliminate DF as an issue in 99.999% of car audio
>amps. Even a poor quality amp will have a DF close to 100.
>Even marginal quality amps will make it pretty much
>irrelevant.

What do you suggest is the problem then? Some reason the whole industry is sold on the Df idea.

>
>Be back later....gotta go.
>
>I will bring back up from Manville Smith, RC, DN, Dan
>Wiggins, David Hyre, Nick McKinney, Thilo and hopefully
>others when I return.

Oh boy, I'm off to bed, I guess class resumes in the morning.

 

[updated:LAST EDITED ON 08-Jan-03 AT 09:53 PM (EST)]>>dnewma04 your wrong. a speaker can be blown running too
>>little of power. we already discussed this earlier and an
>>audio technician stepped in. take a look at the bottom of
>>this thread.
>>https://www.ford-trucks.com/dcforum/DCForumID96/596.html
>>randawg you are right. you get a star
>
>Well Damn, I guess I am wrong since rbrendel said so. I
>stand corrected...
>
>seriously, that link almost backs up my point.
>
>If you don't have anything to bring, don't bring it.
>Randawg and I were actually backing up what we were saying,
>try to do the same.

ooo now i know what your saying, you want me to back it up through technical explanation. like i said i was an installer for a summer not an audio engineer.(still in highschool) im just sharing what i was told by kicker and the thread that backed up my answer. i guess your mad because i just stated the solution flat out with no explanation thinking that i was completely right. well im wrong if the audio technicians are wrong. if your so sure your right why dont you share your theory with an expert so we can all get this straight? but im confused. do you still think a speaker cannot be damaged by too little power? thats the bottom line question here, nothing more nothing less. you are a smart guy being able to talk technically like that but its not proving anything. i just answered the bottom line question, thats it, if you dont like it flame the experts. im sorry if i cramped your style, ill shutup and let you prove why your right.

 

[updated:LAST EDITED ON 09-Jan-03 AT 08:58 AM (EST)]Randawg,

I'll try to clear this up as much as I can with the limited time I have.

DF=Damping factor. It is a ratio, that is all. It is not a complex calculation even thought the load impedance will vary.

The term damping is used in other audio components, for instance a enclosure can be overdamped and underdamped. Speakers have mechanical and electrical damping and the combination of the two gives the overall damping. Now, I have never heard that referred to as a "Damping Factor" but I understand where you are coming from.

Speaker wires do not have a DF, but they do have resistance.

Crossover components do not have a DF but they do have resistance.

That being said, any resistance added between the amplifier and the speaker will be added to the output impedance of the amp.

Lets use a quick example. I had a PPI A600 that had a DF of >400 so we will just use 400 in our example.

DF=Load Impedance/Output Impedance
400=4/Output Impedance
Output Impedance = .01

Simple math so I think I can safely say we agree here, right?

Well, this is measured across the terminals of the amp. When you add the effect of series resistance in wiring to the mix, the real world output impedance (at the speaker terminals) will include this. So now our nice little DF of 400 will drop.

DF=4 ohms/(output impedance+series resistance)
DF=4 ohms /(.01 ohms + .2 ohms) (conservatively)
DF=19

If we were to use a DF of 80 for our initial spec of the amplifier we get the following.

DF=4 ohms/.25
DF=16

This is the reason why I said that DF can virtually be eliminated as a cause of a speaker blowing. Any even marginal amp will provide enough control over the speaker to eliminate DF.

We already established that turning down the volume control will not make speakers blow, so we have determined that too little power will not cause a driver to blow.

Here is a quote from Richard Clark---

"gee guys-------this has to be about the 2 millionth time i have tried to cover this subject-----a search in the archives will provide some good info from when i had a little more time to actually cover this dead horse----- but to cover what rob has already well explained-------it is another one of those voodoo beliefs that will always haunt the audio world that underpowering a speaker has any negative effects EXCEPT for the simple fact that if the speaker is underpowered it will not play as loud--------what happens if we underpower a race car??????----it does not go as fast-------does it cause the car to crash???--i think not-------what happens if we underpower our toaster?????-----the toast does not get as dark-----there are idiots that would have us believe that the toast would be burned-------imagine trying to explain that to your family-----gee i turned the thermostat on the toaster down and it burned the toast------are we forgetting that wattage is a measure of power and in electronics power is directly related to HEAT and it is HEAT that BURNS up voice coils ------ underpower a 200 watt speaker with a 10 watt amp and what happens???????the speaker will play about 10 dB less loud and distort if you try to play it any louder than a 10 watt amp will drive it--------will it hurt the speaker?????------lets look at the facts and forget the pleadings of the technically ignorant-------that 10 watt amp when driven into total clipping will likely put out about 20 watts of really distorted audio-------and that 200 watt speaker will just lap it up like a thirsty dog and last nearly forever till the sunlight rots its cone out or you can afford a larger amp---------there are only two kinds of people that believe underpowering a speaker is damaging------the technically uninformed or the totally ignorant------which one are you????????............RC"


That summed it up rather effectively. If my volume control argument had not.

I will post many many more quotes from "industry" leaders if you wish.

 

Go to http://www.gr-research.com/dodd_amp.htm and search for the word "dampening". Read that.

