Clipping Damages Speakers - Yes or No
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restorer-john
Addicted Member
You are very confused.
I am happy to demonstrate for you anytime how I can obliterate a tweeter in a 200watt speaker system with a 20w amplifier, clipping or not.
It is the shift in spectral energy distribution, by whatever method, be that clipping compression or oscillation that destroys tweeters and mids. Woofers don't suffer from that.
A speaker system rated at 200watts will often have a tweeter that realistically can absorb on a continuous basis, around 5-10 watts (if you are lucky). A 20 watt amplifier will happily deliver 20 watts at any frequency up to about half of its power bandwidth and even at the upper end of its power bandwidth, it will still deliver 10w (-3dB), all before clipping. Most amplifiers have a power bandwidth above 40kHz.
Go play a 18kHz sine wave at 20 watts (just 12.65v RMS @8 ohms unclipped) into your 200 watt rated speakers and see how long your tweeters last. They won't even last 10 seconds.
Clipping can and often causes oscillations in amplifiers, often HF oscillations you don't even hear and poor little tweeters die instantly.
I am happy to demonstrate for you anytime how I can obliterate a tweeter in a 200watt speaker system with a 20w amplifier, clipping or not.
It is the shift in spectral energy distribution, by whatever method, be that clipping compression or oscillation that destroys tweeters and mids. Woofers don't suffer from that.
A speaker system rated at 200watts will often have a tweeter that realistically can absorb on a continuous basis, around 5-10 watts (if you are lucky). A 20 watt amplifier will happily deliver 20 watts at any frequency up to about half of its power bandwidth and even at the upper end of its power bandwidth, it will still deliver 10w (-3dB), all before clipping. Most amplifiers have a power bandwidth above 40kHz.
Go play a 18kHz sine wave at 20 watts (just 12.65v RMS @8 ohms unclipped) into your 200 watt rated speakers and see how long your tweeters last. They won't even last 10 seconds.
Clipping can and often causes oscillations in amplifiers, often HF oscillations you don't even hear and poor little tweeters die instantly.
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rifftrax
mix-meister
None of your points address anything that I was talking about, your post is figuratively one giant strawman argument.
I'll link this again, for everyone's sake so you can all see how mathematically inconsequential clipping-induced harmonics are to a tweeter:
http://sound.westhost.com/tweeters.htm
Also: http://sound.westhost.com/clipping.htm
Here's more just for fun, with additional actual data and test measurements (thank goodness for actual test measurements): http://www.bcae1.com/2ltlpwr.htm
And some data from someone else here @ audiokarma: http://www.audiokarma.org/forums/showthread.php?t=570917
Also, a good Rane article on it: http://www.adx.co.nz/techinfo/audio/note128.pdf
All of which invariably completely back up what I was saying.
One more thing. Let's say someone's argument for tweeter destruction is that some of this absurdly high frequency parasitic oscillation melts the voice-coil wire right off the bobbin. Well, your first problem here is that this sub-mhz oscillation isn't causing any excursion because the components are too high for the tweeter to even respond to. The other issue would be the point that this oscillation really just adds a total DC component to the overall wave, which is (tada) going to be exactly what accounts for your extra big bump in RMS voltage hitting the tweeter: http://education.lenardaudio.com/en/12_amps_3.html
Beyond that, being that copper melts at 1085° C (the most common voice-coil wire), you had better really hope you've not actually melted the wire. The likelihood that it was simply physically separated by shock is much higher.
Going even further, here's an article describing amplifier arcing, which results in peak voltages far beyond the available power rails:
http://www.w8ji.com/demonstation.htm
A scenario like this is far more likely than amplifier oscillation.
I'll link this again, for everyone's sake so you can all see how mathematically inconsequential clipping-induced harmonics are to a tweeter:
http://sound.westhost.com/tweeters.htm
Also: http://sound.westhost.com/clipping.htm
Here's more just for fun, with additional actual data and test measurements (thank goodness for actual test measurements): http://www.bcae1.com/2ltlpwr.htm
And some data from someone else here @ audiokarma: http://www.audiokarma.org/forums/showthread.php?t=570917
Also, a good Rane article on it: http://www.adx.co.nz/techinfo/audio/note128.pdf
All of which invariably completely back up what I was saying.
