Maybe I should repeat this

Doesn't matter anymore. I was trying to illustrate another possibility, but since I cannot say 100% sure if I was clipping, even though I had set all my gains properly and had not clipped previously, I suppose I cannot rule this out after all. Which furthers my stance that one should always buy a more powerful amp because, even though your gains may be set properly, you just can never say for sure if you were clipping. Therefore, it is better to err on the big side.

Nevertheless, Richard Clark has stated, "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". **I have listed several respected people that take issue with that.**

In the very beginning, I had stated, "remember, your amp should always be able to put out more than your drivers are rated at, never the other way around."

Then Tempe said, "And why do you recommend AGAINST an amp that is rated for less than what the sub is rated for?"

I said, "Well, its not a hard n fast rule, but basically, an amp should be able to put out more watts than the sub can take."

This is what started it all, the issue of whether or not to recommend an amp have more power than the driver is rated. I maintain it is. Maybe I'm not the guy who can prove it (with or without clipping), but I don't care. I am very satisfied with my beliefs on the subject.

If you want proof, contact Thomas P. Colvin who said, "There is a fallacy that a heavy cone will produce better bass. WRONG! There is also the fallacy that a stiff cone suspension means higher power handling. WRONG AGAIN! The truth is that if the cone is heavy, it will not react quickly to the input signal. Hence without the application of considerable wattage, the signal will be gone from the line before the cone can move and thereby causing an undesirable noise, kind of a flopping honk sound. Not to mention the other restrictions placed on a speaker with a heavy cone. The same thing can happen with a suspension that is too stiff." (Thomas P. Colvin -- Musicians Hotline)
http://www.musicianshotline.com/archive/tech/reconing.htm

Until you disprove this, I only need to keep requoting it at the question of, "how can a sub be blown with clean power?"

geolemon said, "a bit of clipping is actually quite common and relatively harmless."

geolemon said, "Small amounts of clipping won't even hurt too much"

geolemon said, "In fact, even if you do have it set to clip a bit, that won't hurt anything."

MFCT said, "Nope. Clipping will not harm speakers. Its a myth. Pushed into the mainstream back in the early 70's by JBL and followed blindly decades to come."

geolemon said, "GIVEN the amp is not clipping (user error).." **Not necessarily user error, it is surely possible to set gains properly and still not be 100% sure you are not clipping. But, had you bought a more powerful amp, you could be more sure.**

Richard Clark said, "clipping is not the key to anything"

David Navone said, "Not only do we recommend "clipping" the amp, we recommend that it be super clipped"

David Navone said, "Clipping doesn't damage speakers"

geolemon said, "Clipping does not destroy speakers.... and clipping extremely underpowered speakers does abosolutely nothing."

RanDawg said, "Didn't someone here say no amount of clipping will damage a sub? I know of several posts that say minimal clipping is fine. Therefore, clipping has nothing to do with anything in this case. It is merely to prove or disprove that an amp of lower rated power than a sub has the ability to blow it."

RanDawg said, "I then play around with various gain settings at various frequencies and recording levels until I am satisfied I will not clip under most circumstances and yet still have headroom for poorly recorded music."


Needless to say, I'm very satisfied with my recommendations to others about amp selection.

 

[updated:LAST EDITED ON 01-12-03 AT 11:45 PM (EST)]>It has to do with the amount of headroom above the 'watt' in question

Headroom has NOTHING to do with how much energy is in any particular watt. A watt ALWAYS has the same ammount of power! Your saying that a watt has less energy as you have more of them. Think of this in length again. Going by what your saying, as you measure a longer distance, your units get smaller, so an inch 1 foot away is shorter than an inch 10 feet away. Anyone can see this is not the case.

