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post #181 of 637 Old 09-09-2013, 06:05 AM
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Originally Posted by OllieS View Post
 
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Originally Posted by kbarnes701 
If you push your amp into clipping it will have a progressively deteriorating sound quality. It will start by just sounding 'uncomfortably loud'. After a short while you will have the overwhelming feeling that you need to turn the volume down.

If the symptoms of a clipping amplifier are uncomfortably loud sound then I'm sure one could use the same symptoms and misdiagnose the problem for something else entirely. Like say the room acoustics. Perhaps the reflections in the room at a given volume are so harsh that it sounds too loud at that setting, so instead of addressing the acoustics in the room, they decide to buy a bigger amplifier.

I guess what I'm trying to say is that you could probably have more than one symptom that may also reach similar conclusions - re uncomfortably loud. I'm not a technical guy, but I imagine you would probably need switching gear that could toggle between two amplifiers, one a lesser amp and a more powerful model otherwise it may just be my brain playing tricks on me. biggrin.gif Either that or some way of measuring the signal at that volume, as arny described.

I don't know, what do you think? Thanks again for your explanations in the thread, I'm glad we could all have a civil discussion about this.

 

There are several possible causes of distorted sound - Arny has listed them in his post above. I was just responding to the poster's question where he asked for a simple description of what clipping sounds like. An experienced listener will probably be able to distinguish between the sound of an amp clipping and the sound of an overly-reflective room causing distortion, but for an inexperienced listener I can easily believe they might sound the same.  But remember that 'sounding loud' was only one of the possible causes I gave.  Arny has explained how to test for sure in his last post above. It is bound to require some technical ability to carry out such a test of course.

 

Again, the bottom line really is that if your system sounds good at the SPLs you want, then you are basically all set.

 

EDIT: if you have a computer that can play sound files, why not take Arny up on his offer of providing some safe downloadable files that demonstrate what clipping sounds like. 



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post #182 of 637 Old 09-09-2013, 06:42 AM - Thread Starter
 
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Originally Posted by kbarnes701 
EDIT: if you have a computer that can play sound files, why not take Arny up on his offer of providing some safe downloadable files that demonstrate what clipping sounds like.

Definitely. I'm always willing to learn, so I'm up for it.
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post #183 of 637 Old 09-09-2013, 06:48 AM
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Quote:
Originally Posted by kbarnes701 
EDIT: if you have a computer that can play sound files, why not take Arny up on his offer of providing some safe downloadable files that demonstrate what clipping sounds like.

Definitely. I'm always willing to learn, so I'm up for it.

 

I am sure he will be happy to oblige. Nothing like hearing it for yourself.



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post #184 of 637 Old 09-09-2013, 07:47 AM
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Originally Posted by OllieS View Post

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Originally Posted by kbarnes701 
EDIT: if you have a computer that can play sound files, why not take Arny up on his offer of providing some safe downloadable files that demonstrate what clipping sounds like.

Definitely. I'm always willing to learn, so I'm up for it.

Here are the public links to my Dropbox.

https://dl.dropboxusercontent.com/u/36129341/mustang.loop.wav

https://dl.dropboxusercontent.com/u/36129341/mustang.loop%206%20dB.wav

https://dl.dropboxusercontent.com/u/36129341/mustang.loop%2013%20dB.wav

https://dl.dropboxusercontent.com/u/36129341/mustang.loop%2020%20dB.wav

The percentages in the names represent how many dB of clipping. IOW the 6 dB file has half the peaks cut off, the 13 dB file has a little more than 3/4 of the peaks cut off, and the 20 dB file has 90% of the peaks cut off.

You will probably be surprised how much clipping has limited audibility. If you don't hear the mud in the 20 dB file, beg borrow or steal new ears! ;-)

They should stay up until I need the space.
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post #185 of 637 Old 09-09-2013, 08:44 AM - Thread Starter
 
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Thank you very much arnyk for the links! I'll take a look when I get home and can spend some time going through it. Thanks again.
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post #186 of 637 Old 09-10-2013, 03:35 AM
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Thanks for those sounds clips, Arny. If I didn't know what I was listening for very closely, I'd have a hard time to find a clipping noise on the 6-13 db file. The 20 db is very noticeable, for sure.
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post #187 of 637 Old 09-10-2013, 06:26 AM - Thread Starter
 
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Arny, or anyone knowledgeable, at what point normally does an amp clip in terms of distortion level? All amps can deliver more than rated power if you up the distortion, which I understand now, but at what point does the clipping commence?

