Too much amp for the speakers?

[3db]

It's definitely multi-factorial. The clipped power (double the rated power) could damage the speaker just as much as too much unclipped power could damage the speaker.

Let's say the limit of the woofer is 200W.

If we use a 50W amp and it clips, 100W of power would reach the woofer. Because this power is way below the limit, it doesn't matter if the signal is clipped. As long as it is below the limit, the woofer will not be damaged even if the signal is clipped.

If we use a 300W amp and the volume is crazy, 300 watts of unclipped power would reach the woofer. Because it exceeds the limit, the woofer would be damaged even if the signal was never clipped.

Now if we use a 150W amp and it clipped, 300 watts of clipped power would reach the woofer and damage the woofer too.

So the limiters can help prevent the clipping, which does help. But it does not prevent excessive unclipped power from reaching the speaker.

IOW, even if the amp has limiters, you could still damage the speakers if you use crazy volume and a powerful amp.

Bottom line, as all of us have said, don't go crazy on the amp or the volume. Most people would consider 200-300W amps as normal. If the speaker is rated for 200W, I don't think it's wrong to use a 200W amp.

If the speaker is rated for 200W max and you use a 300W amp, it is most likely okay too even if it is not "recommended" by the speaker engineer.

If the speaker is rated for 200W, I don't think it is any safer to use a 300W amp than a 200W amp.

So I think the statement "It is safer to use a more powerful amp" is less true.

I think the statement "It is safer to use an amp that is recommended by the speaker engineer" is more true.

Naturally, it is safer to use sensible safe volume period.

More accidental damage is done by under powered amps driven into clipping because users don't understand that clipping a signal is deadly on speakers. If you look at speaker damage done of a clipping amp, its always the tweeter. Clipping matters big time.

 

[AcuDefTechGuy]

More accidental damage is done by under powered amps driven into clipping because users don't understand that clipping a signal is deadly on speakers. If you look at speaker damage done of a clipping amp, its always the tweeter. Clipping matters big time.

Speaker damage secondary to the "clipping" itself or because the increased average power caused by clipping?

As PENG mentioned, the doubling of power (from 50W to 100W) due to clipping is theoretical. In the real world, the amp may shut down a little above 50W. So in this case less than 100W is sent to the speaker.

If you use 1000W and turn the volume too high, 500W of power may be sent to the speaker. 500W of power is a lot more dangerous and damaging than less than 100W, clipped or unclipped because the "clipping" part is NOT what is damaging the speaker. Excessive average power is what damages the speaker.

The clipping itself does little to the tweeter.

If you are using a 10W amp that cannot even output more than 10W and shuts down beyond 10W, no clipping in the world is going to damage the tweeter if the tweeter is truly rated for 20W of power, clipped or unclipped.

 

[AcuDefTechGuy]

- Yes a clipped output signal high frequency harmonic contents and the resulting higher average power (easily seen from the waveforms); and would theoretically be more of a threat to the tweeter or even the mid driver, but to lesser extent.
- It shouldn't make much difference to the bass drivers.
- If an amp is only rated for 50W, just because it starts clipping, it does not mean it suddenly become a 100W amp. In other words, if it is truly rated only 50W average, then above that point, it would likely be clipping and self limiting or shutting down because it won't be able to sustain an overload condition for too long without damaging itself. So again, it would either self liming due to voltage drop, or triggering the build in limiter, or triggering the protective system that shuts itself down. I think that is probably what ADTG has been alluding to, that is, more powerful amps are more of the reason for killing speakers.

Under-power (relative to the load/speaker) amps can also cause trouble to tweeters though it should represents a lesser threat especially for owners who has the minimum common sense.

Definitely agree. A 2,000W amp poses more danger to the tweeter than a 100W amp.

The mechanical and thermal limits of tweeters are significantly less than woofers. And that's the reason tweeters blow more often than woofers.

 

[PENG]

More accidental damage is done by under powered amps driven into clipping because users don't understand that clipping a signal is deadly on speakers. If you look at speaker damage done of a clipping amp, its always the tweeter. Clipping matters big time.

Since you qualified damage with "accidental", then you could be hitting the nail's head because it is reasonable to assume some users may just think there is no way a 50W amp could damage his speaker that is rated for 20 to 75W. Still, anyone who had trouble detecting sound clipped enough to damage an average tweeter has lack of what I consider minimal common sense.