One more thing. Let's say someone's argument for tweeter destruction is that some of this absurdly high frequency parasitic oscillation melts the voice-coil wire right off the bobbin. Well, your first problem here is that this sub-mhz oscillation isn't causing any excursion because the components are too high for the tweeter to even respond to. The other issue would be the point that this oscillation really just adds a total DC component to the overall wave, which is (tada) going to be exactly what accounts for your extra big bump in RMS voltage hitting the tweeter: http://education.lenardaudio.com/en/12_amps_3.html
Beyond that, being that copper melts at 1085° C (the most common voice-coil wire), you had better really hope you've not actually melted the wire. The likelihood that it was simply physically separated by shock is much higher.
Going even further, here's an article describing amplifier arcing, which results in peak voltages far beyond the available power rails:
http://www.w8ji.com/demonstation.htm
A scenario like this is far more likely than amplifier oscillation.
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Not taking sides here (don't have the knowledge to do so!)...but did you mean, in your suggested experiment, to push an 18kHz sine wave at 20 watts into the crossover network of one's speakers, or directly into the tweeters? If into the crossover, wouldn't the tweeters get only some small portion of the total power (just a few watts)?
Regardless, if your demonstration successfully damaged the tweeters, the only logical conclusion that I could draw from it is that the tweeters got more power than they could handle. From what I can tell, most participants in this thread agree that pushing more power into a driver than it can handle - irrespective of the shape of the waverform - will damage it. I may well be missing a key point, but I don't see how this demo would link clipping to the damage.
Fundamentally, there seem to be two core schools of thought within this thread...one is that a clipped signal will (can), in and of itself, cause damage. The other is that damage is a function only of too much power...the shape of the waveform is not a factor. Yes, I understand there are some variations - most notably these three: 1) the "Rane" school (clipping of low frequencies lures us into cranking the volume to the point at which the tweeters are overpowered, if the amp is capable of producing more power than the speakers can dissipate), 2) the "clipping can cause an amp to misbehave" school (clipping may cause an amp to oscillate, arc or otherwise misbehave, which in turn may push excessive power into the speakers and damage them), and the 3) the "cliipping is DC, and DC damages speakers" contingent. The first two I would categorize into the "damage is a function of too much power" camp; in my view of the world, clipping is the direct cause of damage in neither of them. The third - the DC devotees - seems to be something of an outlier, and for now I'm going to discount this group (just to keep things simpler!).
In the "power causes damage" group, there is a second division of thought between 1) those who seem to think that a clipped signal "multiplies" the high-frequency energy (usually cited as a function of harmonics) significantly above the level at which it would be were the signal not clipped, and 2) those who believe that clipping does not cause any significant difference in high frequency power output. Both of these groups would agree that if the power going to the driver does not exceed the driver's capacity to dissipate that power, the driver will not be damaged.
I certainly may have made some errors in my distillation of clipping beliefs, but that's my best shot at summarizing where we are at this point. Oh, and one other thing...all seem to be able to agree that regardless of its potential for causing speaker damage (ranging from zero to absolutely!), anything more than minimal clipping definitely damages sound quality.
One last comment regarding my attempt to summarize things; I continue to see references to changes in spectral energy distribution (as a function of clipping). I don't think that anyone has of yet actually described what is meant by this term. I had initially thought that it was simply a "fancier" term for the "clipping causes excessive high frequency power" school of thought. However, I later noticed that some posters who seemed to be squarely in the "clipping causes no significant difference in high-frequency output" also made comments about the importance of changes in spectral energy distribution in understanding clipping and its effect(s). Color me confused on this part of the puzzle.
Carry on...and thanks for the continued participation and, at least in most cases, civility in your discourse and debate.
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Ahhhh... right from the first link you posted. By the way.. this is getting beyond the ridiculous. Geez... one can't believe the wave form analysis exercises text books put you through on the way to an engineering degree just so you'll have a running understanding of continual change taking place in dynamic situations including voltage and current relationships through a maze of inductance and capacitance from multiple sources interacting through multiple loads. The subject of this thread is elementary.