And the clipping itself can produce even more power to be delivered at an even higher distortion. Earlier on you guys mentioned clipping can result in double the rated power - is that the clipping on it's own, or is that the total amount of power the amp can possibly deliver under the worst of circumstances?

Just trying to put this into perspective. An amp rated at 100 watts at 0.1% can probably deliver 150 watts at 20% distortion. So is clipping sort of like 80% distortion? 100%? Thanks
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post #188 of 637 Old 09-10-2013, 10:39 AM
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Originally Posted by arnyk View Post

an amplifier that is actually clipping at the moment sounds bad. Clipped music is distorted music.

This is the key point. Once an amplifier is clipping so badly that it adds enough HF content to damage your tweeters, the music would sound horribly distorted. Who listens like that?

--Ethan

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post #189 of 637 Old 09-10-2013, 10:41 AM
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Originally Posted by OllieS View Post

at what point does the clipping commence?

Amplifiers can clip when asked to output either more volts or more current than the power supply can provide. Which limit is reached first depends on the impedance of the loudspeakers.

--Ethan

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post #190 of 637 Old 09-10-2013, 11:12 AM
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Originally Posted by Cvetan1 View Post

Thanks for those sounds clips, Arny. If I didn't know what I was listening for very closely, I'd have a hard time to find a clipping noise on the 6-13 db file. The 20 db is very noticeable, for sure.

 

The onset of clipping isn't necessarily obvious as clipping. Like I said earlier, at first it might just sound uncomfortably loud, or it might cause listener fatigue and you just want to stop listening, without necessarily knowing why. As Ethan says, when clipping is really obviously clipping, and at a level likely to FUBAR your speakers, you would have long since stopped listening!



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post #191 of 637 Old 09-10-2013, 11:40 AM
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Originally Posted by Ethan Winer View Post

This is the key point. Once an amplifier is clipping so badly that it adds enough HF content to damage your tweeters, the music would sound horribly distorted. Who listens like that?

--Ethan

Not to be too flip, but: drunk people.

Not only ae they less attentive to the sound of the distortion, but alcohol makes things sound quieter so they want to turn it up to get the same sensation they had before that first couple of beers . . .
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post #192 of 637 Old 09-10-2013, 11:44 AM
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Amplifiers can clip when asked to output either more volts or more current than the power supply can provide. Which limit is reached first depends on the impedance of the loudspeakers.

--Ethan

Well, I don't mean to threadjack this one any further than I did earlier and will link to another thread which I did the same with in regard to the Frequency Response Curve of the the Klipsch RF-7IIs. The MFG rates them as "8 Ohm Compatible" with an impedance of 101 dB/1 meter/2.83 volts, but it's obvious they are 4 Ohm speakers if judged by the IEC method of specifying nominal loudspeaker impedance: http://www.avsforum.com/t/1412510/klipsch-rf7-ii-measurements

I have had a few helpful comments but am trying to find if Audyssey is helping them sound great or having a power supply rated to drive 4 Ohm speaker is more important...Others say an external amp is a must. {EDIT: I am not the OP on that thread and my comments are at the end, but the charts are in the beginning.}
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post #193 of 637 Old 09-10-2013, 12:26 PM
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This is the key point. Once an amplifier is clipping so badly that it adds enough HF content to damage your tweeters, the music would sound horribly distorted. Who listens like that?

--Ethan

Not to be too flip, but: drunk people.

Not only ae they less attentive to the sound of the distortion, but alcohol makes things sound quieter so they want to turn it up to get the same sensation they had before that first couple of beers . . .

 

Absolutely. I have had, on two occasions, at parties, someone in the 'not entirely sober' category, wind the volume up on my music system, which has resulted in a blown driver. Not only does alcohol make people impervious to loud sounds it seems, but also to horrific pre-death distortion. Nowadays, I take steps to ensure this cannot happen but in the good ol' days we had fewer resources at our disposal for controlling maximum SPLs.



