# Clipping revisited (with more evidence)



## Sam Spade (Mar 16, 2020)

*Clipping revisited (with more evidence)*
OK, here’s my claim and case again in a more clearly articulated way and supporting evidence. There is a shortage of proper scientific research into this as far as I can see, but lotsa matematical theory. I’m sorry if any of this is mansplaining.

Not to gloat, but these were the poll results:









Okat maybe it's gloating a bit  Note I didn't vote.

*Claim*

If you have 2 identical cars with two identical pairs in a *passive* speaker setup rated at 100 watts, and one car has a 200 watt amp, one has a 20 watt amp, which system is more likely to blow a driver? I’ll initially make this claim for home and car systems.
Note though, this conversation has made me wonder if the issue is more common in home hifi than car, because car hifi is often active, bandpass filters and electronic crossovers provide protection, and it seems to me that amp power is cheaper in car audio, relative to home systems. Therefore there are a whole segment of car audio setups where clipping is not a problem, except maybe for subwoofers. And there are many other ways to blow car speakers.
The concept of clipping and a smaller amp blowing a higher rated speaker is completely counterintuitive.
I don’t have all the answers and some of you have raised some really interesting points which I will respond to after this post
*Assumptions:*

Systems are passive
Amps don’t have thermal or clipping protection
Assuming a good install in a car, or a home hifi system, a 20 watt amp is more likely to blow 100 watt rated speakers than a 200 watt amp. This is because a smaller amp often won't be loud enough to satisfy the user and they will BE MORE LIKELY TO turn the volume up past 12 o'clock, and the amp will clip. Once an amp clips it squares off the waveform and holds the cone and voice coil stationary, with a current running through it, with no cooling from movement. This can often happen so fast you don't even hear the audible distortion or it cooks before you can turn it down.
Running a 200 watt amp into a 100 watt pair of speakers too hard will distort the speakers, but that distortion typically won’t blow the speakers immediately, and if you are listening, there is still movement for cooling, and if inclined you are likely to turn the volume down to below distortion levels. Distortion from too much current of a big amp doesn't hold the cone stationary, it takes a lot longer for the voice coil to heat up, and you have a much longer window of audible distortion to turn the amp down before the voice coil cooks.
*What is clipping?*
Wikipedia says: *Clipping* is a form of waveform distortion that occurs when an amplifier is overdriven and attempts to deliver an output voltage or current beyond its maximum capability. Driving an amplifier into clipping may cause it to output power in excess of its power rating (Crutchfield says this: _There's another, more complex reason voice coils burn when subjected to over-driven, clipped signals. A square wave carries twice the RMS power of a sine wave of the same amplitude (height). So not only is the signal telling the voice coil to pop into a position and sizzle, it's doing it with almost twice the power of the sub's maximum capacity. Usually, it's the glue holding the coil wire to the former that first melts under all the heat, and the coil crashes in its gap._) My argument about clipping doesn’t rely on clipping causing more output, just on DC current and stationary voice coils. But doubling the power would make it worse.
Why subwoofers blow: slam, bang, pop, and sizzle

The extra signal which is beyond the capability of the amplifier is simply cut off, resulting in a sine wave becoming a distorted square-wave-type waveform.

For example, The waveform outside the red line is what would be delivered in the absence of clipping, ie when the amp had enough headroom to deliver the signal: A Comparison of different methods for audio declipping










*This is a clipped sine wave note how it is squared off:*
When a wave is squared off the voice coil remains stationary and is receiving DC for a period of time, and voice coils are designed to operate on AC and be moving so there is cooling and they don’t overheat. I believe the combination of DC current and a stationary voice coil with no movement for cooling is the mechanism and how clipping fries a voice coil.










*Guitar clipping and valves*
@captainnbuffed Pointed out that many of the sounds produced by electric guitars are from clipping. He is spot on. But valve amps clip a lot more softly than solid state, are constructed to do this, and you get a cool distorted sound.

It is my understanding that valve amps clip much more softly than solid state, and are far less likely to destroy drivers.

