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Clipping or Too Much Power?

Pandovski said:
So it comes down to either own fleawatt amp or pair of monoblocks. Anything in-between will kill tweeters when a Crescendo explodes in a tune.
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I'd say use an amplifier that produces enough power for your needs, or even beyond, and then learn to listen for audible signs of speaker distress. If you use a smaller amp than you'd like, listen for frequency balance changes and know when to turn it down, or be content with what the amp can do.

I have amps ranging from 7wpc to 200wpc @ 8 ohms, and they perform fine within their design parameters. I've blown a few car audio speakers, but never a home audio speaker.
 
i have never had any problems regarding this,i never listen to loud music as i dont want to burn out my gear and upset the the old guy that lives next door lol ,never above loud speaking ,which on the meters say about 4-6watts and its very loud to me ,cant see how listening to it any louder is nice,maybe im just a nana lol

mike
 
new said:
i have never had any problems regarding this,i never listen to loud music as i dont want to burn out my gear and upset the the old guy that lives next door lol ,never above loud speaking ,which on the meters say about 4-6watts and its very loud to me ,cant see how listening to it any louder is nice,maybe im just a nana lol

mike
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oh so how loud in db would clipping happen ?must be very loud,

sorry if i sound abit silly with asking things like this ,but i just dont know:no:

mike
 
Pandovski said:
So it comes down to either own fleawatt amp or pair of monoblocks. Anything in-between will kill tweeters when a Crescendo explodes in a tune.
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Read the JBL tech letter, you'll be glad you did.

Clipping does not blow tweeters, they don't give a **** about the shape of the signal waveform.

High frequency harmonics generated by amplifiers that don't behave well when clipped blow tweeters by sending them TOO MUCH POWER in their operating bandwidth.

Some amplifiers when clipped hard can output HF harmonics at levels well above the amplifier's rated output. Some of the more poorly designed amplifiers will even oscillate when clipped hard.

I still think an amp has to be somewhat powerful to blow a tweeter. It isn't going to happen with a 5 wpc amp no matter how hard it's clipping.
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To the degree that it has to be able to pass enough voltage/current at frequency to exceed the tweeter's thermal limits in some fashion, this is true. But, only in that context.

Still confused? Change the word tweeter to fuse. A fuse opens for exactly the same reason a tweeter coil burns out.
 
davidro said:
My understanding from the posts of Ken Kantor and other proponents is that it's too much power that blows speakers, not clipping. I still see a lot of usually knowledgeable members insist on the latter.

Which is correct? Let's settle the issue once and for all.
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Hey Davidro, Clipping was explained to me on a piece of paper, three lines were drawn, a centre line (0 volts) a top line (+X Volts) (where x equals number of volts) a bottom line (-X Volts). if X equals 15 and you have turned the volume up to much, clipping occurs because you ain't gonna get a 16 volt swing. I am not real tech minded with terms so please be patient with me. The amp tries to output a fluctuating voltage which moves the voice coil in and out of its gap between magnets, this movement cools the coil. When clipping occurs a DC current is received by the coil, now the coil cannot move back and forth, it will stop at either one end of its travel or the other depending on polarity. (You can try this on a conventional speaker with a 1.5v battery). Either way the voice coil is now overheating. If clipping is bad enough, the resin insulating the wire in the voice coil will melt and start to bubble, decreasing the gap between the magnets and the coil until it seizes or at least scratches. High power amps wont clip so soon but when they do they do a better job of it. (Worse)

The "not clipping" but overdriving way, the voice coil can move out of the gap, distorting the shape of it and not being a circle any more. Can even through the cone out of the basket, start a fire, both are destructive.
 
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When clipping occurs a DC current is received by the coil.....................
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Tweeters filtered by one or more capacitors in series do not receive DC, ever. They are free to receive harmonics in any quantity.

Transformer coupled amplifiers cannot output DC, ever. They can output harmonics up to the limits of the transformer.
 
89grand said:
No, that's a myth. If an amplifier has not failed, it will not send DC no matter how much it's being clipped.
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I think clipping ressemble a DC signal, wereas the top of the sine wave is

flat, constant energy that keeps the voice coil stuck in forward ( or reverse )

extension, rapidly heating up the thin wire of the vc and then ..pouf !

It's not DC coming out of the ps.