From your own link:
Power Distribution
A great part of the mystery is uncovered when we look at two aspects of music - the average versus peak power, and the energy distribution of typical music material.
It is commonly accepted (and quite valid) that music has a peak to average ratio of about 10-20dB. This means that if the signal is being amplified by a typical 100W amplifier, the amp's power rating limits the absolute maximum power to 100W (give or take a little). Since this is the peak, the average must be somewhat lower, and we will assume 10dB for the sake of convenience. Average power is therefore 10W or less at the onset of clipping.
This is not dynamic range per sé, but it is most certainly a part of the overall dynamic range of the music signal. The term 'dynamic range' usually refers to the very quietest up to the very loudest passages in a given piece of music. In some cases, there is no variation whatsoever - it starts loud, is loud in the middle, and (just to be different) finishes ... loud. The peak to average level may also be compressed, but it is difficult to reduce it to less than 10dB without it becoming flat and lifeless. If done incorrectly, it can simply become a jumbled mess with no intelligibility whatsoever (and no, I'm not going to take this to its logical conclusion and denounce various styles that may be classified as music to only a select few )
Most speakers are rated for a continuous power and an instantaneous power - the voice coil and to a lesser degree the suspension can withstand short bursts at much higher powers without damage. This does not imply that such power will be reproduced cleanly, and it will almost certainly be with a large increase in distortion. The peak power rating defines the maximum transient power the loudspeaker can handle without suffering electrical or mechanical (stress induced) damage.
Nearly all tweeters are rated to 'system power', and this will usually be quoted relative to a specific crossover frequency. A hypothetical tweeter may be rated at 100W system power when crossed over at 3,000Hz. The power that it can withstand is not 100W! Not at any frequency or for any duration.
Fig 1
Figure 1 - Power Distribution Chart
The above power distribution table is approximate (as must be the case), and applies for 'typical' music - whatever that may be. If we look at the case for a crossover frequency of 3kHz, we can see that 85% of the power is in the low frequency spectrum, and only 15% in the high frequencies above 3kHz. It is not difficult to deduce from this that the peak power to the tweeter will be in the order of 15W at full power from the amplifier, with the average at about 1.5W
This is the way the system was designed to be used, and as long as the power amp does not clip, all is well (well, almost - read on).
Overdrive Conditions
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
restorer-john
Addicted Member
If you feed 20 watts at 18kHz into the speaker sytem terminals, the crossover components will likely result in most of that appearing directly at the tweeter's voicecoil. Think of the corssover like a points system in a rail goods yard- it sends the signal to the appropriate driver/ drivers. In the case of a pure 18kHz tone- it will all go to the tweeter.
My experience with amps is they don't really care 'that much' about being overdriven. I used to drive them into a dummy load severely overloaded for periods of time looking for issues and they didn't blow up. Some of them have thermo devices that shut them down if they overheat but it takes a lot, more than you'd ever do with speakers connected unless a woofer voice coil shorted or the cap across the woofer shorted... or the speaker wires get shorted, which is something that happens and under that condition many home amps will be damaged if the volume is turned up. Also, running them at volume with too low impedance isn't good... like three sets of 8 ohm speakers in parallel, they don't like that. As far as simply overdriving them amps are pretty tough, they have to be to survive. Pretty good margins built into most of them. The ones I would be cautious with were the ones with IC outputs... the STK stuff. They used to be called Large Scale ICs. I don't even know if they use them anymore. Most of the units that used them were lower line but not always.
Excellent post, spicer (#187)...wonderfully articulated.
If one starts with an amp correctly rated at 15 watts via the FTC RMS method, I assume that it will produce 30 watts or thereabouts at full clipping. Accepting for this discussion that harmonics do indeed significantly increase high frequency energy, and based on your post, the tweeters would be getting approximately 7 watts of continuous power when this little amp is delivering a fully clipped signal. I believe that this is well within the capabilities of a good number of hi-fi tweeters. If so, this would seem to clearly demonstrate that clipping does not, in and of itself, cause damage? Would you find this conclusion to be correct? If not, what did I miss?