Then read this http://www.loudspeakers.net/technote/dampfact.html

Then these:
http://www.studio-systems.com/audiofeatures/novdec99/dampingFactor/damp01.htm
http://www.crownaudio.com/pdf/amps/damping%20factor.pdf
http://www.trueaudio.com/post_013.htm
http://www.classic-audio.com/marantz/mdampingfactor.html

What you guys fail to understand is I have seen this happen many times. What? You think I don't have any test equipment? I have a an oscilloscope, RTA, DVM, and SPL meter and I USE them. I have tons of software, LEAP, WinISD, PerfectBox, BoxPlot, BlauBox, BandBox, Peerless, WinSpk, WinSub, you name it and I USE them. I am telling you, what I have told you, I blew a sub with too little power, and have yet to see one blow (unintentionally) from too much power! You must have an amp that can sufficiently control the moving mass presented by the driver. You must have a voice coil that can sufficiently control the moving mass inside the magnetic field. And all this is frequency dependent. Not to mention the dampening effects presented by the enclosure.

>DF=Damping factor. It is a ratio, that is all. It is not a
>complex calculation even thought the load impedance will
>vary.

The computation will vary according to the impedance presented by the driver, which will vary according to frequency. Therefore, it is not a 'simple' computation. Also, the wire used will present varying reactances; therefore, varying impedances. Even if they are small.

>The term damping is used in other audio components, for
>instance a enclosure can be overdamped and underdamped.

The word dampen/damp means to deaden or stifle something (look it up). Therefore, an ability to slow and stop a moving mass would be refered to as a dampening/damping ability.

>Speakers have mechanical and electrical damping and the
>combination of the two gives the overall damping.

Apparently so.

>Now, I
>have never heard that referred to as a "Damping Factor" but
>I understand where you are coming from.

I have, but glad to hear it.

>Speaker wires do not have a DF, but they do have resistance.

Wires (assuming multistrand - what else?) have what is called reactances.
Reactance is defined as the opposition to the flow of alternating current caused by the inductance and capacitance in a circuit, measured in ohms. The total opposition to the flow of current in the circuit is the impedance, which is the sum of the reactance and the resistance in the circuit. Symbol is X.

Therefore,
Xc=1/(2*PI*F*C) where C is Farads, F is frequency, PI=3.14159265358979....
Xl=2*PI*F*L where L is in Henrys
R=resistence in ohms, Xc in ohms, Xl in ohms
Z=Xc+Xl+R, Z = impedance in ohms

Wires do have capacitance, inductance, and resistance and these can be taken into account as they will present a load at varied frequencies.

>Crossover components do not have a DF but they do have
>resistance.

They affect the ability of the amp to control the driver; therefore they can dampen. As a matter of fact, x-overs dampen quite well, that's why we use them.

>That being said,

That being said, you have stuck your foot in your mouth once again.

>any resistance added between the amplifier
>and the speaker will be added to the output impedance of the
>amp.

Any impedance... lets use proper terms. Otherwise, yes.

>Lets use a quick example. I had a PPI A600 that had a DF of
>>400 so we will just use 400 in our example.

400??? At what frequency?

>DF=Load Impedance/Output Impedance
>400=4/Output Impedance
>Output Impedance = .01

Nope, you can't say 4ohms. DC resistance has nothing to do with it. Impedance is what we are concerned with.

>Simple math so I think I can safely say we agree here,
>right?

NO. Not too simple, Being the math wiz that I am, even I would need a spreadsheet at the least.

>Well, this is measured across the terminals of the amp.
>When you add the effect of series resistance in wiring to
>the mix, the real world output impedance (at the speaker
>terminals) will include this. So now our nice little DF of
>400 will drop.

>DF=4 ohms/(output impedance+series resistance)
>DF=4 ohms /(.01 ohms + .2 ohms) (conservatively)
>DF=19
>
>If we were to use a DF of 80 for our initial spec of the
>amplifier we get the following.
>
>DF=4 ohms/.25
>DF=16
>
>This is the reason why I said that DF can virtually be
>eliminated as a cause of a speaker blowing. Any even
>marginal amp will provide enough control over the speaker to
>eliminate DF.

But it don't work that way in the real world.

>We already established that turning down the volume control
>will not make speakers blow, so we have determined that too
>little power will not cause a driver to blow.

That's an absurd arguement, turning the volume down has nothing to do with nothing. Turning it up is where we are concerned. Turning it down only gives the amp better control as it has a higher overhead before reaching max capabilities of the transitors. Remember, I never said I blew a speaker at low volume and that is not the arguement. It's when we decide to turn it up that trouble comes. And if your near the max capabilities of the amp, your risk for damage increases exponentially.

>Here is a quote from Richard Clark---
>snip<
>what happens if we underpower a race car??????----it does not go
>as fast-------does it cause the car to crash???--

I'm surprised at him, very surprised. This is a sorry example, cars are not required to oscillate back n forth, but let's use this no less. If you underpower a car, you will destroy the engine much faster than if you had the optimal amount of power. This is common sense here. If you stick a 1.5 liter engine in my truck (7600lbs), that engine could be toast before I could get across town. And yes, I might get hit because I couldn't get going in the intersection before the light changed. To really make this clear, you have to dumb down the brakes as well, so my truck could only stop as fast as it could accelerate. This way, it is more like a speaker, it can accelerate in both directions equally. Thus, with weaker brakes, anybody should see the risks. It's all about how to control the moving mass.

what happens if we underpower our
>toaster?????-----

Now dude has gone off the deepend. I think he's toasting hash or something. There's nothing about a toaster that can be compared to a speaker. You guys need to stop blindly following any concept you hear and start questioning things more.

>it is HEAT that BURNS up voice coils

Well, I agree here. When a sub pushes a cone out and doesn't bring it back before being told to push it out again, it will get hot.

