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If you send your sub back for warranty because it burned out, the manufacurer can tell from the burn pattern on the voicecoil whether it had too much power or clipping.

Speaker Failure Analysis

1. Black discolouration in the middle or all over the voice coil
This is the most common damage seen and indicates that a well centred coil was driven with too much audio power for too long. The resistance of the burnt coil is often half or less the nominal value due to internal shorting.

2. Black discolouration at one end of the voice coil.
This is also a common sight and indicates either the voice coil was not centred during manufacture OR that the damage was caused by DC current rather than audio frequency current. A large DC current will displace the voice coil to one or other extreme. A faulty amplifier is automatically suspected.

I'm going to call "[email protected]" on the clipping analysis. Power, Yes, but clipping?! I guess they have to make money too, right? SMH
 

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Burned out speakers = too much power that produces enough heat to damage your driver
Burned out speakers = clipping so that it produces enough heat to damage your driver

Lite clipping won't damage anything if your driver can withstand the heat.

Kelvin
As I stated before, direct me to the empirical data. Been around this hobby for over 2 decades and have never seen photos or examples of this thermal degradation. This is something that would have been clearly replicated by the infinite amount of hobbyists who are always looking to push the envelope or push their equipment to the max.

What the poster above states is the factual truth and what should be conveyed when someone brings up this discussion.
I think you are both in agreement. I'm taking subwoofery's statement as you can smoke a coil one of two ways:

1) Too much clean power with an oversized amplifier rated well beyond your speaker's continuous RMS rating

2) With too much clipped power from an amp that is matched to your speaker's continuous RMS rating.


Of course, the validity of the amp's and speaker's rated specs come into play, but if you have a perfectly matched amp RMS power and speaker RMS power (continuous RMS specs on both counts), you can still smoke the coil with heavy-duty clipping as the amp is putting out a good deal more RMS power than it's rated for (equals more heat at the coil). All those flat clipped waveforms slamming into the +/- rails directly translate to a higher duty-cycle of the waveform - and that means more RMS power...

I'm going to call "[email protected]" on the clipping analysis. Power, Yes, but clipping?! I guess they have to make money too, right? SMH
Agreed 100% with that. All that article really tells you is that certain motor designs will exhibit characteristic burn patterns based off how much of the coil is in the gap, or how the coil might look if the speaker contained a manufacturing defect. There's just no way for the manufacturer (or anyone that is not intimately familiar with the system as a whole) to accurately determine "clean overpowered failure" vs "clipped overpowered failure".

Regardless - Both scenarios will exceed the coil's/motor's RMS heat sinking abilities in a similar fashion - and both would qualify as "Overpowering the Speaker" IMNSHO.

:cool:
 

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6 of one; half a dozen of another :)



Wait - Exactly how old are you :p
lol Just turned 30 :surprised:

I can say whatever I want... This is the internet afterall :D

Kelvin
 

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Part of what I took from this is that a smaller amplifier delivers a lot more distortion when pushed into clipping as well. So there's two problems in the picture, 1) sine wave like input and 2) more work/less cooling due to the higher distortion and noise floor.

Both of those would seem to allow more power to the coil without much of a break. Doesn't that mean it's easier to burn up a coil when pushing an amp too far? A speaker coil was designed to play with music, which is dynamic and not constant.
 

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Maybe a lot of assumptions are being thrown around? I thought of this article in a sense of somebody using gain incorrectly. Mostly because almost every person I've ever helped points out right away that their sub sounds best when they turn the gain all the way up.

Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe? But I failed to mention my assumption of a poorly set gain.

I agree that if gains are set correctly I don't understand why an amplifier would hurt any speaker that's setup appropriately. But I usually only see people turn the gain up too much when using smaller amps.
 

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Distortion doesn't increase power. The size of the amplifier has nothing to do with its clipping characteristics.
depends on how you qualify "distortion" clipping is still distortion and it certainly does add power.
 

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If you send your sub back for warranty because it burned out, the manufacurer can tell from the burn pattern on the voicecoil whether it had too much power or clipping.

Speaker Failure Analysis

1. Black discolouration in the middle or all over the voice coil
This is the most common damage seen and indicates that a well centred coil was driven with too much audio power for too long. The resistance of the burnt coil is often half or less the nominal value due to internal shorting.

2. Black discolouration at one end of the voice coil.
This is also a common sight and indicates either the voice coil was not centred during manufacture OR that the damage was caused by DC current rather than audio frequency current. A large DC current will displace the voice coil to one or other extreme. A faulty amplifier is automatically suspected.

I'm not sure what you're implying here, but DC offset has absolutely nothing to do with clipping.
 

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Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe?
Coils don't breathe! :) They also don't sweat, piss, shit, or anything else.

Coils also don't know what distortion is. They don't have access to the original (undistorted) waveform, so it is impossible for a coil to be affected by distortion. Distortion only affects human beings, because as humans we have the unique ability to have expectations about what something should sound like. So we're pretty damned good at identifying distortion. [actually, we're pretty bad at it, but sssshhhhhhhh!]

The only thing that coils "know" is how much energy they're being driven with, how much energy they were driven with a few seconds/minutes ago, what the frequency content of that energy is, and how hot or cold the local environment is. Those are the things that will determine whether your speaker will live or die.
 

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I'm not sure what you're implying here, but DC offset has absolutely nothing to do with clipping.
I didn't write those notes. I copied them from the link that I included to illustrate my statement that the manufactures can tell from the burn patterns on the VC what kind of abuse that it encountered. I am learning and appreciate anybody's input or clarification.

I remember reading on multiple occasions over the years about the effects of clipping and the damage it causes, but the article I referenced actually refuted those claims.