Another scenario, again using your post as its basis: This time, start with a 1000 watt amp (I don't even know if such a thing exists, but bear with me!). This amp would not be clipping at all (or only very minimally) when taken to the same output. But of course it would have destroyed most speakers before it could even get there.
These two scenarios seem to me to suggest that damage is caused by too much power, regardless of whether the signal is un-clipped, somewhat clipped or fully clipped.
The only situation in which I could see damage as being attributable to clipping - at least partially - is if high frequencies are indeed "multiplied" as an inherent characteristic of clipping (be it due to harmonics or some other phenomenon). In this situation, and with a tweeter which could have withstood the power level in the absence of the disproportionate increase in high energy, but is pushed beyond its limits in the face of that "extra" energy, I think I would be inclined to say that even though it is ultimately too much power that did the damage, it is clipping that pushed the driver over the edge and therefore clipping is the "cause" of the damage.
I would expect this particular scenario to be fairly limited, since it is by its very nature, quite situational...more of an exception than the rule.
In any case, it would seem that if we could resolve the question of whether or not clipping generates a "disproportionate" amount of high frequency energy (again, due to harmonics or some other mechanism), I for one, would have a clear answer to the question I posed in the poll.
I have seen quite a bit of evidence that, contrary to long-held beliefs on the subject, harmonics actually add very little in the way of high-frequency energy. However, as I am not an engineer (surprise!), and I did not stay at a Holiday Inn Express last night, I am unable to definitely determine the answer for myself. That said, I currently fall into the "harmonics have little effect" camp.
If one starts with an amp correctly rated at 15 watts via the FTC RMS method, I assume that it will produce 30 watts or thereabouts at full clipping. Accepting for this discussion that harmonics do indeed significantly increase high frequency energy, and based on your post, the tweeters would be getting approximately 7 watts of continuous power when this little amp is delivering a fully clipped signal. I believe that this is well within the capabilities of a good number of hi-fi tweeters. If so, this would seem to clearly demonstrate that clipping does not, in and of itself, cause damage? Would you find this conclusion to be correct? If not, what did I miss?
Another scenario, again using your post as its basis: This time, start with a 1000 watt amp (I don't even know if such a thing exists, but bear with me!). This amp would not be clipping at all (or only very minimally) when taken to the same output. But of course it would have destroyed most speakers before it could even get there.
These two scenarios seem to me to suggest that damage is caused by too much power, regardless of whether the signal is un-clipped, somewhat clipped or fully clipped.
The only situation in which I could see damage as being attributable to clipping - at least partially - is if high frequencies are indeed "multiplied" as an inherent characteristic of clipping (be it due to harmonics or some other phenomenon). In this situation, and with a tweeter which could have withstood the power level in the absence of the disproportionate increase in high energy, but is pushed beyond its limits in the face of that "extra" energy, I think I would be inclined to say that even though it is ultimately too much power that did the damage, it is clipping that pushed the driver over the edge and therefore clipping is the "cause" of the damage.
I would expect this particular scenario to be fairly limited, since it is by its very nature, quite situational...more of an exception than the rule.
In any case, it would seem that if we could resolve the question of whether or not clipping generates a "disproportionate" amount of high frequency energy (again, due to harmonics or some other mechanism), I for one, would have a clear answer to the question I posed in the poll.
I have seen quite a bit of evidence that, contrary to long-held beliefs on the subject, harmonics actually add very little in the way of high-frequency energy. However, as I am not an engineer (surprise!), and I did not stay at a Holiday Inn Express last night, I am unable to definitely determine the answer for myself. That said, I currently fall into the "harmonics have little effect" camp.
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Duh. I should have gone to bed two hours ago. Of course you are right. I was focused on the 20 watts.
JBL GUY
Addicted Member
I am reposting the link that shows quite clearly the amount of energy contained in the harmonics of square wave.
It clearly shows the amount of energy contained in the harmonics that make up the square wave. Again note that the the first harmonic that occurs after the fundamental frequency (the third harmonic or 3 times the frequency of the original or fundamental frequency) is almost 10 dB weaker than the fundamental frequency and the other harmonic frequencies continue to be weaker as their frequency increases.