*Anecdotal evidence*

This doesn't seem to matter if it is a tweeter or mid or bass. The first blown driver from a clipped amp I experienced was a 30 watt sansui amp which blew the woofer of a 150 watt rated sansui 3 way speaker. I know this cos I was a 16yo who thought a 30 watt amp could never blow up a 150 watt speaker and I turned it up to 11. *However, tweeters may be more likely to have built in protection meaning they are less likely to fry than mids/bass drivers.*
99% of hifi customers I sold gear to thought the same thing, ie a smaller amp could never blow up a higher rated speaker. We had numerous customers with small amps come back with blown drivers. I had the “beware that small amps can clip and destroy higher rated speakers” lecture for every customer. And it is completely counterintuitive.
This is completely uncontroversial in home hifi
*Class D*
Class D amplifiers can clip, and home speakers often have protection for tweeters, but not mid and bass drivers:

_So, at clipping levels, the digital power amplifier will output high levels of DC that will be fed to your vintage speakers & THAT (the DC) will be the death of them. The tweeter usually has a high-pass network which means that it has a series capacitor that will block DC but the woofer (& even the midrange) does/do not have a series capacitor so DC will be fed directly to the driver & it'll damage very quickly, if not immediately.
hope that this helps..... _


https://forum.audiogon.com/discussions/how-do-digital-amplifiers-clip



*Amps in general*
From Audio Science Review:

“I'm a big fan of Roger Sanders. He has a very measurement-based approach to his products and is of the view that amps _do_ sometimes sound different but not for the reason that most audiophiles think.

to quote:
_"Most audiophiles simply don't recognize when their amps are clipping. This is because the clipping usually only occurs on musical peaks where it is very transient, and does not occur at the average power level. Transient clipping is not recognized as clipping by most listeners because the average levels are relatively much longer than the peaks. Since the average levels aren't obviously distorted, the listeners think the amp is performing within its design parameters -- even when it is not.

Peak clipping really messes up the performance of the amplifier as its power supply voltages and circuits take several milliseconds to recover from clipping. During that time, the amp is operating far outside its design parameters, has massive distortion, and it will not sound good, even though it doesn't sound grossly distorted to the listener.

Instead of distortion, the listener will describe an amp that is clipping peaks as sounding "dull" (due to compressed dynamics), muddy (due to high transient distortion and compressed dynamics), "congested", "harsh", "strained", etc. In other words, the listener will recognize that the amp doesn't sound good, but he won't recognize the cause as simple amplifier clipping. Instead, he will likely assume that the differences in sound he hears is due to some minor feature like feedback, capacitors, type of tubes, bias level, class of operation, etc. rather than simply lack of power.

But his opinion would be just that -- an assumption that is totally unsupported and unproven by any evidence. Most likely his guess would not be the actual cause of the problem. "_

so, assuming the above makes sense (it seems to, at least to me) I'm wondering if it's possible or useful to measure this "transient" clipping?
It might provide a data point for readers. But I guess on the other hand, it may be pointless as we should probably just advise people to buy amps that are powerful enough not to clip”
does it make sense to test how amps behave when they clip?

This suggests that transient clipping may not destroy a driver.

*Amp specifications and clipping*
My Hertz HP802 stereo amps

*Output Nominal Power (RMS) @ 14.4 VDC, THD 1%:
2 Ch: *330 W x 2 (4 Ω)
*2 Ch: *550 W x 2 (2 Ω)
*2 Ch: *800 W x 2 (1 Ω)
*1 Ch: *1100 W x 1 (4 Ω)
*1 Ch: *1600 W x 1 (2 Ω)
*Output Power (RMS) @ 14.4 VDC, THD 10%:
2 Ch: *380 W x 2 (4 Ω)
*2 Ch: *630 W x 2 (2 Ω)
*2 Ch: *900 W x 2 (1 Ω)
*1 Ch: *1260 W x 1 (4 Ω)
*1 Ch: *1800 W x 1 (2 Ω)

This leaves me wondering, what THD constitutes clipping? Is it beyond 10% THD? I don’t know the answer to this. I don’t know how much clipped signal a driver can take before frying and I don’t know how to calculate it, I haven’t come across any data or calculation methodology on this.

*Other supporting info

Protection:*
If a loudspeaker is clipping, for example, the phenomenon can be aurally understood as distortion or break-up. Physically, if a loudspeaker remains in a clipping state for too long, there is potential for damage to occur due to overheating. However, many speakers have built-in precautions to avoid clipping, such as circuits that act like limiters.

The “soft-clip” circuit has been used in speakers since the ’80s, limiting the signal at the input stage. In the presence of an input signal that is, for instance, 10 dB higher than the speaker’s specified maximum, the soft-clip circuit kicks in to limit the signal and prevent clipping.









What Is Audio Clipping and Why Is It Important?