>>
>>Now for the topic of underpowering blows the speaker.
>>
>>Low damping factor can not, and will not blow a sub. It
>>will make distort more, but it will not overheat or cause
>>the sub to go beyond its limits of excusion simply because
>>the DF is low. Since your an EE, I have a project for you,
>>it will cost less than $40, and probably wont take more than
>>an hour of work. Build a small and simple amp that can only
>>put out about 100 watts or so, and record a CD with a pure
>>square wave for 1 track qand set it to repeat, and run the
>>output of that CD to the input of your amp, turn the amp up
>>FULL BLAST, as loud as it can go. Hell, clip the input
>>stage too for good measure. Now hook that nice and clipped
>>output to a speaker rated for about 500watts RMS or more in
>>a .75cu ft sealed enclosure, and let it play. See how long
>>it takes to blow the speaker. (hint: dont hold your breath)

>The heavier the cone, the harder it is to control. The greater the
>power handling capabilities of the driver, the likelihood is, it
>will TAKE more power to properly drive it

That doesnt even have anything to do with what I said. Re-read what I posted and give me an on-topic reply please.

>Tell you what, scape up a couple cheap subs of equal quality. Put
>them in equal boxes. Hook one up to an amp that is overpower, and
>one that is underpower. Play a sinewave, your choice. Measure the
>spl so they are equal. Then gradually turn up the gains while
>keeping the spl equal between the two. Let me know which one blew
>first. Although this proves nothing, it is interesting no less.

As you turn the gains up on the small amp, you will push it far into clipping trying to keep up with the larger amp. This is clipping causing a speaker to overheat, not underpowering. try again.

>There are a lot of "technically uninformed or totally ignorant" people in the world.

Oh the Irony.

You cite many examples of, *gasp*, CLIPPING in reply 209 on 01-12-03, 08:28 PM (EST). None of that has ANYTHING to do with an amplifier being stressed or underpowering. Now, im sure you understand that RMS (root mean square) power is the average power of a sine wave correct? And to get the RMS power of any sine wave you multiply 0.707 by its peak power. The reason for this is because a sine wave is not always at its peak amplitude, so the average power will not equal its peak power. A square wave is ALWAYS at it's peak amplitude. This means that a square wave's average power is the same as its peak power. now, suppose we have a speaker that is rated for 500w RMS, and an amplifier than can put out a mere 350 watts RMS and 650 watts peak. Now, say we crank the volume, and drive the amplifier into hard clipping. This means the amplifier is now outputting a 650 watt RMS SQUARE wave to our sub than can only handle 500watts RMS. Not only is this more power than it can handle, but also the sub is now pausing at the the top and bottom of the wave, causing lower air circulation, causing even MORE heat to build up. the result? a burnt voice coil. This is why lower power amps can burn up higher power speakers. It has NOTHING to do with underpowering, in fact, clipping causes OVERPOWERING. Do you understand now?

*edit*
I read my post and thought of something I wanted to add:

Suppose we have our same 500watt RMS subwoofer, and a 50watt RMS, 100watt peak amp. Now say we run this amp into HARD clipping and output a 80watt RMS square wave, our 500watt RMS subwoofer will laugh at this power, and will play the square wave as long as you want it to (which goes back to my post about you building an amp)

 

Well, geolemon, can you make up your mind? Is clipping good, or bad?
You seem to have a double standard.

How about you Richard Clark, is clipping good, or bad?

About the only one that has been consistent is David Navone, who said, "Not only do we recommend "clipping" the amp, we recommend that it be super clipped"

I have listed several respected people to take issue with this, including math professors, engineers, musicians and speaker repairmen.

 

so what i have seem to understand is when a smaller amp is connected to a high power subwoofer the operator turns the bass option to max, to make the sub meet its potentials. this causes the amp to clip blowing the subs....so pretty much i understand it as pushing the amp too hard.

 

>
> I suppose I cannot rule this out
>after all.
>

Why not? You were adamant.. and you said yourself, you scoped the outputs just a day prior... did you touch your gains in the next day?
If so, it doesn't take a technical professional, scientist, EE, or scholar (some of which you claim to be.. I lost track) to realize that would invalidate the scoping results... of course you wouldn't have mentioned it then...
I would say that IF you scoped your outputs a day prior, using proper gain-setting techniques (yes...), that this definitely would have ruled out clipping as a factor. In fact, setting with a scope this way would have led to actually ultra-conservative gain settings.. those that wouldn't display a hint of clipping even at 0dB levels (which doesn't reflect reality.. which is why I said a little clipping is acceptible...)!