Me thinks !
 
bowtie427ss said:
Tweeters filtered by one or more capacitors in series do not receive DC, ever. They are free to receive harmonics in any quantity.

Transformer coupled amplifiers cannot output DC, ever. They can output harmonics up to the limits of the transformer.
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Then what fried my HF driver, and tweeters aren't the only drivers with voice coils
 
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A 1 kHz sine wave that is turned into a square wave by clipping has no frequency component below 1 kHz. it has lots of components at the odd harmonics - 3 kHz, 5 kHz, etc. - but no dc component.
 
bowtie427ss said:
The same thing that blows a fuse, ultimately.

In a typical SS amplifier clipping at a given frequency generates harmonics at usually higher frequencies than where the "clip" occurred.

The JBL tech letter explains it pretty well in semi-layman's terms.

Here it is again: http://www.jblpro.com/BackOffice/ProductAttachments/lowpower.pdf
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The guy that explained this to me would be very well known at JBL. He's bought hundreds if not thousands of drivers from JBL. You think I'm going to drop what he told me to listen to someone who reads it in a PDF?

I stand my ground. :smoke:
 
Working at Radio Shack in the early 80's was an enlightening experience.

I remember car guys buying car speakers rated to handle lots of watts and equalizer/booster amps rated at 20 wpc. Invariably, a few days later they would come in with a blown speaker. Why? Obviously, the speaker was rated to handle more watts than those little boxes could put out. Ya think their arranging the eq sliders into a smiley face configuration and then blasting the hell outta their system could have had something to do with it?

Likewise, we had the little proto-geeks that would tell us about how they connected a little 3 " transistor radio speaker with their dad's big-ass STA-2000 (or some such) and watched it throw it's cone out of the frame or go out in a brief puff of smoke.

So, I firmly believe that given enough determination and/or stupidity, either can result in a speakers demise.
 
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kahlfin1k said:
When you pass too much current through a wire or coil (voice coil) it burns.
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An open voice coil wire is one driver failure scenario. I've blown (by accident and for fun) many speakers over the years. Sometimes the failure is the adhesive that attaches the voice coil to the cone. It heats up, softens, and allows the voice coil to misalign and jam into the magnet assembly. You know this happened when you push of the woofer and it doesn't move back and forth like normal. I think that scenario should be categorized as failure from too much power, either clipped or not clipped.

Good topic, Ken K's writings definitely changed my mind on the clipping vs too much power issue. I was used to be in the clipping school, but know think its ultimately too much power either clipped or not.
 
rshep said:
An open voice coil wire is one driver failure scenario. I've blown (by accident and for fun) many speakers over the years. Sometimes the failure is the adhesive that attaches the voice coil to the cone. It heats up, softens, and allows the voice coil to misalign and jam into the magnet assembly. You know this happened when you push of the woofer and it doesn't move back and forth like normal. I think that scenario should be categorized as failure from too much power, either clipped or not clipped.

Good topic, Ken K's writings definitely changed my mind on the clipping vs too much power issue. I was used to be in the clipping school, but know think its ultimately too much power either clipped or not.
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Note, at least 2 types of overpowering, thermal and mechanical.

Another interesting failure that can occur happens to woofers used in horns with high compression ratios. The woofer can fail by "popping" or bursting the cone. BFM drives this point home well with some of his earlier Tuba horn subs. In those particular loading scenarios it is possible to break woofers without clipping or thermally overpowering them.

poppedcone.jpg
 
"Originally Posted by kahlfin1k View Post
If a distorted signal fried speakers every guitar amp ever would have blown speakers."

Clipping is distortion, but not all distortion is clipping. When the output waveform is different than the input waveform it's distorted. Example: Input waveform is a sine wave, output waveform is a sawtooth wave. An amplifier should only amplify the input not change it. A clipped output waveform has chopped tops and bottoms, so is different than the input, so is distortion.
 
The JBL paper posted pretty much explains it. For those who say clipping does not send lower frequency information to their tweeters they are incorrect.
What has not been said is how the amplifier clips. If an amplifier clips cleanly it will recover as soon as the peak passes. In a poorly designed amplifier all kinds of strange things happen. Some designs generate high frequency spikes or worse yet 'latch' and continue to dump the DC rail voltage into the speaker. This was common on many amp designs in the 70s and lower powered integrated and receivers may also have these issues. These amplifiers will eat woofers when overdriven.

Thanks,
Ron-C
 
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