In the simplest sense, audio clipping is a form of waveform distortion. When an amplifier is pushed beyond its maximum limit, it goes into overdrive. The overdriven signal causes the amplifier to attempt to produce an output voltage beyond its capability, which is when audio clipping occurs.



producelikeapro.com





It is essential that a live sound engineer set the sound system in a way to avoid clipping because a failure to do so could cause damage to the loudspeakers. When a signal reaches the point of clipping, speaker cones do not move, as the clipped signal is essentially a DC signal for the duration that it exceeds the voltage rail boundaries. This causes all of the power from the amplifier to be used towards heating the voice coils instead of producing sound. In other words, during the times the signal is flattened, a loudspeaker is 100% efficient at converting power into heat.

Facts about clipping:

Any clipped signal can potentially damage a speaker. It does not matter whether the mixer, amplifier, or any other piece of audio equipment clips the signal in the system. Damage can occur even when the amplifier is not at full output.
Built in loudspeaker protection circuits cannot detect clipping and therefore cannot prevent damage from occurring because of clipping.
A driver can fail by using too small of an amplifier. If a loudspeaker is rated for greater power handling than the amplifier, then the speaker can burn out if the amp is driven into clipping.
The power handling specifications of a loudspeaker are only relevant for normal unclipped source signals.










*








What is Clipping?


To understand clipping, it is helpful to have a basic understanding of the electronic systems in which the audio signal travels.




mackie.com




*
More on first comment.


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## Sam Spade (Mar 16, 2020)

*Clipping revisited (with more evidence) Page 2*

In short, clipping is when the amplifier is unable to produce a clean sinusoidal waveform output, and instead produces a waveform with flat peaks, or in extreme conditions, square waveform output, which sends direct current to the speakers instead of the expected AC voltage, which in turn causes heat to build across the speakers' voice coils.

Causes for clipping in a car audio amplifier:

1. input sensitivity (gain) on the amplifier is set too high, which causes the line voltage from the head unit to over-drive the input stage of the amplifier.
2. Poor grounding of the amplifier, which causes inadequate current flow for the amplifier's power supply to produce the required power output.
3. Inadequate wire gauge (size) for the amount of current draw, and length of wire used for pos(+) and neg(-) power connections at the amplifiers.
4. The need for a larger alternator to supply the required current while the car engine is running, or more deep cycle batteries to do the same while the engine is off.
5. The possible additional need to upgrade the "big 3" connections in your car's engine bay.
6. Overheating of the amplifier itself, although this is very uncommon and usually indicates an installation or design flaw.
7. Over-equalization of the source signal before reaching the amplifier's input stage, which causes over-voltage in relation to the gain setting for the amplifier.

A common error in novice car audio installation is the tendancy for a person to compensate for a lack of amplifier power or overall desired volume by the audio system by cranking the gain setting on the amplifier all the way to maximum, using the gain like a volume knob. This is how people end up with problems like blown amplifiers, blown speakers, and feedback, distortion, alternator whine, and constant audible thumping from the subs even at low volume levels.
What is amplifier clipping?

*Amplifiers and Speakers:
Many people ask the question... Can my speakers handle this amplifier or will this amplifier blow my speakers. Well, the truth is that any speaker can be driven by any amplifier. The only time that there will be a problem is when the person operating the system becomes abusive. Most people (and I do mean most) drive their amplifiers well into clipping. I know what your thinking... I never drive my amp into clipping. Well, you must be one of the very few. Generally speaking, if you have friends who are impressed by high volume, you drive your system into clipping.

Clipping:
Unless you listen to your system from a distance, you cannot hear clipping distortion until it reaches extreme levels. I know you are thinking that you can probably hear even .5% distortion levels in music. Well, if you were listening to a test tone in an anechoic chamber at an 80 dB SPL on your best day, MAYBE. But... due to the design of the human ear, you cannot hear minimal distortion levels at higher SPLs. At any SPL above approximately 90 dB, your ears overload and cannot accurately convert the sound pressure to the electrical impulses which are sent to your brain. Since most amplifiers are capable of producing more than one watt of power and most speakers will produce at least 88 dB of sound pressure at one watt of input at one meter, it is very difficult to hear minimal distortion at 10, 20, 50 or more watts. If you honestly want to see if you're driving your system into clipping, play some familiar music at the highest volume that you would play it (when you are showing off for your friends) and step way away from you vehicle (with the doors open of course). You may have to turn off your bass amplifiers to listen for distortion in your 'highs'. I think you will be surprised at the levels of distortion that you hear. Now, be honest if you do this little experiment.