I think the way the OP asked the question, he probably did not refer to "accidental" kind of damage but let's leave it to him to clarify what he really was asking.

 

[3db]

Speaker damage secondary to the "clipping" itself or because the increased average power caused by clipping?

As PENG mentioned, the doubling of power (from 50W to 100W) due to clipping is theoretical. In the real world, the amp may shut down a little above 50W. So in this case less than 100W is sent to the speaker.

Once the signal clips, it introduces a DC component that is far longer in period than the HF sine waves that are being applied to it. Its that long period that causes the voice coil to heat up and burn.

If you use 1000W and turn the volume too high, 500W of power may be sent to the speaker. 500W of power is a lot more dangerous and damaging than less than 100W, clipped or unclipped because the "clipping" part is NOT what is damaging the speaker. Excessive average power is what damages the speaker.

The clipping itself does little to the tweeter.

If you are using a 10W amp that cannot even output more than 10W and shuts down beyond 10W, no clipping in the world is going to damage the tweeter if the tweeter is truly rated for 20W of power, clipped or unclipped.

Then can you tell me why under powered amps that clip damages speakers?

 

[AcuDefTechGuy]

Once the signal clips, it introduces a DC component that is far longer in period than the HF sine waves that are being applied to it. Its that long period that causes the voice coil to heat up and burn.

http://billfitzmaurice.info/forum/viewtopic.php?t=1886

Amplifier clipping, and its respective causes and effects, is perhaps one of the most misunderstood concepts amongst audio circles. There is a whirlwind of myths surrounding this topic that seems to exceed all other topics I have come across. Now is your chance to learn the truth about clipping.

How Do Speakers Become Damaged

There are only two ways that a speaker can be damaged, both of which occur from too much input power. 1. Mechanically 2. Thermally

Every speaker has an excursion limit (often measured in mm), or how far the speaker can move forward or rearward before damage occurs. This is the mechanical limit of the speaker. This limit remains the same regardless of the use of the speaker, but the power required to reach this limit changes dependent on the enclosure. If you exceed this limit, the speaker will suffer mechanical damage, whether it's ripping your spider, bottoming out on the back plate, or any other mechanical damage. The second type, thermal damage, occurs when you exceed the thermal power handling limits of the voice coil itself. Voice coils are simple pieces of metal that will melt if too much power is applied. This limit is pretty much constant, ie. if a voice coil will be damaged at 1 kw, it will be damaged at 1kw regardless. There are two final myths to cover here. Despite the tireless efforts of some, there are still many people that believe that underpowering a speaker will damage it or that clipping will damage a speaker. Please remember that these last two thoughts are entirely UNTRUE! And now we will find out why.

Where Does This Power Come From?

Let's first understand the power potential of an amplifier when clipping. The power created is largely determined by the rail voltages. Let's compare two amps, each one connected to a 4 ohm speaker rated at 75 watts rms. Amp 1: 50 watt amp 50 Watt amp means this amp can cleanly deliver a sinewave of 50watts into a 4 ohm load. This means (Vrms)^2/4 = 50W Vrms = 14.14V Vpeak = Vrms*(1.414) Vpeak = 19.99V The rail voltages of this amp must be a bit higher, to prevent output stage distortion at this power level. In this case, the Rail voltage would have to be +/- 20 Volts. Amp 2: 75 watt amp (Vrms)^2/4 = 75W Vrms = 17.32V Vpeak = Vrms*(1.414) Vpeak = 24.49V In the example, the 75 watt amp is delivering 75 watts as it is not distorting at all. The 50 watt amp is in hard clipping, as and such, is delivering a fair bit more power. P = Vrms^2/R = (19.99V)^2/4 ohm = 100 watts. It is quite obvious that there is potential for an amplifier that is clipping to deliver substantially more power than you would expect. Keep in mind that this is only a way to determine peak voltage potential.

Average Power

Now we can get into how a speaker really gets hurt. The key issue is average power over time. Let's get to the nitty gritty. The first key is understanding Crest Factor.

