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#1

It's a multi layered issue.

As clipping increases, the voltage sent to the driver will approach the peak to peak voltage of the original sine wave. 

Peak voltage in the wave is 1.41 times as much as the RMS voltage of a clean sine. And due to the apparent power increase as a function of the square of the voltage, it results in a theoretical ~200% power delivery to the driver

Combine that with the changes in inductance since this is now a DC signal instead of A/C - impedance rise goes down, resulting in again, increased power delivery

And the final nail in the coffin is that because the peak to peak voltage isn't actually increased, your electromagnetic force in the driver isn't increased, you you won't see much more cone movement to provide the increase in cooling needed to dissipate all this extra heat

Edited by SnowDrifter

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I'm just here to soak in the knowledge.

 


That being said a lot of people's definition of "music" is a clipped 30 hz sine wave with some 80 IQ knuckle head grunting about committing crimes and his genitals.

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16 hours ago, SnowDrifter said:

#1

It's a multi layered issue.

As clipping increases, the voltage sent to the driver will approach the peak to peak voltage of the original sine wave. 

Peak voltage in the wave is 1.41 times as much as the RMS voltage of a clean sine. And due to the apparent power increase as a function of the square of the voltage, it results in a theoretical ~200% power delivery to the driver

Combine that with the changes in inductance since this is now a DC signal instead of A/C - impedance rise goes down, resulting in again, increased power delivery

And the final nail in the coffin is that because the peak to peak voltage isn't actually increased, your electromagnetic force in the driver isn't increased, you you won't see much more cone movement to provide the increase in cooling needed to dissipate all this extra heat

That was a well thought out answer SD.  Let me impart a fact that may help you to fine tune your answer - amplifiers do not output DC when they clip.

I'll give you a hint - you do actually answer the question correctly within your explanation, but you also kind of ride the fence.  The correct answer is one or the other.


Tony Candela - SMD Sales & Marketing
Email me at [email protected] to learn about becoming an SMD Partner!

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15 hours ago, Broke_Audio_Addict said:

I'm just here to soak in the knowledge.

 

Hey, at least have a guess.  No risk, no reward!


Tony Candela - SMD Sales & Marketing
Email me at [email protected] to learn about becoming an SMD Partner!

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On 2017-5-25 at 8:16 AM, snafu said:

Here's another one.  See if you can choose the correct answer.

Clipping your amplifier will damage your speakers.  Yes, this is true, but why?

1 - Clipping shears off the top and bottom of the waveform.  The resultant AC signal to your speakers is really more like DC.  This is hazardous to speakers and the voice coils can be damaged as a result.

2 - Clipping can damage your speakers when the result of clipping is overpowering.

Go.

#1 is irrelevant because it really depends on the amplitude of clipping, usually limited by the amplifier.

#2, true - any speaker that is being powered properly or with headroom can easily be clipped into dangerous power levels mechanically & electrically.

 

 

 

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On 5/25/2017 at 2:16 PM, snafu said:

Here's another one.  See if you can choose the correct answer.

Clipping your amplifier will damage your speakers.  Yes, this is true, but why?

1 - Clipping shears off the top and bottom of the waveform.  The resultant AC signal to your speakers is really more like DC.  This is hazardous to speakers and the voice coils can be damaged as a result.

2 - Clipping can damage your speakers when the result of clipping is overpowering.

Go.

Can't it be both? 

1. Clipping cause a speaker to become stopped at a certain distance from resting rather than a fluid in and out motion. Like somebody else mentioned, there is no movement in the moment of clipping so the voice coil doesn't benefit from moving to help cool it down. Can lead to a thermal failure.

2. Clipping from overpowering can lead to both thermal and mechanical failure. Thermal - If the power being sent to the speaker is too much for the voice coil to handle thermally, poof. There goes smoke. Mechanically - Even if the speaker can handle the heat caused by extra power, this extra power can cause the speaker to exert more than it was intended to mechanically, causing the coil to jump the gap and break. 