>------ underpower a 200 watt speaker with a 10 watt amp and
>what happens???????

As long as you don't overdrive the amp, nothing. If you do, probably nothing still. But try that with a 200 watt amp and 300 watt sub. The 200 watts are enough to do damage, 10 is not. 10 watts may do damage to a smaller speaker, like an almost 0 xmax paper cone radioshack 3 inch model.

>lets look at the facts and forget the
>pleadings of the technically ignorant-------that 10 watt amp
>when driven into total clipping will likely put out about 20
>watts of really distorted audio-------and that 200 watt
>speaker will just lap it up like a thirsty dog and last
>nearly forever till the sunlight rots its cone out or you
>can afford a larger amp

That's the first bit of truth he has said so far.

>there are only two kinds of
>people that believe underpowering a speaker is
>damaging------the technically uninformed or the totally
>ignorant------which one are you????????............RC"

I have a Bachelor of Science degree in Industrial Engineering. I received the Governors Honors award in mathematics from the governor of Georgia, Joe Frank Harris, in 1989. I finished 2 quarters (28hrs) of college before I graduated high school. Without giving you a bio of my entire life, let's just say, I am neither "technically uninformed nor totally ignorant". Since then I have participated in numerous audio experiments. Where I have constructed atleast one of, what seems to be, every kind of enclosure imaginable. I have studied and built folded horns, both front and back loaded, transmission lines, isobars, "wicked ones", WO32's, "death boxes" and "house wreckers" and various combinations just to see. I have built amplifiers, crossovers, phase shifters, delays, and numerous other YABB's I have no use for. I have had 8 courses in calculus and higher mathematics, 5 courses in physics, and 4 courses in electronics. I have all my books on the shelf not more than 4 feet from me and I still use all of them. I understand the workings of acoustic suspension and sound propagation as well as you understand how to ****. So I am here to tell you, that both YOU and RC are wrong!

About 8yrs ago, I read everything Richard had to say, I thought he was the shiz-zit. However, I have moved on since and have come to a greater understanding than where I began. Although, last I read, I do remember always agreeing with him. Be that as it may, I've lost some respect for him now, and will re-think my recommended reading material. With analogies like he is proposing, who knows what other errors in analysis he may have?

>That summed it up rather effectively. If my volume control
>argument had not.

Both arguements are bunk. Should be easy for any reasonably intelligent person to recognize that, if they weren't first persuaded into being led blindly.

>I will post many many more quotes from "industry" leaders if
>you wish.

Please do, fill up the entire page. I would like to know whom to avoid.
You should have typed "leaders" in quotes as well.

BTW, Bert Doppenberg at Lowther http://www.lowther-america.com/ (arguably the best drivers made-definitely the fastest with a response of 30-22kHz) in a forum at harvard.edu said, "It depends on what you are looking for. The rather large surface of a horn needs control if you want to have true accurate, short (fast) and "kicking" bass. I experimented with several amps and found out that using an amp with a higher dampening factor gives a better detailed, more dynamic, more ease and kicking bass coming from my horns or other large coned systems."

 

Well,

First of all, thanks for the biography. I'm thoroughly impressed that you have a degree.

I will be back in a day or so, I have some personal issues to take care of.

 

>I have a Bachelor of Science degree in Industrial
>Engineering. I received the Governors Honors award in
>mathematics from the governor of Georgia, Joe Frank Harris,
>in 1989. I finished 2 quarters (28hrs) of college before I
>graduated high school. Without giving you a bio of my
>entire life, let's just say, I am neither "technically
>uninformed nor totally ignorant". Since then I have
>participated in numerous audio experiments. Where I have
>constructed atleast one of, what seems to be, every kind of
>enclosure imaginable. I have studied and built folded
>horns, both front and back loaded, transmission lines,
>isobars, "wicked ones", WO32's, "death boxes" and "house
>wreckers" and various combinations just to see. I have
>built amplifiers, crossovers, phase shifters, delays, and
>numerous other YABB's I have no use for. I have had 8
>courses in calculus and higher mathematics, 5 courses in
>physics, and 4 courses in electronics. I have all my books
>on the shelf not more than 4 feet from me and I still use
>all of them. I understand the workings of acoustic
>suspension and sound propagation as well as you understand
>how to ****. So I am here to tell you, that both YOU and RC
>are wrong!
>

Yeah? I have watched nearly every porno ever made. I was permanently banned from Source Adult Video because I rented so much **** in a week it frightened the people that worked there. Without giving you a bio of my entire life, let's just say I'm neither "normal, nor right in the head". Since then I have participated in several sexual experiments. Where I have constructed at least one of, what seems to be, every kind of mechanical sex devices imaginable. I have studied and built jelly ding dongs, mechanical hoo-hoos, "jackhammers", Mr. Perfections, "two random orbit sanders built into a couch" and "home wreckers" and various combinations just to see. I have build leather dong suits, body stretchers, vibrating beds, and neumerous other toys I have no further use for since I got caught in my zipper real bad. I have watched all the pornos, been to strip clubs, got me many a hoe, and had intercourse with 4 electronic robots. I have my entire sticky stack of **** on a shelf not 4 feet from me and I still use up all of them.

So that must mean I am a sexual genious then right? I must know everything because I dun read it.

Oh yeah, and you seem very upset for some reason... take your medication!