Bottom Line:
No one can tell you if you will blow your speakers with a given amplifier. They may be able to tell you whether or not a pair of speakers will be able to handle a given amount of continuous RMS power. But... since they don't know your listening habits or your ability to hear (or even be concerned about) distortion, they (in my opinion) cannot actually tell you if a given amplifier (with you at the volume control) will blow your speakers.*

Speaker Ratings



Crutchfield’s take:



*First, what’s a clipped signal?*
Clipping a signal, or squaring its waveform, occurs when the volume of a source signal exceeds the electronic capability of a circuit. Let's say our amplifier can't play a signal more powerful than what voltage V1 can produce. If we tried to increase the volume at the source, the amplifier wouldn't produce more voltage, it would distort the signal, eventually into the form of a square wave.








​
*Pop: A clipped signal tries to move the cone too quickly*

You will notice that the sides of the clipped signal are vertical. That means that the signal will try to move the sub's cone from all the way forward (point E) to all the way to the rear (F) in zero amount of time, travelling at the speed of infinity. Nothing travels that fast, and the sub either tears itself apart trying, or the flapping cone wobbles just enough to jam the coil in the magnet's voice coil gap, killing the sub.

*Sizzle: A clipped signal also tells the voice coil to hold still and heat up*

The other parts of a square wave, the top and bottom, are horizontal lines that represent the times the signal is telling the cone to stay all the way forward or all the way back. Current flowing through a stationary coil only heats up the coil, which doesn't even benefit from a cooling breeze due to movement. The coil usually burns through one or more of its windings, or heats up enough to deform its shape so that it jams in the magnet's voice coil gap.

There's another, more complex reason voice coils burn when subjected to over-driven, clipped signals. A square wave carries twice the RMS power of a sine wave of the same amplitude (height). So not only is the signal telling the voice coil to pop into a position and sizzle, it's doing it with almost twice the power of the sub's maximum capacity. Usually, it's the glue holding the coil wire to the former that first melts under all the heat, and the coil crashes in its gap.

*Distortion is the sub killer*
Low power and low volume will not hurt a sub – but distortion will. A clipped signal is a sub's worst enemy. It isn't loudness that destroys an under-powered sub, it's trying to get bass volume by turning up a distorting signal that does it.

Clipping and tweeter damage a more mathematical explanation:

Under normal circumstances, most music does not contain high sustained levels of high frequency power. Hence in normal use, all being well, the relative delicacy of the tweeters does not matter. Unfortunately, despite this general observation, sometimes tweeter units do fail. The question is, why?
















Amplifier clipping and tweeter damage

*And pro Audio*
This is a lucid read. I won’t paste it all but try the URL for a thorough explanation.

We often get asked what size power amplifier we recommend for a particular passive (i.e., non-powered) loudspeaker model. In general, the recommendation is that you should pick an amplifier that can deliver power equal to twice the speaker’s continuous average power rating. This means that a speaker with a nominal impedance of 8 ohms and a continuous average power rating of 300 watts, for example, would require an amplifier that can produce 600 watts into an 8 ohm load.

Why is it that we recommend a power amp that’s twice as big as the speaker? The short answer is that a quality professional loudspeaker can handle transient peaks in excess of its rated power, if the amplifier can deliver those peaks without distortion. Using an amp with some extra headroom helps assure that only clean, undistorted power get to the loudspeaker.

For a more complete answer, JBL published a *Tech Note* a few decades ago that goes into more details about the drawbacks of using too small of a power amplifier. It’s called “Danger: Low Power.” The principle is as valid today as when the Tech Note was first introduced. However, we wanted to update and modernize the Tech Note’s content because it had references to types of ancillary equipment that are no longer in common use today, and because it did not mention some more common items that are utilized in today’s sound systems. An example is the addition of an explanation of the shortcomings of relying too much on limiters for protection of the loudspeakers and the misimpression that adding a limiter now makes it okay to use a smaller amplifier. Here is an advanced view of the upcoming Tech Note revision:

The supply rails in an average 50 Watt per channel domestic amplifier will be approx 30V. There are 2 supply rails +30V and -30V. This is correctly stated as + - 30V. The difference between the supply rails is 60V. The speaker is connected by one transistor to one supply rail at a time. The maximum Voltage to the speaker can be no greater than 30V. That is +30V or -30V at any one point in time.

*Clipping* If the audio signal is driven into the rail supply, then the speaker is held at 30V for a longer period of time. The more the sine wave is driven into clipping the more it will change shape toward a square wave. The RMS formula (peak V x 0.707) for a sine wave, no longer applies, because the Voltage into the speaker will remain at 30V, flipping directly between +30V or -30V, dependant of frequency. 30V x 30V / 8R = 112 Watts (100 Watts approx). We can now see that power to the speaker can be doubled by simply driving the amplifier into extreme clipping or overload. Many guitar players drive their amps in clipped distortion 100% of the time. Guitar amplifiers have multi stage high gain pre-amplifiers to enable the output to be easily driven into clipping. The distorted guitar sound now remains at a constant level, and is described as 'sustain'.


