>
>Which furthers my stance that one should always
>buy a more powerful amp because, even though your gains may
>be set properly, you just can never say for sure if you were
>clipping. Therefore, it is better to err on the big side.
>
No, actually you just proved that if you have a bigger amp, you are closer to thermalling the sub anyways, inherently.
Therefore, it would take smaller amounts of clipping to send the subwoofer over that "threshhold".
The smaller amp is the safer amp, always.
The only ONLY downside to the smaller amp is less potential output.
Everything else is a positive.


>
>If you want proof, contact Thomas P. Colvin who said, "There
>is a fallacy that a heavy cone will produce better bass.
>WRONG!
>
His point here is because moving mass directly affects Fs and VAS, two factors that directly correlate to a subwoofer's low bass potential.
It doesn't tie to powerhandling... it ties to methods of acheiving a low Fs without using inherently heavy cone, former, windings, or mass-adding techiques. Loudspeaker driver design issues.
Trust me, I am familiar with them...

>
>There is also the fallacy that a stiff cone
>suspension means higher power handling. WRONG AGAIN!
>
His point here ties to the relationship between the resistance against cone excursion and the possibilities of bottoming the subwoofer out... the mechanical powerhandling of the subwoofer if you will, which is completely independent of electrical powerhandling (which is half of his point, I am sure)...
Inherent in the driver itself, if you have a very low VAS (suspension compliance), it takes more power to reach maximum excursion levels than if you have a higher VAS.
The other half of his point, I am sure, was to suggest that you can have the same level of "mechanical powerhandling" in a subwoofer with a higher VAS.. because it matters not what the subwoofer does by itself, in free-air representation... what matters is what the subwoofer/enclosure combination perform like, together... and the enclosure itself augments the suspension of the subwoofer (dynamically however... you need to be aware of how it augments the subwoofer by frequency now!)
His point is valid...
But it doesn't relate to thermal powerhandling...
And I went to great lengths to allow you to make statements that would have allowed you to slip through this loophole, ie. "I played a 20Hz tone in my large box tuned to 50Hz..."


>
>The
>truth is that if the cone is heavy, it will not react
>quickly to the input signal. Hence without the application
>of considerable wattage, the signal will be gone from the
>line before the cone can move and thereby causing an
>undesirable noise, kind of a flopping honk sound.
>
So his point here is that you might design a loudspeaker driver so poorly that it takes significant amounts of power to get it moving, and even then, it results in a sloppy sounding driver.
This isn't anything the world didn't know, and it's one reason why people don't design subwoofers this way...
Particularly JL Audio, who has been KNOWN for revolutionizing the industry with small box subs that DIDN'T accomplish small VAS numbers by using high mass... to the contrary, they used lightweight, accurate cones, yielding both high quality sound, in small enclosures.
This was a 12W6 you had, right?
Bear in mind, the W6 series has earned JL more industry awards in design, engineering, and performance than any other subwoofer they have ever made... (although the W7 is IMO more deserving... and given the same amount of time, I am sure will prove true)

>
>Not to
>mention the other restrictions placed on a speaker with a
>heavy cone. The same thing can happen with a suspension that
>is too stiff." (Thomas P. Colvin -- Musicians Hotline)
>http://www.musicianshotline.com/archive/tech/reconing.htm
>
The suspension is an inherent restriction on cone movement... this has nothing to do with powerhandling, and the degree will vary from subwoofer to subwoofer.
Moving mass ("heavy cone".. but also voice coil windings, former, etc) is directly tied to VAS as well.
But these are loudspeaker design parameters.

Regardless of all this, any subwoofer...
Even one that is poorly designed..
Will fail less often on LESS power than it will on MORE power.

Is your argument that heavy cone / stiff suspension = less cone movement = more heat = premature failure?
If you have less power, you have less heat.. regardless of cone movement. Period.