If an amplifier is driven to less than full clipping, then the amplitude of the resulting harmonics is proportionally less.
The this video shows this in great detail.
This video shows an amplifier driven into partial clipping.
Note that the amplitude of the third harmonic is much smaller than the fundamental frequency (the spike on the spectrum analyzer is much shorter). And also note that the actual amplitude of the fundamental is actually larger than what is shown on the screen because the trace is actually going off of the screen at the top.
Also note as he points to the higher frequency harmonics, just exactly how much smaller they are.
Below are a couple of pictures taken from the video.
The first picture is of the clipped wave form.
The second picture is the resulting harmonics that are generated by this clipped wave form. Both pictures are of the same signal. Note the amplitude of the harmonics.
Kcbluesman, I hope this helps you and others understand this topic.
Attachments
Just two observations regarding the video -
Severe clipping was not shown for this demonstration, as you have noted. A spectral analysis @ 10 dB overdrive (750 watt in the case of this amplifier) would have been very interesting to see - as such is easily encountered.
Secondly, the test subject is a tube amplifier as opposed to SS. Clipping from tube equipment is said to not be nearly as deleterious as that from SS.
Severe clipping was not shown for this demonstration, as you have noted. A spectral analysis @ 10 dB overdrive (750 watt in the case of this amplifier) would have been very interesting to see - as such is easily encountered.
Secondly, the test subject is a tube amplifier as opposed to SS. Clipping from tube equipment is said to not be nearly as deleterious as that from SS.
mhardy6647
Lunatic Member
Just to be really clear -- failure to prove means... absolutely nothing vis-a-vis the "proveability" of a thing.
Consider, e.g., Fermat's "Last Theorem".
Fermat scribbled a note, in 1630, in the margin of a text relating to the proof of a rather simple mathematical "theorem" (which was not, technically, a "theorem" until proven). Proof eluded mathematicians until 1993.
http://mathworld.wolfram.com/FermatsLastTheorem.html
http://www-history.mcs.st-and.ac.uk/history/HistTopics/Fermat's_last_theorem.html
One may rest assured that some stuff has eluded empirical proof to date simply because no one has figured out how to proof said stuff.
Consider, e.g., Fermat's "Last Theorem".
Fermat scribbled a note, in 1630, in the margin of a text relating to the proof of a rather simple mathematical "theorem" (which was not, technically, a "theorem" until proven). Proof eluded mathematicians until 1993.
http://mathworld.wolfram.com/FermatsLastTheorem.html
http://www-history.mcs.st-and.ac.uk/history/HistTopics/Fermat's_last_theorem.html
One may rest assured that some stuff has eluded empirical proof to date simply because no one has figured out how to proof said stuff.
JBL GUY
Addicted Member
This is not correct because it does not take into account of the skewing (change in the relationship) of the spectral energy content of the music as spicer and I have mentioned.
The first picture is of the spectral energy distribution across the audio bandwidth of a song by Supertramp (no clipping and basic FM quality).
I am going to use round numbers for the numbers displayed for simplicity.
Look at the first picture below.
Note the relative levels of the signal at about 60 Hz, 700 Hz and 4.2 KHz.
The level of the signal at about 700 Hz is about 10 dB less than the signal at about 60 Hz and the level of the signal at about 4.2 KHz is about 20 dB less.
Of course the actual spectral distribution of the energy contained in music will vary from one song to another, but this is sufficient for my example.
The first signals to clip will be the low frequency signals. As the position of the volume control continues to be increased the levels of the higher frequencies will increase.
At full clipping the spectra of the music will resemble the second picture.
All signals will have the same amplitude. In your example that could mean that your little amplifier is actually sending 30 watts of power to the tweeter.
Keep in mind what is shown in this video. It shows the actual amount of harmonic energy in a clipped audio wave form.
What is shown in the two pictures below, may be what you refer to as compression in terms of this topic.
Again, and this is a fine differentiation, as can be seen from the above information, an amplifier can be driven into partial clipping without generating large amplitude harmonics that will damage a speaker driver.