"Crest Factor" is the difference between the average level of the signal and its peak level. A pure sine wave has a "crest factor" of 3dB, meaning that it's peak level is 3dB higher than its average level. We all know that 3dB represents a difference in power by a factor of 2. Another way to look at it is that the peak power of the signal is twice that of its average level. If we were to play a sine wave on our 50 watt amplifier, just below its clipping level, the average power over time the speaker would need to dissipate is 25 watts. On the other hand, a square wave has a crest factor of 0dB. In other words, its average power and peak power levels are equal. Our same 50 watt amplifier playing a square wave into our speaker requires the speaker to dissipate 50 watts. Keep in mind that this refers to sine and square waves only. Music has a much higher crest factor. Most widely available recordings have a crest factor of approximately 10dB. Looking at this in terms of power, the peak power is 10 times greater than the average power. If we were to play one of these recordings with our 50 watt amplifier when not clipping, the speaker needs to dissipate a mere 5 watts of average power over time. When the amplifier begins clipping, the peak level/power does not increase. BUT, the average power DOES increase. If we were to turn the volume up 6dB higher than the clipping level of our recording, we have reduced our crest factor to 4dB. Guess what? We are now needing the speaker to dissipate 20watts. This is four times the average power and four times the heat when measured over time. As you can see here, it is not the distortion or the waveform or anything along those lines that is killing your speaker; there is simply more average power over time. However, if the average power of time is still below what your speaker can handle, it doesn't matter if it's clipping or not. At higher power levels, the fact that a clipped signal carries more average power over time can result in damage.

DC in Clipping

One of the most famous myths regarding clipping is that it produces DC. The assumption is made because of the flat tops and bottoms to a square wave. It's incorrect to think of a squarewave as made up of positive and negative dc components. The only way for a it to be DC would be if there was a non-zero average value over long periods of time. If the polarity changes at all within the time frame that you are looking at, it is simply not DC. What are these flat portions of the signal? It is simply a combination of the fundamental frequency and all of it's higher order harmonics in sine wave form. For example, if you were to play a 20hz tone while clipping, there would be the fundamental frequency (ie. 20hz) and the second (40hz), third (80hz), and 4th (160hz) order harmonics. The sum of these frequencies creates what appears as a squarewave. There are two ways to test this for yourself; one is quite easy, the other is a little more advanced. The first way is simple if you have a variable crossover and an oscilloscope handy. Pass a low frequency square wave. You will notice the square shape on the oscilloscope. Now turn your crossover's low pass filter on. Slowly lower the setting as you approach the fundamental frequency. You will notice the waveform on your oscilloscope slowly rounding off into a typical sinewave. Once you have reached the fundamental frequency, your oscilloscope will show a perfect sinewave. The second way is for your math guys (or for those who like to use Matlab). If you look in the frequency domain using a Fast Fourier Transform, you will see the fundamental frequency and its higher order harmonics only. There will be absolutely no DC present.

Clipping and the still voice coil

The final myth is that of the still voice coil. It is perhaps the most believed myth regarding clipping. The idea is that because of the square wave, the coil is not moving during the flat portions of the signal. This is simply not true for a variety of reasons. The speaker does exhibit mechanical damping and remains in constant motion. Assuming the same voltage and excursion xmax, the cooling at any given frequency will remain the same, whether the signal is clipped or unclipped.

Summary

To provide a final review of all that we have discussed on this topic, there are only two ways to damage a speaker: Mechanically and Thermally. The only way to do this is by applying too much input power in a given enclosure (mechanically) or too much average power over time (thermally). There is no DC in a clipped signal; the coil does not stand still; air passing over the coil (and thus cooling) is the same regardless of the waveform; and clipping is acceptable provided that the average power over time is lower than the speaker's limits. The next time you hear those famed words "your speakers died because of clipping", remember what you have learned, and above all, keep searching for the truth. It's out there somewhere.

Then can you tell me why under powered amps that clip damages speakers?

Sure. It's all hearsay and anecdotes on the internet from guys who blow speakers and blame it come clipping because that is what they have been told by other guys on the internet.<O</O

 

[PENG]

Definitely agree. A 2,000W amp poses more danger to the tweeter than a 100W amp.

The mechanical and thermal limits of tweeters are significantly less than woofers. And that's the reason tweeters blow more often than woofers.

I think our comments on this topic may depend on the intent of the OP's question. Next time before we respond to an OP question on something like this we should ask 3 questions first.


View attachment 14046

 

[3db]

Amplifier clipping, and its respective causes and effects, is perhaps one of the most misunderstood concepts amongst audio circles. There is a whirlwind of myths surrounding this topic that seems to exceed all other topics I have come across. Now is your chance to learn the truth about clipping.