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post #194 of 637 Old 09-10-2013, 03:22 PM
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Originally Posted by kbarnes701 View Post

Absolutely. I have had, on two occasions, at parties, someone in the 'not entirely sober' category, wind the volume up on my music system, which has resulted in a blown driver. Not only does alcohol make people impervious to loud sounds it seems, but also to horrific pre-death distortion. Nowadays, I take steps to ensure this cannot happen but in the good ol' days we had fewer resources at our disposal for controlling maximum SPLs.

handguns just aren't as popular over there, are they? smile.gif

just to be clear, "that's a joke, son"
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post #195 of 637 Old 09-10-2013, 03:33 PM
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Originally Posted by Zen Traveler View Post

Well, I don't mean to threadjack this one any further than I did earlier and will link to another thread which I did the same with in regard to the Frequency Response Curve of the the Klipsch RF-7IIs. The MFG rates them as "8 Ohm Compatible" with an impedance of 101 dB/1 meter/2.83 volts, but it's obvious they are 4 Ohm speakers if judged by the IEC method of specifying nominal loudspeaker impedance: http://www.avsforum.com/t/1412510/klipsch-rf7-ii-measurements

I have had a few helpful comments but am trying to find if Audyssey is helping them sound great or having a power supply rated to drive 4 Ohm speaker is more important...Others say an external amp is a must. {EDIT: I am not the OP on that thread and my comments are at the end, but the charts are in the beginning.}

assuming they function like 4 ohm speakers, they are rated 25 dB more sensitive than my former Maggies (which measure like a four ohm resistor except the higher impeande at the crossover). I listen no louder than ten dB below reference and never had a problem driving them with my Denon 989, Arcam 250 or little Bryston 2B Lp. IOW, unless you sit very far away in a dead room or listen really really loud, I'd guess a decent receiver can drive them well past my loudness limits. YMMV.

FWIW there's a lot of chatter on the net about how the Maggie 1.6Q requires a lot of power before it makes bass, or sounds good, or whatever. My semi informal testing demonstrated zero bass extension difference, either measured or subjectively, between a 50 WPC amp and a 250 WPC amp driving the Maggies. If I'm listening at 80 dB, I'm not using one watt per channel regardless of what amp it is coming from, and I am not aware of any sensory organ on either the Maggies or any other speaker that can identify a difference in taste or feel between one watt from a 10 watt amp or one watt from a 1000 watt amp. IMO if people really hear a difference in the Maggies at high power, it has to be because they are listening loudly enough to cause the Maggies to compress. Certainly possible they compress in a musically enjoyable fashion. I wouldn't know because I don't listen that loud.
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post #196 of 637 Old 09-10-2013, 03:48 PM
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The whole drunk driver aspect of this thread is stupid. Most of the angst you see on audio forums about clipping is not from extreme or foolish use, but worry that their speakers may be damaged in normal use.
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post #197 of 637 Old 09-10-2013, 03:58 PM
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The whole drunk driver aspect of this thread is stupid. Most of the angst you see on audio forums about clipping is not from extreme or foolish use, but worry that their speakers may be damaged in normal use.

most of the thread, as I read it, is an attempt by the forces of truthiness to kick down the idea that clipping is going to kill your speakers.

FWIW, the science is really clear that getting drunk makes things seem quieter (like beer goggles for your ears, kinda)

besides which, since I made every effort to demonstrate that my comment was intended as a sillyish aside, pointing out that it's sillyish seems, um, redundant.

Have another. Turn it up.
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post #198 of 637 Old 09-11-2013, 01:18 AM - Thread Starter
 
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Amplifiers can clip when asked to output either more volts or more current than the power supply can provide. Which limit is reached first depends on the impedance of the loudspeakers.

Please bear with me, because I'm having a little difficulty understanding something. An amplifier delivers let's say 100 watts into 8 ohms at 0.1% THD. At 40% THD it deliveres 150 watts. Is 40% the clipping point?

Because amplifiers can increase in distortion without clipping taking place. So 10% distortion is presumably not at the point where an amp would normally clip, hence my question of overhead. Does the clipping result in up to double the rated power at clean 0.1% distortion, or could it be double the rated power at 10% distortion? I'm not clear on this.
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post #199 of 637 Old 09-11-2013, 03:23 AM
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Absolutely. I have had, on two occasions, at parties, someone in the 'not entirely sober' category, wind the volume up on my music system, which has resulted in a blown driver. Not only does alcohol make people impervious to loud sounds it seems, but also to horrific pre-death distortion. Nowadays, I take steps to ensure this cannot happen but in the good ol' days we had fewer resources at our disposal for controlling maximum SPLs.

handguns just aren't as popular over there, are they? smile.gif

just to be clear, "that's a joke, son"

 

LOL. Unfortunately, no, they are not.  In fact, it is illegal to own a handgun as a private citizen. They were banned several years ago. Made no difference to gun crime - I guess the bad guys didn't read the memo...