 

Addressing RanDawg:

It's very simple, largely because a speaker is such a simple device.
It's a coil of wire suspended in a magnetic gap.
"Blowing a speaker" can take two forms, right?
Either you bottomed the subwoofer out due to overexcursion (which can happen below the RMS power rating, due to many factors), and critically damaged it...
Or you overheated the voice coil itself, causing it to melt, or causing the lamination to release and scrape.
Both are very apparent when you decone the subwoofer, as to which type of damage occurred.

With all other factors being correct -
And by that I mean the subwoofer is in a proper size/type enclosure, and you are playing material appropriate for that size/type enclosure/subwoofer combination, and your amp's gains are set so they do not clip (reasonably anyways, a bit of clipping is actually quite common and relatively harmless)
- then you cannot harm a subwoofer by putting too little power to it.

The analogy of the volume **** is very appropriate.
As you turn the volume down, your amplifier puts progressively less and less power to your subwoofer, until you have the volume all the way off, at which point you won't have any power going to the subwoofer.
It's exactly the same thing as if saying "If you don't run your subwoofer at full volume all the time, you will damage it"
There's no disputing this.


Now, let's look at what really could have happened, which you failed to correctly identify:

If you put a subwoofer in a high-tuned ported box (or something equivalent.. free air, aperiodic, etc..), and played subsonic tones through the subwoofer, you can very easily bottom it and damage it with well under the power it is rated for.
The problem in this case is NOT that you "had too little power going through it", that's NOT what damaged it. More power would have damaged it worse. Even less power would have saved it.
The problem in this case was that you built the wrong type of enclosure and/or selected the wrong subwoofer for the material you wished to play on it.

If you put the subwoofer in a correct size/type enclosure (for the material you were presenting to it), but had some gain control somewhere set too high in your signal chain, you could be clipping the subwoofer. Small amounts of clipping won't even hurt too much. But as you begin to present the subwoofer with square-wave like, obnoxiously clipped signals, things are different, as you aren't feeding the subwoofer current that is progressively changing phase angle (which the subwoofer mimics by progressively changing cone motion direction and velocity - that is, it goes in and out, fastest as it passes the "at rest" position, slowest as it reaches it's excursion limit)...
The signal you are feeding the subwoofer in this case is one that it can't hope to accurately translate into cone motion...
And I am sure it has been presented here before that the actual RMS power output from the amp increases from the real RMS rating.. does that count as overpowering?
Could you know for sure this wasn't the case?

Taking a look at the deconed unit would tell the whole story, just like spark plugs tell the whole story when tuning your truck..
Exactly the same...

But like I said before, all other factors being correct, you cannot damage a subwoofer by having too little power.
It IS physically impossible.

>
>What you guys fail to understand is I have seen this happen
>many times.

I don't doubt you may have seen a woofer reach possibly it's mechanical limits on less power than it is rated at... even unclipped power. That's a function of the relationship between the driver and the enclosure it is in, and the material you play with it.

I don't even doubt that you may have seen a woofer reach it's thermal limits on less power than it is rated at.

But the problem isn't BECAUSE the driver was getting less power than it was rated for.
You have witnessed problems DESPITE the driver getting less power than it is rated for.

It doesn't take Einstein to realize that you have at least one of several things going against you:
1) a complete lack of analytical skills - much less the advanced skills it would take to reach a scientific conclusion.
2) a big mouth, coupled with a lack of integrity, shamelessly (yet obviously) trying to operate like the Wizard of Oz.
3) a paper education.. gone through school learning retention skills, but not learned to truly think. The sort of education that breeds trivia, not thought processes.

>I have a Bachelor of Science degree in Industrial
>Engineering. I received the Governors Honors award in
>mathematics from the governor of Georgia, Joe Frank Harris,
>in 1989. I finished 2 quarters (28hrs) of college before I
>graduated high school. Without giving you a bio of my
>entire life, let's just say, I am neither "technically
>uninformed nor totally ignorant".
> ...I have had 8
>courses in calculus and higher mathematics, 5 courses in
>physics, and 4 courses in electronics. I have all my books
>on the shelf not more than 4 feet from me and I still use
>all of them.

Shallow shallow shallow..
Paper does not indicate thought process skill.
Mensa does not reward even prestigious degrees.
After all, you are measured for memory retention in schools, not for thought process - Particularly in the field of mathematics (odd you would bring that rather rigid and well defined field up.. my mother is a math professor, interestingly... if you feel people must have qualifications for all words spoken )

And look at you bragging... it's laughable.
No man who had truly had such accomplishments and financial cushioning to support such education and equipment would be so lacking in ego that they felt they had to stress how qualified they were in terms of things they owned, and paper certificates...
Rather than being able to prove their worth by displaying knowledge.
I'm sorry, I find that very sad!

I am sure I am not the only one throwing the BS flag on most of your claims.

I have been in the industry for over ten years, after opening my first humble installation business to earn a few bucks to support a very expensive hobby through the college years.

Today, I am co-founder of a very new, very high end manufacturing company, set to release our first products in the next two months (www.betteraudio.com).

I feel that I could blow holes in your claims left and right.
I too have many of the software packages you claim to own... many of them have been lost to many "Format C:"s of the past however... I certainly don't use them all anymore. Why would I?
For example, if you have LEAP (indisputably the most complete and industry-accepted standards for enclosure design and analysis), why would you still "USE" BlauBox, WinSub, WinSpk, BandBox, etc?

I don't even want to get off on a tangent though...
Let's focus on the claim being made here.