How Do Speakers Become Damaged

There are only two ways that a speaker can be damaged, both of which occur from too much input power. 1. Mechanically 2. Thermally

Every speaker has an excursion limit (often measured in mm), or how far the speaker can move forward or rearward before damage occurs. This is the mechanical limit of the speaker. This limit remains the same regardless of the use of the speaker, but the power required to reach this limit changes dependent on the enclosure. If you exceed this limit, the speaker will suffer mechanical damage, whether it's ripping your spider, bottoming out on the back plate, or any other mechanical damage. The second type, thermal damage, occurs when you exceed the thermal power handling limits of the voice coil itself. Voice coils are simple pieces of metal that will melt if too much power is applied. This limit is pretty much constant, ie. if a voice coil will be damaged at 1 kw, it will be damaged at 1kw regardless. There are two final myths to cover here. Despite the tireless efforts of some, there are still many people that believe that underpowering a speaker will damage it or that clipping will damage a speaker. Please remember that these last two thoughts are entirely UNTRUE! And now we will find out why.

Where Does This Power Come From?

Let's first understand the power potential of an amplifier when clipping. The power created is largely determined by the rail voltages. Let's compare two amps, each one connected to a 4 ohm speaker rated at 75 watts rms. Amp 1: 50 watt amp 50 Watt amp means this amp can cleanly deliver a sinewave of 50watts into a 4 ohm load. This means (Vrms)^2/4 = 50W Vrms = 14.14V Vpeak = Vrms*(1.414) Vpeak = 19.99V The rail voltages of this amp must be a bit higher, to prevent output stage distortion at this power level. In this case, the Rail voltage would have to be +/- 20 Volts. Amp 2: 75 watt amp (Vrms)^2/4 = 75W Vrms = 17.32V Vpeak = Vrms*(1.414) Vpeak = 24.49V In the example, the 75 watt amp is delivering 75 watts as it is not distorting at all. The 50 watt amp is in hard clipping, as and such, is delivering a fair bit more power. P = Vrms^2/R = (19.99V)^2/4 ohm = 100 watts. It is quite obvious that there is potential for an amplifier that is clipping to deliver substantially more power than you would expect. Keep in mind that this is only a way to determine peak voltage potential.

Average Power

Now we can get into how a speaker really gets hurt. The key issue is average power over time. Let's get to the nitty gritty. The first key is understanding Crest Factor.

"Crest Factor" is the difference between the average level of the signal and its peak level. A pure sine wave has a "crest factor" of 3dB, meaning that it's peak level is 3dB higher than its average level. We all know that 3dB represents a difference in power by a factor of 2. Another way to look at it is that the peak power of the signal is twice that of its average level. If we were to play a sine wave on our 50 watt amplifier, just below its clipping level, the average power over time the speaker would need to dissipate is 25 watts. On the other hand, a square wave has a crest factor of 0dB. In other words, its average power and peak power levels are equal. Our same 50 watt amplifier playing a square wave into our speaker requires the speaker to dissipate 50 watts. Keep in mind that this refers to sine and square waves only. Music has a much higher crest factor. Most widely available recordings have a crest factor of approximately 10dB. Looking at this in terms of power, the peak power is 10 times greater than the average power. If we were to play one of these recordings with our 50 watt amplifier when not clipping, the speaker needs to dissipate a mere 5 watts of average power over time. When the amplifier begins clipping, the peak level/power does not increase. BUT, the average power DOES increase. If we were to turn the volume up 6dB higher than the clipping level of our recording, we have reduced our crest factor to 4dB. Guess what? We are now needing the speaker to dissipate 20watts. This is four times the average power and four times the heat when measured over time. As you can see here, it is not the distortion or the waveform or anything along those lines that is killing your speaker; there is simply more average power over time. However, if the average power of time is still below what your speaker can handle, it doesn't matter if it's clipping or not. At higher power levels, the fact that a clipped signal carries more average power over time can result in damage.