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post #200 of 637 Old 09-11-2013, 05:08 AM
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An amplifier delivers let's say 100 watts into 8 ohms at 0.1% THD. At 40% THD it delivers 150 watts. Is 40% the clipping point?

No, 100 watts is probably more than the clipping point.

Good SS amps have THD in the 0.01- 0.05% or even less range, just before clipping. Any good SS amp that is producing 0.1% THD is already clipping.

Here is a graph of power output versus THD for a good but not exceptional amplifier



(There are so-called PA amplifiers and AVRs that will outperform it for THD)

The point where THD starts rocketing for the top of the graph is the clipping point.

Quote:
Because amplifiers can increase in distortion without clipping taking place

You can see that happening between 10 and 500 watts in the graph above. THD is still below 0.05% in this range.
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. So 10% distortion is presumably not at the point where an amp would normally clip,

10% THD usually takes a lot of clipping. It's so much clipping that it would probably be audible to a casual listener.
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post #201 of 637 Old 09-11-2013, 05:14 AM
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This is the key point. Once an amplifier is clipping so badly that it adds enough HF content to damage your tweeters, the music would sound horribly distorted. Who listens like that?

--Ethan

Not to be too flip, but: drunk people.

+1

Got to remember that alcohol is a general anesthetic and it numbs the nerves in the body, including of course the brain.
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Not only ae they less attentive to the sound of the distortion, but alcohol makes things sound quieter so they want to turn it up to get the same sensation they had before that first couple of beers . . .

Exactly. In almost 30 years of online conferencing I've read countless accounts of people who destroyed good stereos under the influence of...
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post #202 of 637 Old 09-11-2013, 06:08 AM - Thread Starter
 
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Originally Posted by arnyk 
10% THD usually takes a lot of clipping. It's so much clipping that it would probably be audible to a casual listener.

Thank you for correcting me! For some reason I assumed clipping would mean a lot more than 0.1% distortion, so I'm very surprised by this. Very interesting! Thanks again for the information.
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post #203 of 637 Old 09-11-2013, 06:11 AM - Thread Starter
 
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Originally Posted by arnyk 
Good SS amps have THD in the 0.01- 0.05% or even less range, just before clipping. Any good SS amp that is producing 0.1% THD is already clipping.

Could you please explain what happens to the average power vs peak power during clipping? I read that the average power is increased to a point where the additional heat cannot be dissipated, but the peak power won't increase.

Is that basically what happens during clipping? At some point the average power just goes up and up and then the tweeter can't cool down enough and eventually burns out?
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post #204 of 637 Old 09-11-2013, 10:30 AM
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Could you please explain what happens to the average power vs peak power during clipping? I read that the average power is increased to a point where the additional heat cannot be dissipated, but the peak power won't increase.

Is that basically what happens during clipping? At some point the average power just goes up and up and then the tweeter can't cool down enough and eventually burns out?

Don't confuse the issue. Average and peak power levels are a function of your speaker sensitivity and listening habits. They are factors to consider when choosing appropriate amplification, simple as that. The amp ideally should never clip for anything you listen to. Fortunately, typical average levels in domestic situations using speakers of typical sensitivity require a mere watt or two. The mainstream mid level 100w AVR has enough power to cover peak output, particularly when bass is of-loaded to subs.

Tweeters overheat because of too much power being applied, regardless if it's coming from a clipped amp or not.

Regarding the power delivered during clipping, visualize music on a scope, or graphically represented as in the above posts (Arny's at #174). The area under the curve, or between the positive and negative deflections from the zero point, represents the power. A heavily clipped signal will have much more relative area under the curve than an unclipped signal. Does this help you understand where the added power from a clipped amp comes from? (Not that you would ever be able to stand to listen to such distortion without diving head long for the volume control...)
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post #205 of 637 Old 09-11-2013, 12:00 PM
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Most of the angst you see on audio forums about clipping is not from extreme or foolish use, but worry that their speakers may be damaged in normal use.