>About 8yrs ago, I read everything Richard had to say, I
>thought he was the shiz-zit. However, I have moved on since
>and have come to a greater understanding than where I began.
> Although, last I read, I do remember always agreeing with
>him. Be that as it may, I've lost some respect for him now,
>and will re-think my recommended reading material.

Interesting that you have eclipsed Richard's knowledge of acoustics and acoustical electronics, despite his various industry involvements and industry ownerships, his nearly unlimited budget and collection of equipment to use - which he obviously REALLY does use... not to mention his rather inherent experimentations...
With such knowledge, and financial freedoms, where is your audio company, manufacturing ventures, patents being licensed to others?
Where are your capitalizations?

>With
>analogies like he is proposing, who knows what other errors
>in analysis he may have?
>
Such a deliciously ironic statement!


Bottom line, what you claim is impossible.
Yes, you could manipulate other variables to create a scenario where a subwoofer could be critically damaged at a power level below it's RMS rating, but that is certainly not to say it was damaged BECAUSE you ran it at a power level below it's RMS rating...
It was damaged because of the other variables that were manipulated incorrectly...
And that's all there is to it, period.

 

Alright, I had to register for the sole purpose of responding here, because this is plain insane.

RanDawg, you are wrong.

dnewma04, you are right.

Ran, I commend your arguments, they are well thought out, but you just don't seem to have a firm grip on it all yet. I'm not flaming, I'm not trying to cause trouble, just trying to help.


"Underpowering" a driver of any type is not going to kill it. I believe dnewman's first question says it all

"When you turn down your volume control, do your speakers blow?"

We have already established the answer: "No" On that point I believe we can all agree, right? Ok. Moving on.

However, Ran, you state it is a good idea use amps capable of producing more power than your particular driver is rated to take. Very true. I am a FIRM believer in that as well. But, you're missing a few components to that fact.

Now, why is this, some of you may be asking? I'll tell ya. :-) We shall compare and amp pusing 300 watts and one pushing 600 watts. Of course, we'll also assume both of those ratings are for clean, RMS power, not peak, or highly distored. Ok? Good. Say you deliver a sub 300 watts, the amp that will only do 300 rms is performing at its highest level, therefore working harder, which equates to more heat, which equates to and increse in THD and greater chance of failure, among other things.

Now when that 600 watter is pushing 300 watts, it is obvisouly NOT working near as hard as the 300 watt amp. This gives you a thing called HEADROOM.

Remember this my friends:
HEADROOM IS YOUR BEST FRIEND!

Now that we have covered the BASIC premise on this theory of operation, we can move on.

Now, it has been stated that giving a driver less power than rated will blow it. Completely WRONG! Giving it less power than it can handle only limits its performance, and there is even more variables there as well. Mainly, box type and size.

The power rating given on drivers is one of THERMAL limits, no mechanical. That fact, while doesnt pertain exactly to this thread, is still important.

Mechanical power handling, on the otehr side, is COMPLETELY box dependent. A sub rated at 600 watts could very well take 1200 watts in a small sealed enclosure, while in a large ported or bandpass, it may only take 150 watts before it fails.

NOW HEAR ME ON THIS! THIS IS ONLY MECHANCIAL LIMITS! Don't try giving twice the rated power to your average sub because it can not take it thermally. You will melt the Voicecoil, which is just not good for anybody.

Moving on.

Randawg, you are seeing subs blow on amps below the rated power capabilities of the sub. Very true. It happens all the time! But it doesnt happen because there isn't enough power. It happens because there is too much power.

Whoa, did I say that? Weird.

Let me explain.

Even a small amp can produce much more power than it is rated, but it will be severly CLIPPED power. That is what is killing a sub. When you start sending severely clipped signals to drivers, they just don't live. The power of a clipped signal is intense, as the clipping increases, the power increases expontially.

So, when people buy theis little amps to push subs that need a lot of power to get them moving, they (the owners) crank the grain, crank the bass boosts where-ever possible, and send massively clipped signal to the sub.

Are you guys following me?

Just ask if I need to explain anything, I'm more than happy to help.

And don't see my post count of one and assume I know nothing. Head on over the www.caraudioforum.com/vbb2 . I am well know and respected over there.

Peace all!
Mike Maze

 

yep geo's right.

my first system was two type R's with an rms of 300 watts getting 230 watts each. i had them in both sealed and ported. i set the gains myself (which was also my first time setting gains). had them for a year and they were perfectly fine till they go jacked. then had two 3515's with an rms of 800 watts getting 750 watts each. played fine for months until i sold them.

why didnt either pair blow? they were in decent enclosures and the amp wasnt clipping. underpowering doesnt kill subs...user error kills subs.

 

>Addressing RanDawg:
>
>It's very simple, largely because a speaker is such a simple
>device.
>It's a coil of wire suspended in a magnetic gap.
>"Blowing a speaker" can take two forms, right?
>Either you bottomed the subwoofer out due to overexcursion
>(which can happen below the RMS power rating, due to many
>factors), and critically damaged it...
>Or you overheated the voice coil itself, causing it to melt,
>or causing the lamination to release and scrape.
>Both are very apparent when you decone the subwoofer, as to
>which type of damage occurred.
>
>With all other factors being correct -
>And by that I mean the subwoofer is in a proper size/type
>enclosure, and you are playing material appropriate for that
>size/type enclosure/subwoofer combination, and your amp's
>gains are set so they do not clip (reasonably anyways, a bit
>of clipping is actually quite common and relatively
>harmless)
> - then you cannot harm a subwoofer by putting too little
>power to it.