Just a guess, you seem like you want to teach and I always love learning new things ?

 


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9 hours ago, snafu said:

That was a well thought out answer SD.  Let me impart a fact that may help you to fine tune your answer - amplifiers do not output DC when they clip.

I'll give you a hint - you do actually answer the question correctly within your explanation, but you also kind of ride the fence.  The correct answer is one or the other.

#1:D

To clarify, yes it puts out AC, even if a square wave. However looking at the clipped peaks where it will, for a small moment, behave as DC

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On 5/25/2017 at 6:22 PM, SnowDrifter said:

Peak voltage in the wave is 1.41 times as much as the RMS voltage of a clean sine. And due to the apparent power increase as a function of the square of the voltage, it results in a theoretical ~200% power delivery to the driver

#2 is the correct answer and your explanation here is entirely accurate.  [Vrms / .707 = Ppeak . . . or Vrms x 1.414 = Ppeak . . . same difference.  Who can explain why that is?]

Loudspeakers cannot discern a clipped signal from a non-clipped signal, a distorted signal from a non-distorted signal, etc.

BITD, we were under the belief that underpowering a speaker would lead to damaging it.  Think about that for a second.  Our volume control has a range from 1 to 10.  With it set to 10, our amplifier delivers 100 Watts to our 100 Watt speaker.  Therefore, any setting below 10 would be underpowering the speaker.  That makes no sense and we couldn't have been more wrong.  Mr. Customer - in order not to damage your speakers, please keep the volume control at 10 at all times.  At the drive thru, 10.  At the bank window, 10.  On the phone, 10.  Talking to an officer after being pulled over, 10.  Car parked in the garage at night, 10.  Obviously, what we were trying to achieve was not setting the customer up with an amplifier that was too small for a given speaker.  Our fear was that amplifier, when driven into clipping, would damage the speaker as we believed clipping was the cause of speaker damage.  I learned the truth only after I joined Rockford in 2002.

Let me explain.  Let's say that we have a 25 Watt RMS power amplifier and a 100 Watt RMS power amplifier that are identical in every way (with exception of power rating) and our speaker is rated to handle 100 Watts RMS.

First, we power our 100 Watt speaker with the 25 Watt amplifier.  At 25 Watts (clean), the 100 Watt speaker would receive . . . well, 25 Watts.  [How is that 25 Watts different from 25 Watts produced by a 100 Watt power amplifier?  To the speaker, it isn't.]  Now, if we attempt to drive the speaker a little harder with our 25 watt amplifier, we run into the limitations of the amplifier.  Yet, it can still make up to double its 25 Watt rating with a fully clipped signal.  So, now our 100 Watt speaker sees up to 50 Watts of power with the 25 Watt amplifier driven into hard clipping.  While it may sound really offensive, the speaker will survive.

Now, we power our 100 Watt speaker with the 100 Watt amplifier.  All is fine until we drive our 100 Watt amplifier into severe clipping, where it can produce up to 200 Watts - double our speaker's power rating.  As our 100 Watt speaker is not rated to handle 200 Watts it expires as the voice coil is unable to dissipate the additional heat generated by the additional 100 Watts, which causes it to be . . . well, barbecued.

So really, the cause of blown speakers is that we do not understand what I outlined earlier in this thread - that Peak and RMS speaker ratings are the very same thing, just stated differently.  [27 feet vs. 9 yards . . . 4 quarts vs 1 gallon . . . 1,320 feet vs 1/4 mile . . . ]  Because we don't understand that, the result of our scientific findings when we do blow speakers is that clipping damages speakers.  Since our foundation wasn't solid, the conclusion we drew was incorrect.

Don't believe me?  Refer to #5 in the OP and get to work.

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Tony Candela - SMD Sales & Marketing
Email me at [email protected] to learn about becoming an SMD Partner!

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