I agree, though listening drunk does dull the senses, as Arny said and I can corroborate. biggrin.gif

--Ethan

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post #206 of 637 Old 09-11-2013, 12:56 PM
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just one more comment. Using a real world amp measurement, we can see that the potential added power above rated output problem comes from amp power, not the harmonics of THD.

I looked at a simaudio moon amp recently reviewed in stereophile. http://www.stereophile.com/content/simaudio-moon-evolution-880m-monoblock-power-amplifier-measurements

The "knee” in the power versus distortion curve is right about 400 watts, as I see it. THD plus noise is right at 0.03 percent, or just about 70 dB below the clean signal. That means the distortion, if I calculated right, contains 0.000038 watts out of the 400 watts the amp is putting out. At one percent distortion, the total measured power is reported as 1050 watts (looking at the chart, I’d have just said “over 1000 watts.”) Anyway, at one percent distortion, the distortion products are 40 dB below the clean signal, so the distortion itself is 0.1 watt out of the total 1050 watts. But total power has more than doubled from where it was when distortion began rising. By the place where the chart is lopped off, at three percent distortion, power looks to me to be up to around 1200 watts, distortion 30 dB down, making up 0.9 watt out of the 1200.

Three percent THD might not be noticeable and the SPL difference between 1050 and 1200 watts may be minimal, but that extra 150 not-yet-totally-distorted-sounding watts might be plenty to take a speaker’s tweeter from hard-pressed to dead. Unlikely the extra 0.9 watt from distortion products is what would push it over the edge, though.
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post #207 of 637 Old 09-12-2013, 10:52 AM - Thread Starter
 
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Don't confuse the issue. Average and peak power levels are a function of your speaker sensitivity and listening habits. They are factors to consider when choosing appropriate amplification, simple as that. The amp ideally should never clip for anything you listen to.

The reason I asked about average power and peak power during clipping and why I wanted clarification on this is because of this article I read recently :

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

Apparently this member also posts on AVS. Apparently when an amplifier clips the peak power doesn't go up but the average power does and it is the average that kills the tweeter over time. Do you agree with that?
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post #208 of 637 Old 09-12-2013, 10:59 AM
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Originally Posted by JHAz 
Don't confuse the issue. Average and peak power levels are a function of your speaker sensitivity and listening habits. They are factors to consider when choosing appropriate amplification, simple as that. The amp ideally should never clip for anything you listen to.

The reason I asked about average power and peak power during clipping and why I wanted clarification on this is because of this article I read recently :

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

Apparently this member also posts on AVS. Apparently when an amplifier clips the peak power doesn't go up but the average power does and it is the average that kills the tweeter over time. Do you agree with that?

 

As Bill says in the article - the thing that damages the speaker is giving it too much power - more power than it can handle. It doesn't matter what that power 'consists of' - the speaker has no way to know what kind of signal, clean or distorted, clipped or unclipped it is being fed - it's just 'signal' - but if the speaker cannot handle the power then it will fail.

 

Do you agree now that clipping cannot damage speakers?  (Remember the guitar player analogy).



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post #209 of 637 Old 09-12-2013, 11:27 AM
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As Bill says in the article - the thing that damages the speaker is giving it too much power - more power than it can handle. It doesn't matter what that power 'consists of' - the speaker has no way to know what kind of signal, clean or distorted, clipped or unclipped it is being fed - it's just 'signal' - but if the speaker cannot handle the power then it will fail.

Do you agree now that clipping cannot damage speakers?  (Remember the guitar player analogy).

+1. A lot depends on what a person means by "clipped." Certainly at 1% distortion the waveform is not hugely (to most eyes, perhaps not significantly) affected.

For grins I Googled the THD of a square wave. It appears that a square wave "contains" the fundamental plus 45% total harmonic distortion. Pretty sure nobody's operating at that level of distortion through non musical instrument amplifiers.
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post #210 of 637 Old 09-12-2013, 07:09 PM
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Good SS amps have THD in the 0.01- 0.05% or even less range, just before clipping. Any good SS amp that is producing 0.1% THD is already clipping.

Could you please explain what happens to the average power vs peak power during clipping?

Once clipping commences, the peak power cannot increase. But the average power can and does.

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I read that the average power is increased to a point where the additional heat cannot be dissipated, but the peak power won't increase.

That is true,
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Is that basically what happens during clipping? At some point the average power just goes up and up and then the tweeter can't cool down enough and eventually burns out?

Yes. Hence the comment that its excess average power that burns out speakers.
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