>Until you disprove this, I only need to keep requoting it at
>the question of, "how can a sub be blown with clean power?"
>
Well, there you go (look up). Not disproven, HE is correct.
YOU don't understand what he is discussing...
Talk about "out of context"...

>
>geolemon said, "a bit of clipping is actually quite common
>and relatively harmless."
>
>geolemon said, "Small amounts of clipping won't even hurt
>too much"
>
>geolemon said, "In fact, even if you do have it set to clip
>a bit, that won't hurt anything."
>
>MFCT said, "Nope. Clipping will not harm speakers. Its a
>myth. Pushed into the mainstream back in the early 70's by
>JBL and followed blindly decades to come."
>
>geolemon said, "GIVEN the amp is not clipping (user
>error).." **Not necessarily user error, it is surely
>possible to set gains properly and still not be 100% sure
>you are not clipping. But, had you bought a more powerful
>amp, you could be more sure.**
>
>Richard Clark said, "clipping is not the key to anything"
>
>David Navone said, "Not only do we recommend "clipping" the
>amp, we recommend that it be super clipped"
>
>David Navone said, "Clipping doesn't damage speakers"
>
>geolemon said, "Clipping does not destroy speakers.... and
>clipping extremely underpowered speakers does abosolutely
>nothing."
>

Clipping does not destroy speakers, heat does... and you get heat from power. More power, more heat. With a load that is at least partly resistive, more voltage = more heat.
In the case of a subwoofer, between 98.5% and 99.5% of the power put into a subwoofer is burned up as heat.
More power, more heat.

Consider this:
- Let's assume for a second that a subwoofer is 4 ohms exactly across it's entire frequency spectrum (just for example's sake).
- Let's assume that this subwoofer can take 300 watts just fine, but over that will exceed it's thermal limits.
- Let's also assume that the enclosure isn't a factor here.

If you take a 200 watt amp, and set it so that it never clips, you will never cause the subwoofer to fail.
However, if you are clipping nearly into a square wave, you can see how your RMS would go up, correct?
It would go up to nearly 400 watts, for all intents and purposes.

YOUR RECOMMENDATION:
It is safer to run larger, rather than smaller.
Now, if you take a 300 watt amp, and set it so it never clips, you are RIGHT on the borderline, relative to our example here. If you do end up setting your gain so that it clips even just 10%, you will go over the border and cause a woofer failure.. at least some percent of the time.

MY POINT:
It is safer to run smaller rather than larger.
If you take a 100 watt amp, and set it so it never clips, you will never cause the woofer to fail.
If you take the 100 watt amp, and set it so that it is clipping the signal into nearly a square wave, again, you double the RMS voltage put out by the amp. Even still, this only results in about 200 watts, RMS. Again, you will never cause the woofer to fail on this amount of power.


THIS is a PROOF that less power is safer.
(surely you must be familiar with "proofs", being a student... er, scholar)
You have not established any evidence, or set up any proofs that indicate that MORE power is SAFER.
Although that has been your claim throughout this whole thread.

Less power is safer, as proven.

 

>Well, geolemon, can you make up your mind? Is clipping
>good, or bad?
>You seem to have a double standard.
>
>How about you Richard Clark, is clipping good, or bad?
>

I am shocked that someone of your "experience" and "education" does not understand the correlation between clipping and power..
And power and heat.
And heat and thermal failure.

I maintain, as I have always, how much clipping is tolerable is relative to how much power you are feeding into the subwoofer...
(all things being "relative"... another scholarly concept)

As mentioned above:
If you are feeding (as you recommend) the full RMS power rating worth of power to the sub... then you can only tolerate RELATIVELY small amounts of clipping before you send the subwoofer beyond it's RMS threshold, correct?
If you are feeding a smaller portion of the full RMS power rating worth of power to the sub... then you can tolerate more clipping than you could if you were sending full power to the sub, without risk of failure.
The less power to the sub, the more clipping the subwoofer can withstand without damage.

Does that clarify it for you?
(silly of me to assume you could make that basic correlation)



And as regards your snide comment...
Clipping is never "good"... no one has said that.
But it's perfectly ACCEPTIBLE if you are at a LOW ENOUGH POWER LEVEL that it doesn't harm the woofer, and clipping itself is at a low enough level as to be inaudible.
(to make that point yet AGAIN...)