DC in Clipping

One of the most famous myths regarding clipping is that it produces DC. The assumption is made because of the flat tops and bottoms to a square wave. It's incorrect to think of a squarewave as made up of positive and negative dc components. The only way for a it to be DC would be if there was a non-zero average value over long periods of time. If the polarity changes at all within the time frame that you are looking at, it is simply not DC. What are these flat portions of the signal? It is simply a combination of the fundamental frequency and all of it's higher order harmonics in sine wave form. For example, if you were to play a 20hz tone while clipping, there would be the fundamental frequency (ie. 20hz) and the second (40hz), third (80hz), and 4th (160hz) order harmonics. The sum of these frequencies creates what appears as a squarewave. There are two ways to test this for yourself; one is quite easy, the other is a little more advanced. The first way is simple if you have a variable crossover and an oscilloscope handy. Pass a low frequency square wave. You will notice the square shape on the oscilloscope. Now turn your crossover's low pass filter on. Slowly lower the setting as you approach the fundamental frequency. You will notice the waveform on your oscilloscope slowly rounding off into a typical sinewave. Once you have reached the fundamental frequency, your oscilloscope will show a perfect sinewave. The second way is for your math guys (or for those who like to use Matlab). If you look in the frequency domain using a Fast Fourier Transform, you will see the fundamental frequency and its higher order harmonics only. There will be absolutely no DC present.

Clipping and the still voice coil

The final myth is that of the still voice coil. It is perhaps the most believed myth regarding clipping. The idea is that because of the square wave, the coil is not moving during the flat portions of the signal. This is simply not true for a variety of reasons. The speaker does exhibit mechanical damping and remains in constant motion. Assuming the same voltage and excursion xmax, the cooling at any given frequency will remain the same, whether the signal is clipped or unclipped.

Summary

To provide a final review of all that we have discussed on this topic, there are only two ways to damage a speaker: Mechanically and Thermally. The only way to do this is by applying too much input power in a given enclosure (mechanically) or too much average power over time (thermally). There is no DC in a clipped signal; the coil does not stand still; air passing over the coil (and thus cooling) is the same regardless of the waveform; and clipping is acceptable provided that the average power over time is lower than the speaker's limits. The next time you hear those famed words "your speakers died because of clipping", remember what you have learned, and above all, keep searching for the truth. It's out there somewhere.<o>

I said it introduces a DC component .. NOT DC!! the squared off top of the signal is much longer in duration than the high frequencies the tweeter it normal receives and its the squared signal component that damages the tweeter. That is due to clipping. An under powered amp can easily destroy a tweeter when the signal is clipped. And if you are so sure that underpowered amps don't clip, I suggest buying a used AVR, hooking your speakers up to it,crank the volume to its max with a CD playing and see how long the tweeters last or feed your tweeters square waves and see how long they last.

Why Do Tweeters Blow When Amplifiers Distort?


When an amplifier is overdriven, the sound becomes distorted. This manifests itself in many ways, but the two we are interested in are the generation of harmonics, and the reduction of dynamic range - both the true dynamic range and the peak to average ratio. Let's assume that the amp is overdriven by a mere 3dB, so the average level is now 20W, and the peaks are clipping. With many systems (or listeners), this will be virtually inaudible. Careful listening will uncover the fact that there is distortion present, and there is a definite reduction of intelligibility.

The speakers - both tweeters and woofers, are now being asked to absorb twice the power that would be normally obtainable, and the power is more constant - the signal is compressed by the power amp. Add to this the additional harmonics generated by the clipping waveform, and the tweeter may actually be getting up to 3 times the continuous power that was available before clipping. Peak power remains the same, since it is limited by the amplifier's power supply voltage.
Now, let's overdrive the amp by 10dB. The amp is delivering in excess of 100W, since it is reproducing square waves much of the time. The woofer will be subjected to perhaps a continuous 100W of power, and around 15W continuous will be available to the poor tweeter. Of this, probably less than 1% will be converted into sound (1% represents an efficiency of about 92dB/W/m). Ferrofluid helps, but virtually no hi-fi tweeter can withstand that sort of continuous power for any duration.
The tweeter was never designed for that! Just look at a 10W wirewound resistor for example. It is big and chunky, and made from a ceramic material that is designed to handle a lot of heat. Run one at 10W to find out just how much heat you will get. There is very little airflow around the tweeter voice coil, and the heat has nowhere to go. The result is that the voice coil will quickly overheat, and the adhesive that bonds the coil to its former, the former itself, and even the enamel insulation on the coil will be damaged. The result (naturally) is a dead tweeter.
As for the woofer - unless it is designed to take 100W or more continuous sinewave power, it will also overheat and eventually die. It takes a lot longer, because there is airflow around the voice coil, and the coil is bigger and has greater thermal inertia, but die it must if the abuse is maintained. </o

 

[AcuDefTechGuy]

I think our comments on this topic may depend on the intent of the OP's question. Next time before we respond to an OP question on something like this we should ask 3 questions first.