New Insights into the Dangers of Using Power Amplifiers That Are Too Small –
 

We often get asked what size power amplifier we recommend for a particular passive (i.e., non-powered) loudspeaker model. In general, the recommendation is



pro.harman.com





*And clipping can have some advantages*




























A specific type of distortion. If a signal is passed through an electronic device which cannot accommodate its maximum voltage or current requirements, the waveform of the signal is sometimes said to be clipped, because it looks on a scope like its peaks have been clipped off by a pair of scissors. A clipped waveform contains a great deal of harmonic distortion (see WFTD archive harmonic distortion) and often sounds very rough and harsh. Clipping is what typically happens when an audio amplifier output is overloaded or its input over driven.

Interestingly, light to moderate clipping does not usually reduce the intelligibility of some signals, especially speech. In fact, it has been shown that clipped speech is easier to understand than normal speech in noisy environments. A probable reason for this is the increased high frequency content that accompanies this type of distortion, which can make a signal stand out more among other sounds and noises. Aphex and some other companies have been using this principle for years in their “exciter” type products. By adding the right amount of distortion at the right frequencies a signal will sound almost clearer and more distinct amidst other sounds, thus standing out more in a mix.









Clipping - inSync


A specific type of distortion. If a signal is passed through an electronic device which cannot... Read more »




www.sweetwater.com


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## Sam Spade (Mar 16, 2020)

@jtrosky _Not enough information given. The biggest determining factor (IMO) would be how loud the system is going to be played. _

yup not enough information and you are right about how loud.


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## Sam Spade (Mar 16, 2020)

@gijoe _Here's the thing about clipping. Clipping damages speakers due to excess power. The speaker experiences more power over a period of time than it would with a clean wave, but the shape of the wave itself isn't what damages a speaker, excessive power does. _
The research I've done suggests both are causes. 

_Some clipping is perfectly harmless, and most systems are set up so that there is a bit of clipping when playing the system loudly. Depending on the frequency, some clipping isn't even audible. _
agree entirely


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## Sam Spade (Mar 16, 2020)

@miniSQ _Please post some plots. 

done. _


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## Sam Spade (Mar 16, 2020)

@gijoe _Yes, but a clipped signal from a 20 watt amp isn't going to produce enough power to hurt a speaker rated for 5x that much power._
I don't know about that, I don't know the tolerances

_People seem to think that clipping creates an infinite amount of power, and that clipping will destroy any speaker that is connected, but a clipped signal at from a 20 watt amp still isn't going to damage a speaker that is rated to handle 100 watts continuously. _

Clipping doesn't create an infinite amount of power, and Crutchfield says this: 
(Crutchfield says this: _There's another, more complex reason voice coils burn when subjected to over-driven, clipped signals. A square wave carries twice the RMS power of a sine wave of the same amplitude (height). So not only is the signal telling the voice coil to pop into a position and sizzle, it's doing it with almost twice the power of the sub's maximum capacity. Usually, it's the glue holding the coil wire to the former that first melts under all the heat, and the coil crashes in its gap._) My argument about clipping doesn’t rely on clipping causing more output, just on DC current and stationary voice coils. But doubling the power would make it worse.
Why subwoofers blow: slam, bang, pop, and sizzle


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## Sam Spade (Mar 16, 2020)

@JCsAudio _Remember the days when your car factory radio didn't have factory EQ or HP filters on the midbass and if you turned it up all the way it was all distorted, yet if you listened to it like that for hours it didn't blow the speakers? It just didn't have enough power to exceed the thermal limits of the speaker coil or damage it mechanically either. That was 8 to 20 watts clipping! Every teenager in the neighborhood who got ahold of their parents 1983 Oldsmobile Cutlass Supreme did that, lol._

That's really interesting anecdotal evidence and changes my position. There must be a threshold in at least some cases where a clipped amp will not blow a particular speaker


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## Sam Spade (Mar 16, 2020)

@miniSQ_ I saw this just now...Sam has added andy's comment to the "dumbest things ever heard in car audio. We have a real Koontz on our hands with this DA.