 

[updated:LAST EDITED ON 01-13-03 AT 00:44 AM (EST)]RanDawg -
David said that clipping is ok, and that he even severly clips sometimes, and thats ok, as long as the power and heat that the clipped signal produces doesnt exceed the MECHANICAL OR THERMAL LIMITS.

Ask David, I'm sure he will be willing to back me up on this as will others.

 

>so what i have seem to understand is when a smaller amp is
>connected to a high power subwoofer the operator turns the
>bass option to max, to make the sub meet its potentials.
>this causes the amp to clip blowing the subs....so pretty
>much i understand it as pushing the amp too hard.


You are close...

The USER is pushing the amp too hard, by setting the amp up so that it clips (or takes an amp that was set to maximum-gain-before-clipping, and cranked the bass **** up, effectively causing the same thing)...
Amps aren't supposed to be set to clip.. It's the user who sets the amp up who determines the gain setting.
It's there so that you can match the output voltage of your head unit to the input voltage of your amp, that's all.
So part of your answer comes in the form of "If your amp is clipping, it's user error.. shouldn't be doing that.."

The other part that you need to understand is that RMS voltage (power) doubles if you clip the wave so radically it becomes a square wave. In reality, it never is really THAT extreme, but power increases somewhere greater than what the amp was built to provide.

The larger the amp, the more resulting power this will put through the subwoofer...
And the more power you put through the subwoofer (if you exceed the RMS rating of the sub) the sooner it will die.

The only reason theoretically that you could blow a 200 watt sub with a 300 watt amp was if you were clipping it so extremely that the 200 watt amp really sent more like 300+ through the sub.
Definitely user error at that point, because it would have been very audible by that point.. bad sound quality.

But regardless.. a smaller amp is safer.
A larger amp may be the recommended route to go... But that's going to be based on nothing but SPL potential, and sound quality benefits from increased overhead, etc...
Has nothing to do with woofer longetivity... it's inversely proportional, inherently...
Despite what RanDawg wants to believe.

 

In a car wreck, an amp could be thrown through the cabin and kill the driver. (read: underpowered amp sending clipped signals to a slighly above RMS speaer) Does this mean we shouldn't put amps in our car? (read: dont underpower subs)


Just cause it could happen because of other parts of a "system" not being right or failing (read: car wrecking/amp sending excessive heat and power, thus exceeding thermal or mechanical limits), doesn't mean its an absolute no-no to do. (read: it's ok to underpower, if set up sensibly)

 

thats what i meant, i just didnt ellaborate, i posted the bottom line.


the user pushes the amp to clip which doubles the power to the speakers which blows it. sooo a smaller amp can hurt a larger speaker. the amp causes distortion and damages the speaker. so for the average customer the larger amp would be ideal so that he/she does not try to push the amp to extreme measures. i do understand it now but do not want to type it all over again.

 

>thats what i meant, i just didnt ellaborate, i posted the
>bottom line.
>
>
>the user pushes the amp to clip which doubles the power to
>the speakers which blows it. sooo a smaller amp can hurt a
>larger speaker. the amp causes distortion and damages the
>speaker. so for the average customer the larger amp would be
>ideal so that he/she does not try to push the amp to extreme
>measures. i do understand it now but do not want to type it
>all over again.

But remember, a user that's not sasified with a 200W amp on a 300W sub will most likely clip the signal to sound louder. Now, lets say, you have a 400W amp now. You set it so the gains are perfect. Now you go and sit in your car to check it out. To your surprise, it sounds just as loud as the 200 watt amp (read: distortion makes it sound louder). What the hell? So now this same user goes and clips this 400W amp so it gets louder, distorting it at the same time. So what I'm trying to say is that you need to be smart about your equipment. If it doesn't sound loud enough to you, don't go clipping the hell out of your signal. Invest into better speakers, or a better box, etc. You have to be smart about your install. Best thing I can say for the "Average User" is have someone that knows what they are doing set up your equipment until you grasp on how stuff works and what will make it not work.
Sorry if my post is confusing/stupid.
Quinton.