View attachment 14046

Best damn show. Season 05 premieres Oct 12.

 

[PENG]

Once the signal clips, it introduces a DC component that is far longer in period than the HF sine waves that are being applied to it. Its that long period that causes the voice coil to heat up and burn.

As long as the amp clips symmetically as it should, it will still be AC just with lots of harmonics. Theoretically there will always be some DC offset clipping or not but the magnitude should be so low that even cheap amps can pass for having negligible effects. Also don't forget that crossover blocks low frequencies to the tweeter let alone DC.

 

[3db]

As long as the amp clips symmetically as it should, it will still be AC just with lots of harmonics. Theoretically there will always be some DC offset clipping or not but the magnitude should be so low that even cheap amps can pass for having negligible effects. Also don't forget that crossover blocks low frequencies to the tweeter let alone DC.

I don't mean DC in the strict definition... I'm saying that the flat part of the clipped signal is delivering more power longer to the tweeter than what a sinusoidal wave would deliver.. making it appear as DC time wise compared to that of an unclipped signal. That is why clipping is so inherently deadly to tweeters.

I'm not even going to debate overly powerful amps ..... we both know that they can kill both woofers and tweeters... that's just common sense.

 

[PENG]

Best damn show. Season 05 premieres Oct 12.

North of the border we are only just getting season 4, but we also pay less.

So who is going to create the 3 questions on threads about under/over power amp? I suggest 3 dB to come up with the first one first, common guys, those are the funniest kind of threads/posts that typically goes in circle..

 

[AcuDefTechGuy]

I said it introduces a DC component .. NOT DC!! the squared off top of the signal is much longer in duration than the high frequencies the tweeter it normal receives and its the squared signal component that damages the tweeter.

From the same article you linked:

...The common misconception is that the distortion creates harmonics, and the additional harmonic content destroys the tweeter. Not really - woofers and midrange drivers can also blow from a distorted amp, and this is unlikely to have anything to do with harmonics...

My take: it is not the "squared signal component" that damages the speaker. It is the excessive average power that damages the speakers.

Perhaps we are just miscommunicating. Perhaps that is exactly what you are saying - that the clipping can produce the excessive power. And the excessive power is what damages the speakers.

Let me ask you this. From an engineering perspective. If the speaker engineer recommends to use 100W-200W amp for the speaker, is it a bad idea to use a 100W-200W amp? Is the engineer wrong for making such a recommendation?

 

[3db]

North of the border we are only just getting season 4, but we also pay less.

So who is going to create the 3 questions on threads about under/over power amp? I suggest 3 dB to come up with the first one first, common guys, those are the funniest kind of threads/posts that typically goes in circle..

Rules
1.) If your amp/avr are rated for higher power than your speakers, never turn the amp/avr past half way.
2.) If your amp/avr has equal power rating to the speakers, never turn the amp/avr past half way.
3.) If your amp/avr is much more powerful than your speakers:
don't operate when drunk or allow drunk friends to operate
listen carefully to your speakers so they don't strained or making any other funny noises

 

[3db]

From the same article you linked:

...The common misconception is that the distortion creates harmonics, and the additional harmonic content destroys the tweeter. Not really - woofers and midrange drivers can also blow from a distorted amp, and this is unlikely to have anything to do with harmonics...

My take: it is not the "squared signal component" that damages the speaker. It is the excessive average power that damages the speakers.

Perhaps we are just miscommunicating. Perhaps that is exactly what you are saying - that the clipping can produce the excessive power. And the excessive power is what damages the speakers.

We are saying the same thing. Its the flat part of the waveform where the excessive power occurs but its excessive because of time at the amplitude, not amplitude itself..... I disagreed with your point that clipping is only secondary.... Clipping causes the condition to occur.

 

[PENG]

I don't mean DC in the strict definition... I'm saying that the flat part of the clipped signal is delivering more power longer to the tweeter than what a sinusoidal wave would deliver.. making it appear as DC time wise compared to that of an unclipped signal. That is why clipping is so inherently deadly to tweeters.