Sam says: my contribution from today in a conversation about whether a 20 watt or 200 watt amp is more likely to blow a 100 watt speaker: "If the assumption is that the speaker rating is accurate and that the amplifiers will be driven as hard as they can possibly be driven, the the answer is simple. The 20 watt amplifier will NEVER EVER blow the speakers. Ever. No matter what. Ever._

I quite liked Koutz, he was entertaining 

This was out of line and poor judgment. I have sincerely apologised on the other thread and do so here again.


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## Sam Spade (Mar 16, 2020)

@jtrosky _It sounds like amp clipping can only damage a speaker if the amp RMS rating is equal-to or higher than the speaker RMS rating and you drive the amp into clipping. Is that correct?_

In my experience and as a homefi salesman I have seen small amps blow large speakers
_
What if the amp and speaker ratings are closer than in Sams example, like 90W amp and 100W speaker, could clipping from the 90W amp damage a 100W rated speaker (being that the ratings are much closer than in Sams example)?_

I tried to find this out, no luck.
_
I'm genuinely curious because there is obviously a lot of conflicting info out there..._

Yes there is which is why I started the thread in the first place.


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## Sam Spade (Mar 16, 2020)

@JCsAudio S_hould enthusiast worry about amplifiers clipping in car audio, and especially with an active setup? I think no except for the mono block amplifier and maybe the amplifier driving the mid-bass driver where it actually matters. Set your HP filters correctly according to your speaker drivers capabilities and be careful with the subwoofer and you will be fine._ 

You have probably nailed it here, except I suspect many setups still have passive xovers. we could do a poll 🤣🤣🤣🤣


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## Sam Spade (Mar 16, 2020)

@Holmz _The humour is OK._
Thank you for being gracious

_The idea that one needs 160W on a tweeter channel because.. "HEADROOM" sort of gets me spun up.
1 dB of headroom is the same as 30dB of headroom, and that assumes slight clipping is bad... which is also somewhat debatable._

Agree entirely.


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## Ge0 (Jul 23, 2007)

Sam. I see you are taking the other threads troll arguments personally. Back off man. Take it for what it is. This is consuming you unnecessarily. We've had some good conversations together. Sit back and relax. It's OK to collectively disagree even though your original intent was obvious...

Ge0


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## gijoe (Mar 25, 2008)

Good god man, nobody wants to read all of that. So, you win, I guess...


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## DavidRam (Nov 2, 2014)

gijoe said:


> Good god man, nobody wants to read all of that. So, you win, I guess...



He just loves hearing himself speak, or reading himself write, or writing himself right. I read a proverb or saying recently (can't remember where), that said something like _the man who speaks the most is the biggest fool_. I thought of Sam when I read it.


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## Sam Spade (Mar 16, 2020)

Ge0 said:


> Sam. I see you are taking the other threads troll arguments personally. Back off man. Take it for what it is. This is consuming you unnecessarily. We've had some good conversations together. Sit back and relax. It's OK to collectively disagree even though your original intent was obvious...
> 
> Ge0


Thanks geo, this response has been developing when i had some spare time over a few days. I just wanted to put my case clearly which i didn't do the first time.It's all ok, I read, research and write for a living. Some people put some good points which made me question something I believed was certain. And it's only courteous to respond to those, and they made me curious. Turns out, as far as I can tell, that clipping destroys speakers less than I thought but a small amp can destroy a higher rated driver when clipped. 

I was after some proper scientific research but found none so it's all anecdotal and expert claims though.


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## Sam Spade (Mar 16, 2020)

gijoe said:


> Good god man, nobody wants to read all of that. So, you win, I guess...


It isnt about winning gijoe, its about whats true. I would have just admitted it if i was wrong. But i learnt stuff researching it. Clipping can but doesn't always trash spoeakers


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## Sam Spade (Mar 16, 2020)

DavidRam said:


> He just loves hearing himself speak, or reading himself write, or writing himself right. I read a proverb or saying recently (can't remember where), that said something like _the man who speaks the most is the biggest fool_. I thought of Sam when I read it.


So you do read dave?


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## 156546 (Feb 10, 2017)

OK. Here's how it works. I have no idea how to post pictures here anymore. 

When you clip the wave, harmonics are added. Those harmonics are MULTIPLES of the fundamental frequency, so they are higher frequency content added to the fundamental. 

We use pink noise (or some other similar noise shape) in testing speakers because it is similar to the frequency distribution in music. A pinking filter is a 3dB/oct low pass filter. 3dB is 2X power. 

So, if we calibrate our amplifier to provide the speaker's rated power using a sine wave, when we turn on the pink noise that's recorded at 0dB, only 20Hz will be reproduced at that power--let's call it 20 watts. 