You can if the amp is near its max capabilities, yes.

>The analogy of the volume **** is very appropriate.
>As you turn the volume down, your amplifier puts
>progressively less and less power to your subwoofer, until
>you have the volume all the way off, at which point you
>won't have any power going to the subwoofer.
>It's exactly the same thing as if saying "If you don't run
>your subwoofer at full volume all the time, you will damage
>it"
>There's no disputing this.

This arguement is absurd! When the volume is down, there is sufficient headroom and the amp is not near max capabilities.

>Now, let's look at what really could have happened, which
>you failed to correctly identify:
>
>If you put a subwoofer in a high-tuned ported box (or
>something equivalent.. free air, aperiodic, etc..), and
>played subsonic tones through the subwoofer, you can very
>easily bottom it and damage it with well under the power it
>is rated for.
>The problem in this case is NOT that you "had too little
>power going through it", that's NOT what damaged it. More
>power would have damaged it worse. Even less power would
>have saved it.
>The problem in this case was that you built the wrong type
>of enclosure and/or selected the wrong subwoofer for the
>material you wished to play on it.

How do you know so much about the enclosure I built? Furthermore, I had 29Hz port frequency at the time in question. I am fully aware of possible damage from subsonic tones. And if more power would have damage it more, why do I now have twice the power and have not blown a sub in 6yrs? This arguement is bunk! Less power? What, 10 watts? Yeah, that would have saved it, but that's not a practical solution.

>
>If you put the subwoofer in a correct size/type enclosure
>(for the material you were presenting to it), but had some
>gain control somewhere set too high in your signal chain,
>you could be clipping the subwoofer.

Once again you have no idea what you are talking about. I have posted here before about how to correctly set gains with an o-scope and I very well know how to do it.

Small amounts of
>clipping won't even hurt too much. But as you begin to
>present the subwoofer with square-wave like, obnoxiously
>clipped signals, things are different, as you aren't feeding
>the subwoofer current that is progressively changing phase
>angle (which the subwoofer mimics by progressively changing
>cone motion direction and velocity - that is, it goes in and
>out, fastest as it passes the "at rest" position, slowest as
>it reaches it's excursion limit)...

Like I said over n over, it wasn't clipping. Go read.

>The signal you are feeding the subwoofer in this case is one
>that it can't hope to accurately translate into cone
>motion...
>And I am sure it has been presented here before that the
>actual RMS power output from the amp increases from the real
>RMS rating.. does that count as overpowering?

Yes, it does.

>Could you know for sure this wasn't the case?

What, was the amp overpowered? Isn't that obvious? Of course it was, or atleast near its max capabilities.

>Taking a look at the deconed unit would tell the whole
>story, just like spark plugs tell the whole story when
>tuning your truck..
>Exactly the same...

Didn't want to void the warranty, just took it in and got another.

>
>But like I said before, all other factors being correct, you
>cannot damage a subwoofer by having too little power.
>It IS physically impossible.

It is very possible, you are up against the world with this.

http://www.blaupunktusa.com/speakers/speakers_faqs.html
http://www.jblpro.com/pub/technote/lowpower.pdf
http://www.mbquart.com/ha-techpapers.htm
http://www.crutchfield.com/S-h9PZf3vjdml/tech/kb303.html
http://www.caraudiogalaxy.com/caraudio_rmspower.htm

Until you can convince the audio engineering establishment, you'll have no hope with me (even though I may not agree with their reasoning).

>>What you guys fail to understand is I have seen this happen
>>many times.
>
>I don't doubt you may have seen a woofer reach possibly it's
>mechanical limits on less power than it is rated at... even
>unclipped power. That's a function of the relationship
>between the driver and the enclosure it is in, and the
>material you play with it.
>
>I don't even doubt that you may have seen a woofer reach
>it's thermal limits on less power than it is rated at.

The #1 reason for speaker failure is due to underpowering. This is well documented at the links I posted above and in my own experience.

>But the problem isn't BECAUSE the driver was getting less
>power than it was rated for.
>You have witnessed problems DESPITE the driver getting less
>power than it is rated for.

The problem is pushing the amp too far and having a sub with an inefficient motor structure and a heavy mass to move.

>
>It doesn't take Einstein to realize that you have at least
>one of several things going against you:
>1) a complete lack of analytical skills - much less the
>advanced skills it would take to reach a scientific
>conclusion.

Oh really, I don't get awarded for lacking analytical skills.

>2) a big mouth, coupled with a lack of integrity,
>shamelessly (yet obviously) trying to operate like the
>Wizard of Oz.

oh boy

>3) a paper education.. gone through school learning
>retention skills, but not learned to truly think. The sort
>of education that breeds trivia, not thought processes.

I have both.

>>I have a Bachelor of Science degree in Industrial
>>Engineering. I received the Governors Honors award in
>>mathematics from the governor of Georgia, Joe Frank Harris,
>>in 1989. I finished 2 quarters (28hrs) of college before I
>>graduated high school. Without giving you a bio of my
>>entire life, let's just say, I am neither "technically
>>uninformed nor totally ignorant".
>> ...I have had 8
>>courses in calculus and higher mathematics, 5 courses in
>>physics, and 4 courses in electronics. I have all my books
>>on the shelf not more than 4 feet from me and I still use
>>all of them.

This shows I am not technically challenged or totally ignorant, whatever your opinion may be. And if I am to go up against the likes of Richard Clark, a little background is in order. You're just jealous that you cannot make similar claims.