No argument here, but ADTG is only emphasing the truth about the average power is what does the damage. To recap, I think all 3 of us can agree on:

First, let's define underpower as when the ratio of rated amp power to rated speaker power handling capability <0.5 and overpower as the same ratio being >2.

1) Square or near square wave signal contains more aveage power than sine waves or near sine wave with the same peak voltage.

2) Given the same peak (crest) voltage, square waves will therefore produce more heat in the speaker.

3) Near square wave contains more average power because it has much more harmonics and is therefore more of a threat to tweeters that will readily accept high frequencies by design.

4) Overpower amp can damage speakers (as you said, this is common sense)

5) Underpower amp can also damage speakers (also common sense but only for those who has a little deeper understanding of the physics behind).

And we may or may not agree on the following because that's when the definition of common sense could become undefinable and are difficult to prove one way or the other.

1) An underpower amp, e.g. a 50W amp driving a 100W rated speaker will less likely damage a speaker than an overpower amp will. Example: a 50W amp cannot produce 100W of power while clipping heavily for too long before it's protective system should kick in or the owner should intervene soon enough, or the amp itself will fail.

2) Underpower amps might have damaged more tweeters than overpower amps do because they might have given the owners alse sense of security, when in fact they could potentially send more average power than a tweeter can handle even if the speaker as whole has a higher power handling capability than the amp is rated for.

One can see easily why this topic tends to go in circle.

 

[AcuDefTechGuy]

North of the border we are only just getting season 4, but we also pay less.

So who is going to create the 3 questions on threads about under/over power amp? I suggest 3 dB to come up with the first one first, common guys, those are the funniest kind of threads/posts that typically goes in circle..

Netflix is slow as heck on all sides of the borders.

I don't use Netflix anymore. Only my wife and kids use Netflix.

Question #1: How many amps have you killed?
Question #2: How many speakers (drivers) have you killed?
Question #3: Why did you turn up the volume?

 

[3db]

1) An underpower amp, e.g. a 50W amp driving a 100W rated speaker will less likely damage a speaker than an overpower amp will. Example: a 50W amp cannot produce 100W of power while clipping heavily for too long before it's protective system should kick in or the owner should intervene soon enough, or the amp itself will fail.

I personally would not want to rely on the protection circuit.

2) Underpower amps might have damaged more tweeters than overpower amps do because they might have given the owners alse sense of security, when in fact they could potentially send more average power than a tweeter can handle even if the speaker as whole has a higher power handling capability than the amp is rated for.

One can see easily why this topic tends to go in circle.

Exactly.

 

[PENG]

From the same article you linked:

...The common misconception is that the distortion creates harmonics, and the additional harmonic content destroys the tweeter. Not really - woofers and midrange drivers can also blow from a distorted amp, and this is unlikely to have anything to do with harmonics...

My take: it is not the "squared signal component" that damages the speaker. It is the excessive average power that damages the speakers.

Perhaps we are just miscommunicating. Perhaps that is exactly what you are saying - that the clipping can produce the excessive power. And the excessive power is what damages the speakers.

Let me ask you this. From an engineering perspective. If the speaker engineer recommends to use 100W-200W amp for the speaker, is it a bad idea to use a 100W-200W amp? Is the engineer wrong for making such a recommendation?

That's why I agree with you that we should emphasize the term "average" power. I also believe in theory overpower amp would cause more speaker damages than underpower amps do because underpower amps must clipp first, in order produce the excessive harmonics that would result in sending higher average power to speakers, and only if time is in their favor (i.e. sustained long enough) for them to damage the speakers. Even then, they tend to be of much lower risk to the woofers.

Having said that, I have no proof, and I doubt there are any statistics out there. So it boils down to just whatever one choose to believe. I believe what I believe only base on my perceived logic of events.

 

[AcuDefTechGuy]

We are saying the same thing. Its the flat part of the waveform where the excessive power occurs but its excessive because of time at the amplitude, not amplitude itself..... I disagreed with your point that clipping is only secondary.... Clipping causes the condition to occur.

Yes, I agree that clipping can be a significant factor because it can cause excessive power.

But I also think that excessive power will occur regardless of clipping if a person were to crank the volume all the way up.

For example - using a 100W amp that clips at extreme volume (but otherwise would never clip) or using a 300W amp that does not clip at extreme volume. Both cases can damage the speakers.

I guess it's a double edge sword. Both sides can cut you just as easily.

It's probably the same exact thing all of us are saying, just different ways and in circles.