But drive an amplifier hard enough into clipping and the amount of high frequency energy will increase because the spectral energy distribution is skewed (changed) because the gain of the amplifier continues to increase as the position of the volume control continues to increase. This coincides with the information as posted in the link to the Rane web site. Not because the clipped waveform is generating high amplitude harmonics.
Attachments
JBL GUY
Addicted Member
62caddy, the first video in that post shows the spectral content of a square wave, which is what one would have when an amplifier is driven into complete or severe clipping.
The second video shows an amplifier driven into partial clipping, a situation that it might be safe to say is more likely in real life, not that there might not be some that might turn all knobs all the way to the right.
Solid state or tube the math and science is basically the same.
Again the second video demonstrates the result of driving an amplifier into partial clipping.
This provides the answer to kcbluesman's original question. Clipping in and of its self is not going to cause damage to a speaker. There are instances where driving a amplifier into hard enough clipping may cause damage to a speaker for reasons that I have already posted. It is all about the power being supplied to the speaker.
The science is the science.
May I ask, please, how you would relate your comment to the clipping discussion?
If we drive 100 amplifiers into extreme clipping, but still producing less power than the speakers attached to them can dissipate, and we find that the speakers are undamaged, I would conclude that clipping does not inevitably lead to speaker damage. If instead we found that the speakers were damaged, I would conclude that clipping might have caused the damage.
Neither conclusion would be "proven", I guess...but I think that they would be logically valid.
62caddy, the first video in that post shows the spectral content of a square wave, which is what one would have when an amplifier is driven into complete or severe clipping.
The second video shows an amplifier driven into partial clipping, a situation that it might be safe to say is more likely in real life, not that there might not be some that might turn all knobs all the way to the right.
Solid state or tube the math and science is basically the same.
Again the second video demonstrates the result of driving an amplifier into partial clipping.
This provides the answer to kcbluesman's original question. Clipping in and of its self is not going to cause damage to a speaker. There are instances where driving a amplifier into hard enough clipping may cause damage to a speaker for reasons that I have already posted. It is all about the power being supplied to the speaker.
The science is the science.
Thanks JBL. Now if you could just throw me one more bone, please...what are those instances - briefly - in which heavy clipping may cause damage? I think that's where I got confused with your earlier posts - in which you seemed to give some credence to the spectral energy distribution/harmonics factor (a variable which you have now clarified to be insignificant as regards increased high frequency energy).
Feel free to just refer me back to specific posts. Thanks again!
EDIT: Never mind...just read your post #195, which I had overlooked.
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I think we are on the same page here.
62caddy, the first video in that post shows the spectral content of a square wave, which is what one would have when an amplifier is driven into complete or severe clipping.
The second video shows an amplifier driven into partial clipping, a situation that it might be safe to say is more likely in real life, not that there might not be some that might turn all knobs all the way to the right.
Solid state or tube the math and science is basically the same.
Again the second video demonstrates the result of driving an amplifier into partial clipping.
This provides the answer to kcbluesman's original question. Clipping in and of its self is not going to cause damage to a speaker. There are instances where driving a amplifier into hard enough clipping may cause damage to a speaker for reasons that I have already posted. It is all about the power being supplied to the speaker.
You are correct; hard clipping was present. I intended to mean a harder overdrive condition of say 10 dB over RMS. Not even 1 dB of overdrive was present in the demonstration.
However, I still maintain a 10dB overdrive is not that uncommon in real world conditions. It's really not that difficult to do - depending on loudspeaker efficiency relative to output capability of the amplifier.
JBL GUY
Addicted Member
You need to look at this video that I previously posted. You can not drive an amplifier harder than this.
This is a square wave and it is what you would have when an amplifier is driven into severe or complete clipping. Note the amplitude of the the harmonics.
Below is a picture of the signal on an oscilloscope and a spectrum analyzer.
To be clear, this discussion involves two things. One, the amount of energy in the harmonics of a clipped wave form and two, the reduction in the peak to average ratio of the music and the skewing of the spectral energy content of the music as shown in my previous posts.
Edit: Forgot the link.
