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can high frequencies damage a subwoofer?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=95939
Printed Date: May 27, 2022 at 10:38 AM


Topic: can high frequencies damage a subwoofer?

Posted By: jmelton86
Subject: can high frequencies damage a subwoofer?
Date Posted: July 26, 2007 at 6:32 PM

Can high frequencies damage a subwoofer? Well, can they?

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2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
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Replies:

Posted By: installerman23
Date Posted: July 26, 2007 at 6:33 PM
Yes.

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installing, one day at a time..




Posted By: jmelton86
Date Posted: July 26, 2007 at 6:47 PM
Can someone explain? I don't understand how. I know a woofer won't reproduce high frequencies as efficiently as a tweeter, but I don't see how they can damage a woofer.

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2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001




Posted By: Alpine Guy
Date Posted: July 26, 2007 at 7:34 PM
They can't damage a sub.

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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.




Posted By: DYohn
Date Posted: July 26, 2007 at 8:45 PM

Alpine guy is right, a speaker is a speaker.  It's not frequency that can damage one, it's power.

There are many reasons why you want to block higher frequencies from reaching your sub, but damaging the speaker is not one of them.



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Posted By: Steven Kephart
Date Posted: July 26, 2007 at 10:09 PM

Here's proof that high frequencies can't harm a subwoofer:

https://www.realmofexcursion.com/videos/Adire/brahma12.13.wmv

The only speaker playing in that video is the sub.





Posted By: sparky3489
Date Posted: July 26, 2007 at 11:36 PM

I have to say I disagree as high frequency through a sub still puts the same power to it, but the cone travels less resulting in the coils to get hotter quicker which can cause warping. The sub is destroyed in a short amount of time, however this is ONLY if nothing but high frequency is pushed. The less high frequency you push to a sub the better.

This is why they have frequency responses.





Posted By: DYohn
Date Posted: July 26, 2007 at 11:54 PM
sparky3489 wrote:

I have to say I disagree as high frequency through a sub still puts the same power to it, but the cone travels less resulting in the coils to get hotter quicker which can cause warping. The sub is destroyed in a short amount of time, however this is ONLY if nothing but high frequency is pushed. The less high frequency you push to a sub the better.

This is why they have frequency responses.


This is absolutely incorrect.  Whoever told you this did not know what they were talking about.



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Posted By: Steven Kephart
Date Posted: July 27, 2007 at 1:45 AM
sparky3489 wrote:

I have to say I disagree as high frequency through a sub still puts the same power to it, but the cone travels less resulting in the coils to get hotter quicker which can cause warping. The sub is destroyed in a short amount of time, however this is ONLY if nothing but high frequency is pushed. The less high frequency you push to a sub the better.

This is why they have frequency responses.


Subwoofers have a very large coil of wire sitting around a large piece of metal which results in very high inductance.  Because of this, they have a built-in low pass filter.  This inductance combines with the DC resistance of the sub resulting in an increasing impedance with frequency.  This means that less power will be drawn from the amplifier at higher frequencies.





Posted By: jmelton86
Date Posted: July 27, 2007 at 3:03 AM
Also, i've never seen (higher end) speaker companies bragging about advanced cooling features on their tweeters. I do see your point on how since the sub doesn't move so much with higher frequencies it doesn't cool itsself, but it's not needed because of the higher impedance.

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2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001




Posted By: mjwood0
Date Posted: July 27, 2007 at 4:57 AM
sparky3489 wrote:

I have to say I disagree as high frequency through a sub still puts the same power to it, but the cone travels less resulting in the coils to get hotter quicker which can cause warping.


I think this is a common belief due to the misunderstanding that power doesn't get pushed from an amp, but pulled from it. Current will only flow if there is a difference in potential -- electricity 101.




Posted By: willdkartunes
Date Posted: July 27, 2007 at 10:41 PM
DYohn] wrote:

Alpine guy is right, a speaker is a speaker.  It's not frequency that can damage one, it's power.

There are many reasons why you want to block higher frequencies from reaching your sub, but damaging the speaker is not one of them.


Not sure if this one is entirely correct... It is possible to damage a sub depending on frequency. If you have a sub in a ported enclosure and play a frequency lower than port tuning frequency, it is possible to damage the sub. Of course you guys were talking about high frequencies, but I just thought I would throw that in there...  posted_image



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Posted By: sparky3489
Date Posted: July 28, 2007 at 12:25 PM

WOW!!

I'm absolutely amazed at some of these answers. Such a pity.

Esecially, "I think this is a common belief due to the misunderstanding that power doesn't get pushed from an amp, but pulled from it. " 

So if I kink a garden hose, I'm pulling water pressure and not forcing more pressure?!?!? wth?!?!

GET A CLUE PEOPLE!





Posted By: DYohn
Date Posted: July 28, 2007 at 12:35 PM
willdkartunes wrote:

DYohn] wrote:

Alpine guy is right, a speaker is a speaker.  It's not frequency that can damage one, it's power.

There are many reasons why you want to block higher frequencies from reaching your sub, but damaging the speaker is not one of them.


Not sure if this one is entirely correct... It is possible to damage a sub depending on frequency. If you have a sub in a ported enclosure and play a frequency lower than port tuning frequency, it is possible to damage the sub. Of course you guys were talking about high frequencies, but I just thought I would throw that in there...  posted_image


You are right that a signal below the port tuning frequency can damage a sub since it is no longer loaded by the enclosure at those frequencies, but it is NOT the frequency of the signal that can drive the speaker to its mechanical limits, it is the power of the signal.  It is power that damages speakers, not frequency.