 

I was not all that adamant, I was pretty sure. One thing is sure, it did blow.

RanDawg said post#32, "I am all but positive my JL wasn't seeing a clipped signal when it died."

RanDawg said post#54, "Like I said over n over, it wasn't clipping. Go read." **Guess I could not have said so for sure, even if I was positive I had no clipping the day before, I would have set the gains with setup cds and not metallica, which is what was playing when the sub seized, my appologies and thanks for bringing me to this realization.**

RanDawg said post#55, "I am aware of clipped signals and Inever let my equipment clip, go read my posts." **This is true except I actually have no real control over clipping unless I buy a LARGE amp. Large amps are your only real prevention for clipping.**

RanDawg said post#61, "Furthermore, often one medium is not recorded at the same level as another; therefore, you must account for the recording level when you are setting gains. You cannot trust broadcast signals either. They can vary as well."

RanDawg said post#62, "I don't believe in bass boost, my gain rarely exceeds 25%-40%. I have stated this weeks ago in another thread here. I worry if I find I have to set a gain near 50% and look for a problem somewhere."

RanDawg said post#171, "Didn't someone here say no amount of clipping will damage a sub? I know of several posts that say minimal clipping is fine. Therefore, clipping has nothing to do with anything in this case. It is merely to prove or disprove that an amp of lower rated power than a sub has the ability to blow it."

RanDawg said post#178, "I then play around with various gain settings at various frequencies and recording levels until I am satisfied I will not clip under most circumstances and yet still have headroom for poorly recorded music."

RanDawg said post#205, "I said it was very unlikely the amp was clipping. The gains were set with an oscilloscope some time before the day in question."


But geolemon, did you make up your mind if clipping is good or bad?

geolemon said post#51, "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"

geolemon said post#59, "Large amounts of clippnig, that's another story."

geolemon said post#77, "A grossly clipped sudden peak that worked out to twice the RMS wattage of your sub (which, would be dramatic, if we are talking about an amp that is supposed to be UNDERpowering your subs, right?)"

geolemon said post#77, "The "too little power" didn't kill the sub, the "clipping quantity" killed the sub."

geolemon said post#77, "The thing that caused the failure was the adjustments made to the amp, resulting in clipping."

geolemon said post#153, "Clipping does not destroy speakers.... and clipping extremely underpowered speakers does abosolutely nothing."

Not only did you put yourself at odds with Richard Clark and David Navone in the beginning, but then at post#153, you turned on yourself. Now if I am to understand, you are back at clipping being ok again. I really wish you would get your story straight.

 

Read my reply again. Clipping is ok when the added power and heat doesnt exceed the mechanical or thermal limits of the sub.
RC, DN would both agree with me. A 200w amp clipping would not exceed the power or heat of a grossly higher rated sub.
a 200w amp clipping could blow a similarly matched sub.

 

>RanDawg -
>David said that clipping is ok, and that he even severly
>clips sometimes, and thats ok, as long as the power and heat
>that the clipped signal produces doesnt exceed the
>MECHANICAL OR THERMAL LIMITS.
>
>Ask David, I'm sure he will be willing to back me up on this
>as will others.

Oh no no, you can't do that now. No double standards

David Navone said post#153, "Not only do we recommend "clipping" the amp, we recommend that it be super clipped"

David Navone said post#153, "Clipping doesn't damage speakers"

David Navone. Carsound Magazine

 

>Not only did you put yourself at odds with Richard Clark and David
>Navone in the beginning, but then at post#153, you turned on
>yourself. Now if I am to understand, you are back at clipping being
>ok again. I really wish you would get your story straight.

If you truely believe what you just said, there is no hope for you. Every quote you just used was out of context, which im pretty sure you dont understand so I will explain it to you. When you remove most of the information from a statement, and only quote the part that servers your interest, its called quoting out of context, its very unethnical, and completely invalidates what your are trying to prove by using the quote.