At 40Hz, the level will be10 watts. At 80, 5 watts. At 160, 2.5 watts. At 320, 1.25 watts. At 640, .625 watts. At 1280, 0.3125 watts. At 2560, 0.15625 watts. At 5120, 0.078125 watts. at 10240, 0.0390625 watts. And at 20k, it will be 0.01953 watts. 

So, in our speaker with a passive crossover at 2k, the tweeter only has to handle about 0.2 watts for our speaker to have a rating of 20 watts. 

When you clip the **** out of the amplifier so that the wave is square, all of that high frequency content that's added passes right through the crossover and nukes the tweeter. Because the tweeter is designed to handle on the part of the spectrum with program material for which is is responsible. 

So, you'll kill the tweeter. But the woofer will play forever. 

With the 200 watt amplifier driven to it's full 200 watts, the tweeter will get 10X the power, or about 2 watts. If the tweeter is designed to handle .2 watts, then the 200 watt amplifier will kill it playing music without any clipping. It will also, if driven to its full power, probably kill the woofer because it will provide 10X the power the speaker is rated to handle. 

So, if we're talking about multiway speakers with passives, driven by the same amplifier channel, then the tweeter gets killed in both scenarios. If we're talking about blowing up a single driver with an amplifier that's less than about 2X the speaker's ACTUAL power handling rating, then the horrendously clipped 20 watt amplifier is no problem.


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## Holmz (Jul 12, 2017)

Sam,
You have fire in your eyes and passion, but other than some mania, I just see some claims and discussion about what it is.

One could work this out in an hour in a high school electronics lab. And most everyone says do not use a scope, just tune by ear.

One can ease off the throttle a bit, on some of these threads?


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## 156546 (Feb 10, 2017)

And this is why you MUST disconnect the tweeter when you set the gains with the scope or the DD-1 and a 0dB sine wave track--because the tweeter WON'T handle and was never intended to handle 100 watts continuous despite the rating. It's intended to handle a portion of a particular spectrum when the level of the loudest part of the spectrum (20Hz) has been calibrated at 100 watts.


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## Holmz (Jul 12, 2017)

I have the big 4-ohm resisters...

But the idea of a plot showing a sinewave clipping at 40-Hz, is a different beast to a 3-kHz sinewave riding on top of a 50-Hz swell. The square edged 3kHz will be spraying out harmonic that would confuse a bat.

So the simple drawing of a sinewave is somewhat overly simple compared to full range music in a passive XO system.


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## Sam Spade (Mar 16, 2020)

Holmz said:


> Sam,
> You have fire in your eyes and passion, but other than some mania, I just see some claims and discussion about what it is.
> 
> One could work this out in an hour in a high school electronics lab. And most everyone says do not use a scope, just tune by ear.
> ...


I don't have mania unfortunately, it's quite fun.

I was just trying to find some quality research papers which I didn't, and show some respect to the good and interesting points made by other people. And @GotFrogs points makes me wonder about @JCsAudio's point about _1983 Oldsmobile Cutlass Supreme_ being driven to clipping by teenagers all over the US. Maybe they had full range drivers but no tweeters so they could take the thrashing?

So what you are saying @GotFrogs is that clipping blowing mid/woofer speakers is an urban myth, and the home hifi drivers, other than tweeters, that came back dead with typically 30-60 watts RMS into 8 ohms, driving 100-200 watt speakers was likely some other fault?


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## Sam Spade (Mar 16, 2020)

Holmz said:


> Sam,
> You have fire in your eyes and passion, but other than some mania, I just see some claims and discussion about what it is.
> 
> One could work this out in an hour in a high school electronics lab. And most everyone says do not use a scope, just tune by ear.
> ...


The reason I set off scouring the internet and then summarising it is there were many points that made me question my understanding. And it's only courteous to respond to those, and they made me curious. 

I research, analyse and write for work so it's no big deal but my intention is to be thorough, not fanatical. 

I now have a much better idea what is going on, in particular thanks to @GotFrogs, and realise my initial view was simplistic.

One thing i'm sure of, in home hifi, people often don't buy enough watts to do their speakers justice. I expect this is especially true with multi speaker home theater systems. And I suspect they are listening to distorted output a lot of the time. A couple of authors claim that is true for a lot of car systems as well. 

BUT This seems less likely in car hifi as relative to the cost of speakers, amp watts seem cheaper. As long as people spend the cash.


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## lingling1337 (Oct 14, 2019)

Sir, this is a Wendys


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## 156546 (Feb 10, 2017)

Here's my explanation with some pics.