Loudspeakers do not care what frequency you send them.  They will reproduce it, no matter if the speaker in question is a woofer or a tweeter or any variation.  The motor system will respond to the frequency presented, and while they do so with different efficiencies depending on their physical construction (which is why we use different types of speakers) they all respond in the same basic ways.  Don't forget there are some very high-quality full-range drivers that can reproduce the full audio spectrum.  There is really  no fundamental difference between any two dynamic drivers: they all use a coil of wire and a magnet.

Frequency will not damage a speaker all by itself.  It is the power driving the signal that is the issue.



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Posted By: DYohn
Date Posted: July 28, 2007 at 12:46 PM

re: pushing or pulling.  It's both.  Amplifiers produce voltage.  Voltage produces current flow through a resistance.  Power is the product of these effects.  So, the amplifier provides the motive force (the "push") for the current flow.  The resistance (impedance) of the speaker determines how much current will flow through it from the available voltage force (the "pull.") 

So, if we want to be very imprecise and non-scientific about it, the amplifier "pushes" and the loudspeakers "pull" and neither can work without the other. 



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Posted By: KarTuneMan
Date Posted: July 29, 2007 at 10:41 PM
I like this stuff..........posted_image

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Posted By: audiocableguy
Date Posted: July 30, 2007 at 11:46 AM
I posed the following info to JL Tech Support:

I came across this posting and believe it to be absolutely a false statement. Wondering if you might be able to shed some light on this subject. Thank You.

"I’d have to disagree with this statement purely on the basis that whoever said it is referring to cone motion as being directly in relation to thermal rating, with the exception of a very few drivers, motion is minimally involved in cooling. Keep in mind, a tweeters movement has very little to do with cooling of tit’s voice coil. Also, dependant upon how/ why those frequencies are being applied to the woofer can make a huge difference as to the drivers response"




Posted By: DYohn
Date Posted: July 30, 2007 at 12:02 PM
audiocableguy, what about that statement do you think is false?

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Posted By: haemphyst
Date Posted: July 30, 2007 at 3:23 PM
audiocableguy, I think you might have either a: not given the JL Tech all of the information necessary for him to ACCURATELY answer your question, or b: misunderstood what the question was in the first place, or c: a little of both. Just reading your post, I cannot tell what you posed to the tech as the actual question, or what his actual response to your query was.

The lack of motion is really the same as holding the cone, right? So, with all of the information already provided, it can be PROVEN, BEYOND A SHADOW OF A DOUBT, that high frequencies CANNOT damage a woofer. Period. Those facts are:

1: N0 (that's "Eta null") is the amount of power INPUT to a woofer that is actually converted to AUDIO. Typically .4% or so, and I have never seen higher than .7% myself. (Dan Wiggins mentioned at some time or another N0 of as high as 1%, but I've never seen it, personally) If we have, for example, a woofer with an N0 of .5%, and a power rating of 1000 watts, the math is applied like this 1000*.5%=5. 5 watts of input power FROM the amplifier is being converted to sound. The remaining 995 watts of that power is being dissipated as HEAT, IN THE VOICE COIL. Whether the coil is moving or not, that additional 5 watts, if not being "turned into sound" (because the sound isn't happening, right?) will NOT thermally stress the voice coil. It can't happen. Before you say "Yeah, but woofers move a lot, and that cools the voice coil", consider a 200 watt mid-range or a 100 watt tweeter... Those voice coils don't move very much at all, for "cooling". And the math still applies exactly the same.

2: Steven mentioned the automatic low-pass function of a woofer's voice coil, this causing the power available from the amplifier to become less and less. The inductance of the coil will simply limit the power applied, and as with all inductors, (a device the resists high-frequency CURRENT, the other half of the power formula - voltage will remain the same, but the inductance resists the current - without which, there is no POWER, or HEAT) the more power you apply, the more it will resist that power, as the resistance increases. Additionally, the higher the frequency, the more that inductance will try to resist that power even further. A 6dB low-pass filter. Simple as that. By the time you reach 1000Hz, from a reference of 500Hz, the POWER APPLIED will be 6dB lower, or 1/4 the power applied, even if the amplifier is still providing the SAME VOLTAGE. Notice that I am NOT saying anything about how much SOUND the woofer cone is making, I am referring specifically to power levels, expressed in dB.

You simply CANNOT DAMAGE A WOOFER just by feeding it high frequencies, within it's power specification. If you overpower it, THEN you can obviously damage it, but that damage WILL BE FREQUENCY INDEPENDENT! It will be thermal damage. Period.

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Posted By: audiocableguy
Date Posted: July 30, 2007 at 6:08 PM
I was refering to this statement I found faulty:

"I have to say I disagree as high frequency through a sub still puts the same power to it, but the cone travels less resulting in the coils to get hotter quicker which can cause warping"

This is the quote I had sent as part of my question to JL. I got a little delete happy.







Posted By: DYohn
Date Posted: July 30, 2007 at 7:55 PM

audiocableguy wrote:

I was refering to this statement I found faulty:

"I have to say I disagree as high frequency through a sub still puts the same power to it, but the cone travels less resulting in the coils to get hotter quicker which can cause warping"

This is the quote I had sent as part of my question to JL. I got a little delete happy.

Yes, you are correct, the statement you just quoted is completely wrong.



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