>Shallow shallow shallow..
>Paper does not indicate thought process skill.
>Mensa does not reward even prestigious degrees.

Yeah, I forgot to mention mensa.

>After all, you are measured for memory retention in schools,
>not for thought process - Particularly in the field of
>mathematics (odd you would bring that rather rigid and well
>defined field up.. my mother is a math professor,
>interestingly... if you feel people must have qualifications
>for all words spoken )

My memory has nothing nothing to do with it, its the understanding that counts. Equations can always be rediscovered through concept realization or simply looked up. Understanding cannot be looked up.

>And look at you bragging... it's laughable.
>No man who had truly had such accomplishments and financial
>cushioning to support such education and equipment would be
>so lacking in ego that they felt they had to stress how
>qualified they were in terms of things they owned, and paper
>certificates...

If i were bragging, I would have done that sooner. You posted RC, and his qualifications are well recognized, but mine are not. If I were bragging, I could do more.

>Rather than being able to prove their worth by displaying
>knowledge.

Displacing knowledge does not seem to matter to the likes of you. You spout this nonsense like common sense and my continually lecturing is not sinking in. Its like you are not reading what I'm saying.

>I am sure I am not the only one throwing the BS flag on most
>of your claims.

That's fine by me, I don't need to prove anything. I stated my qualifications, and let it stand on its own merit. Ask me a decent question to determine my true aptitude.
>
>I have been in the industry for over ten years, after
>opening my first humble installation business to earn a few
>bucks to support a very expensive hobby through the college
>years.
>
>Today, I am co-founder of a very new, very high end
>manufacturing company, set to release our first products in
>the next two months (www.betteraudio.com).

Good for you, very glad to hear you are surviving this economy.

>I feel that I could blow holes in your claims left and
>right.

I don't think so.

>I too have many of the software packages you claim to own...
>many of them have been lost to many "Format C:"s of the past
>however... I certainly don't use them all anymore. Why
>would I?

Oh, I have them.

>For example, if you have LEAP (indisputably the most
>complete and industry-accepted standards for enclosure
>design and analysis), why would you still "USE" BlauBox,
>WinSub, WinSpk, BandBox, etc?

I use LEAP, WinISD, perfectbox mostly. LEAP is complicated if I don't have all the parameters and have to guess. WinISD has a nice graphical interface for quick adjustments of volumes and ports. Perfectbox gives a simplistic view w/o having to enter in a lot of values. They each have their attributes, but yes, LEAP is the best. I have said that here before. However, I have used all of those mentioned through the years.

>
>>About 8yrs ago, I read everything Richard had to say, I
>>thought he was the shiz-zit. However, I have moved on since
>>and have come to a greater understanding than where I began.
>> Although, last I read, I do remember always agreeing with
>>him. Be that as it may, I've lost some respect for him now,
>>and will re-think my recommended reading material.
>
>Interesting that you have eclipsed Richard's knowledge of
>acoustics and acoustical electronics, despite his various
>industry involvements and industry ownerships, his nearly
>unlimited budget and collection of equipment to use - which
>he obviously REALLY does use... not to mention his rather
>inherent experimentations...
>With such knowledge, and financial freedoms, where is your
>audio company, manufacturing ventures, patents being
>licensed to others?
>Where are your capitalizations?

Yes, I felt I had absorbed all I could from his and sought more than he had to offer. Actually, I'm not quite sure what he has innovated since 1996. However, I have gone on to study hone loaded enclosures and various designs I develop on my own. These I don't remember RC talking much about, if any. I'm not applying for patents. Why would I? Nothing really new. No, I don't have an unlimited budget, no financial backers, and no manufacturing ventures. Just an engineer that pursued good sound for years.

>
>>With
>>analogies like he is proposing, who knows what other errors
>>in analysis he may have?
>>
>Such a deliciously ironic statement!

Glad you like it. It's true.

>Bottom line, what you claim is impossible.

My claim is mathematically and physically sound.

>Yes, you could manipulate other variables to create a
>scenario where a subwoofer could be critically damaged at a
>power level below it's RMS rating, but that is certainly not
>to say it was damaged BECAUSE you ran it at a power level
>below it's RMS rating...

A driver with a high power rating is typically inefficient and is very likely to have a large moving mass. period. Therefore, you cannot effectively control this driver with a weak amp when driving that amp near its max capabilities.

>It was damaged because of the other variables that were
>manipulated incorrectly...

Not at all.

>And that's all there is to it, period.

There is more to it than you realise.

 

>Alright, I had to register for the sole purpose of
>responding here, because this is plain insane.

I figure you all did so.

>RanDawg, you are wrong.

I am right.

>Ran, I commend your arguments, they are well thought out,
>but you just don't seem to have a firm grip on it all yet.
>I'm not flaming, I'm not trying to cause trouble, just
>trying to help.

Your commendation is regarded. However, my grip is firm.

>"Underpowering" a driver of any type is not going to kill
>it. I believe dnewman's first question says it all

Underpowering is the #1 reason drivers are return to place of manufacture.

>"When you turn down your volume control, do your speakers
>blow?"

This arguement is absurd! Do you guys read my posts or not? I have commented on this several times. Get it together.

>We have already established the answer: "No" On that point I
>believe we can all agree, right? Ok. Moving on.

No, we have not established this.

>However, Ran, you state it is a good idea use amps capable
>of producing more power than your particular driver is rated
>to take. Very true. I am a FIRM believer in that as well.
>But, you're missing a few components to that fact.

What's your beef then?