Since you mentioned it, doesn't DC offset affect clipping? In a simple amplifier, don't you want to bias a transistor at the midpoint of its linear range so that it can handle the positve and negative halves of the signal equally? If the bias is offset too little or too much, the transistor will cut off on the low end or saturate on the top end.
 

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I didn't write those notes. I copied them from the link that I included to illustrate my statement that the manufactures can tell from the burn patterns on the VC what kind of abuse that it encountered. I am learning and appreciate anybody's input or clarification.

I remember reading on multiple occasions over the years about the effects of clipping and the damage it causes, but the article I referenced actually refuted those claims.

Since you mentioned it, doesn't DC offset affect clipping? In a simple amplifier, don't you want to bias a transistor at the midpoint of its linear range so that it can handle the positve and negative halves of the signal equally? If the bias is offset too little or too much, the transistor will cut off on the low end or saturate on the top end.
that is why most amplifiers are push-pull. you have 1 device baised positive and 1 baised negative. only 1 device is ever "on" at a time.

no matter what class you use, there the DC bias is NEVER on the output of the amplifier. more than a few mV of bias voltage at the output is rare.
 

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that is why most amplifiers are push-pull. you have 1 device baised positive and 1 baised negative. only 1 device is ever "on" at a time.

no matter what class you use, there the DC bias is NEVER on the output of the amplifier. more than a few mV of bias voltage at the output is rare.
Oh, I see what you are getting at. That is if the DC bias is actually presented to the speaker. No, it shouldn't be directly flowing through the speaker. Just between the base and emitter of the transistor. However, it will indirectly affect the speaker output if it isn't adjusted properly.
 

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Maybe a lot of assumptions are being thrown around? I thought of this article in a sense of somebody using gain incorrectly. Mostly because almost every person I've ever helped points out right away that their sub sounds best when they turn the gain all the way up.

Doesn't a coil need to shed heat? If it's busy playing distortion or getting stressed out due to clipping, when will it get a chance to breathe? But I failed to mention my assumption of a poorly set gain.

I agree that if gains are set correctly I don't understand why an amplifier would hurt any speaker that's setup appropriately. But I usually only see people turn the gain up too much when using smaller amps.
How does a speaker, any speaker know the difference between a clean signal and a distorted one? If the speaker is still oscillating then it's shedding heat regardless of the signal it's getting.

depends on how you qualify "distortion" clipping is still distortion and it certainly does add power.
I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.
 

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I didn't write those notes. I copied them from the link that I included to illustrate my statement that the manufactures can tell from the burn patterns on the VC what kind of abuse that it encountered. I am learning and appreciate anybody's input or clarification.
That's fine. I'm just trying to point out that when the second note talks about DC offset, it means that there was coil offset that resulted from a defective amplifier with a nonzero DC bias. This doesn't have anything to do with clipping... your post looked like you were trying to attribute those notes to clipping, that's why I responded.

I remember reading on multiple occasions over the years about the effects of clipping and the damage it causes, but the article I referenced actually refuted those claims.

Since you mentioned it, doesn't DC offset affect clipping? In a simple amplifier, don't you want to bias a transistor at the midpoint of its linear range so that it can handle the positve and negative halves of the signal equally? If the bias is offset too little or too much, the transistor will cut off on the low end or saturate on the top end.
Yup! DC of any sort will produce asymmetric clipping. But that would be the least of your problems if you had that much offset.

Oh, I see what you are getting at. That is if the DC bias is actually presented to the speaker. No, it shouldn't be directly flowing through the speaker. Just between the base and emitter of the transistor. However, it will indirectly affect the speaker output if it isn't adjusted properly.
Don't confuse offset with bias. Bias can be adjusted to accommodate a particular design, but offset should always be as close to zero as possible. Some designs are intentionally overbiased into class A/B (out of laziness IMO ;)), but they should still produce an offset on the order of a few millivolts.
 

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I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.
This is a good point. It all gets down to semantics.

If you're comparing a signal that maxes out at 35v but isn't clipping vs. one that maxes out at 35v but IS clipping, the clipped signal will have more energy.

If you're comparing a signal that maxes out at 50v without clipping, but shove that SAME signal at the same amplitude level into an amp with 35v rails, the clipped signal will have less energy.

Clipping is a form of compression. Literally. If you buy a compressor, and set it to a hard knee with really fast attack, you're compressing the signal by clipping it. ;) So, in the real world, if you clip your signal, you're going to be giving the speaker LESS energy overall than you would if you had an amp with no limitations.

The old motto was "clipping blows speakers". Maybe the new motto should be that clipping saves speakers. :D

[the caveat here is when tweeters are on passive crossovers... then it's a different story]
 

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That's fine. I'm just trying to point out that when the second note talks about DC offset, it means that there was coil offset that resulted from a defective amplifier with a nonzero DC bias. This doesn't have anything to do with clipping... your post looked like you were trying to attribute those notes to clipping, that's why I responded.



Yup! DC of any sort will produce asymmetric clipping. But that would be the least of your problems if you had that much offset.



Don't confuse offset with bias. Bias can be adjusted to accommodate a particular design, but offset should always be as close to zero as possible. Some designs are intentionally overbiased into class A/B (out of laziness IMO ;)), but they should still produce an offset on the order of a few millivolts.
Thanks for clarifying. I need to refresh my knowledge. I think my memory isn't what it use to be.
 

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I see what you're saying, but I think of distortion as just that. I don't lump clipping into that because one is signal and the other is power. Related but a distorted signal is not necessarily clipped. Agreed that clipping adds power.
I call anything distortion that"distorts"the signal. If the output doesn't follow the input, then it is distorted


Sent from my motorola electrify using digital farts
 

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First time reading this and damn near got a headache trying to keep up with it. Guess I'm destined to damage my drivers since I'm upgrading to more power for headroom.... I give up. :(
 
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