Pink Noise, White Noise and Why Your Tweeters Never Get 150 ...


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## Holmz (Jul 12, 2017)

When you have the clipping like is shown in the cartoon, there is no DC being sent to the tweeters.
What is happening is that the square wave at say 1000 Hz has a frequency domain representation that is no longer a 1000- tone, but the whole harmonic expansion to infinity... but mostly even harmonics at 2,4,8 and the odd harmonics and 3k, etc.

Hence the clipping can be approached with the low frequency content in the music, and then the MR and higher frequency content is like picket fence on top of that, And it slaps against the rails and turns it into a fire hose of high frequency harmonics of a a square wave.

In a car people normally use a DSP, and there is no clipping of any of the musical content in the 3-20 kHz range... unless they jack up the gain structure. 

In a home system it is often common to have a sub woofer added, and a highpass filter installed on main speakers to remove those big low frequency swells ans rolling waves.
Even my 35 year old speakers have bi-amp inputs on their passive XO inputs, and there is a sub that is just plug-n-play to relieve the low frequencies off of the main speakers.

All that said, even say going to a 250W amp, someone will still crank it to 11.
That part is just common and why we either have a gain knob or keep the children away from the stereo.


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## dumdum (Feb 27, 2007)

Sam Spade said:


> I don't have mania unfortunately, it's quite fun.
> 
> I was just trying to find some quality research papers which I didn't, and show some respect to the good and interesting points made by other people. And @GotFrogs points makes me wonder about @JCsAudio's point about _1983 Oldsmobile Cutlass Supreme_ being driven to clipping by teenagers all over the US. Maybe they had full range drivers but no tweeters so they could take the thrashing?
> 
> So what you are saying @GotFrogs is that clipping blowing mid/woofer speakers is an urban myth, and the home hifi drivers, other than tweeters, that came back dead with typically 30-60 watts RMS into 8 ohms, driving 100-200 watt speakers was likely some other fault?


Home audio drivers aren’t all 100-200wrms drivers, your not even getting facts right... for example my satoris are 40wrms... so 20watts fully clipped would be on the limit for them...

your sweeping generalisations are hilarious... sorry but you’ve made loads of jumps to conclusions and are now being shown up


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## Sam Spade (Mar 16, 2020)

dumdum said:


> Home audio drivers aren’t all 100-200wrms drivers, your not even getting facts right... for example my satoris are 40wrms... so 20watts fully clipped would be on the limit for them...
> 
> your sweeping generalisations are hilarious... sorry but you’ve made loads of jumps to conclusions and are now being shown up


Well my dynaudio image 1 two way bookshelf speakers are rated 60wpc and my dali suite 3.5s are 200 wpc. 

And the original thread was posed as a question. Surely the forum should be a learning experience dum dum?


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## dumdum (Feb 27, 2007)

Sam Spade said:


> Well my dynaudio image 1 two way bookshelf speakers are rated 60wpc and my dali suite 3.5s are 200 wpc.
> 
> And the original thread was posed as a question. Surely the forum should be a learning experience dum dum?


That doesn’t mean the tweeter is rated at 60wrms...

the Dali suite 3.5 will likely have resistors in series with midrange and tweeters and those tweeters will be rated around 10-20watts for reasons given above, and the power is shared between the midbass units which look like 8” midbass so 80-100w is not surprising, hardly a fleeting example of all home audio drivers... note drivers... not speaker systems overall...

so I’m yet to see these examples of 1-6” drivers most use rated at 100-200w still... maybe morel with their hexatech his massive voice coils, but even then they are rated as 50-100w rms continuous and way higher peaks
Again, this makes what you’re saying a stretch at best and like you are making the case fit your argument more than actual facts to prove it...


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## Sam Spade (Mar 16, 2020)

dumdum said:


> That doesn’t mean the tweeter is rated at 60wrms...
> 
> the Dali suite 3.5 will likely have resistors in series with midrange and tweeters and those tweeters will be rated around 10-20watts for reasons given above, and the power is shared between the midbass units which look like 8” midbass so 80-100w is not surprising, hardly a fleeting example of all home audio drivers... note drivers... not speaker systems overall...
> 
> ...


I never meant to imply individual drivers ratings i was intending to mean the total wattage rating of a speaker with a passive crossover

But yes the three 8 inch midbass drivers work really well i think it is a sealed/bass reflex combo and the cabinets are the nicest furniture in the house. Minus 3db at 32hz. Never been tempted to add a sub. Running off a 200wpc into 8 ohms rotel RB1080.


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