>Now, why is this, some of you may be asking? I'll tell ya.
>:-) We shall compare and amp pusing 300 watts and one
>pushing 600 watts. Of course, we'll also assume both of
>those ratings are for clean, RMS power, not peak, or highly
>distored. Ok? Good. Say you deliver a sub 300 watts, the amp
>that will only do 300 rms is performing at its highest
>level, therefore working harder, which equates to more heat,
>which equates to and increse in THD and greater chance of
>failure, among other things.
>
>Now when that 600 watter is pushing 300 watts, it is
>obvisouly NOT working near as hard as the 300 watt amp. This
>gives you a thing called HEADROOM.

Yeah, my arguement for the "volume being turned down" absurdity!

>
>Remember this my friends:
>HEADROOM IS YOUR BEST FRIEND!

There's something I can agree with.

>Now, it has been stated that giving a driver less power than
>rated will blow it.

CAN blow it, not will!

>Giving it less power
>than it can handle only limits its performance, and there is
>even more variables there as well. Mainly, box type and
>size.

Your forgetting the most important variables. Moving mass and efficiency.

>The power rating given on drivers is one of THERMAL limits,
>no mechanical. That fact, while doesnt pertain exactly to
>this thread, is still important.

If a driver can take lots of amps, it will likely have an inefficient motor. Additionally, if a driver can sustain high spl w/o cone deformaties, it will have a large moving mass. Therefore, it will bo more difficult to control. Why will this not click with you?

>Mechanical power handling, on the otehr side, is COMPLETELY
>box dependent.

Not true. This is also constrained by the construction of the driver's suspension system and outside air pressures or containers like cabins of cars.

A sub rated at 600 watts could very well take
>1200 watts in a small sealed enclosure, while in a large
>ported or bandpass, it may only take 150 watts before it
>fails.

It could also take a large amount at the port frequency of a vented enclosure.

>Don't
>try giving twice the rated power to your average sub because
>it can not take it thermally. You will melt the Voicecoil,
>which is just not good for anybody.

This is true.

>Randawg, you are seeing subs blow on amps below the rated
>power capabilities of the sub. Very true. It happens all the
>time! But it doesnt happen because there isn't enough power.

It happens because the power is not sufficient to control the driver effectively and, yet, is sufficient to cause damage to the driver.

>It happens because there is too much power.

Too much out of control power that is.

>Even a small amp can produce much more power than it is
>rated, but it will be severly CLIPPED power. That is what is
>killing a sub. When you start sending severely clipped
>signals to drivers, they just don't live. The power of a
>clipped signal is intense, as the clipping increases, the
>power increases expontially.

I am aware of clipped signals and Inever let my equipment clip, go read my posts.

>So, when people buy theis little amps to push subs that need
>a lot of power to get them moving, they (the owners) crank
>the grain, crank the bass boosts where-ever possible, and
>send massively clipped signal to the sub.

True enough, but not in my case

 

>yep geo's right.

No he is not.

>my first system was two type R's with an rms of 300 watts
>getting 230 watts each. i had them in both sealed and
>ported. i set the gains myself (which was also my first time
>setting gains). had them for a year and they were perfectly
>fine till they go jacked. then had two 3515's with an rms of
>800 watts getting 750 watts each. played fine for months
>until i sold them.

Very good for you.

>why didnt either pair blow? they were in decent enclosures
>and the amp wasnt clipping. underpowering doesnt kill
>subs...user error kills subs.

User error does kill subs, clipping can kill subs, and driving a sub out of control can kill a sub.

 

HonkeytonkMonkey, that's pretty good.

So, I guess when I have a question on what impedence your sees when it cycles up your , you'll be the one to ask.

But you got it, things new to you, are old to me.

 

But as much as I like sitting here dispensing lessons on remedial physics to you guys, I do have other things to do. So, if you wouldn't mind, either come up with an original idea dealing with why I am wrong, or re-evaluate the logic of your claims. I am very tired of answering the same absurd arguements over again. Just because you subscribe to the views of RC, doesn't mean you have conducted any experiments or brought forth any reasonable evidence.

 

>>Addressing RanDawg (again):

>How do you know so much about the enclosure I built?
>
I don't.. that's why I posted what I did, nothing specific.


This is an interesting little set of statements:
>
>Like I said over n over, it wasn't clipping. Go read.
>
>
>What, was the amp overpowered? Isn't that obvious? Of
>course it was, or atleast near its max capabilities.
>
>
>You can if the amp is near its max capabilities, yes.
>
>
>The problem is pushing the amp too far and having a sub with
>an inefficient motor structure and a heavy mass to move.
>
You will have to define what you mean by having an amp operating at a level that is "at or near it's max capabilities", to a degree that could damage your speakers, while "not clipping at all."

After all, it's either clean power coming out of the amp or not.
Reaching the limits, in that capacity, simply means you have reached the limits of the clean power.
Running the amp beyond those points, IS clipping the amp.

After all, if you have your gains set to max crank, but have your volume turned low on the deck, you won't have a blip of clipping...
UNTIL you turn it up to the point where your line voltage exceeds your expected input voltage, given your gain settings.

With your gains set correctly, you cannot push an amp to it's limits.
In fact, even if you do have it set to clip a bit, that won't hurt anything.
Large amounts of clippnig, that's another story.

And because you took your O-scope and measured a signal at some volume level and didn't see clipping..
That doesn't mean anything, unless your testing variables were set correctly.
Unless you followed a process that was correct for setting your gains, your O-scope measurements are invalid.

Hmmm....