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Discussion Starter #1 (Edited)
I wanted to start collecting some information pertaining to speaker damage from amplifier power. While it's certainly common practice to match the rated power output from the amplifier to the power handling abilities of the speaker, it's possible to both over power and under power a speaker without issue.

Many users ask about speaker damage (failure) which I feel can be attributed to fairly specific scenarios. Often threads are created asking about using an amplifier rated for less power than the speaker, using an amplifier rated for more power than the speaker, or asking why they destroyed their speaker using less than rated power.

Under powering the driver
You will never damage a speaker by using too little power - period. Applying less power than the driver is rated for will not cause damage provided the speaker is operating within design parameters (see enclosure and crossover below).
However, many enthusiasts don't realize what happens when you have an amplifier that's driven into clipping for extended periods of time. When an amplifier runs out of clean power, either from over-driving the output stage or a lacking electrical system that's not providing proper current/voltage, bad things happen. This is often referred to as distortion, which is technically correct, however distortion doesn't hurt a speaker, either from an over-driven pre-amp section or the material - otherwise anything from Hendrix would destroy our speakers :). When an amplifier "clips" it produces more than its rated power and, if this is more than the speaker is designed to handle, may damage the speaker's voice coil. There are articles linked below that go into more technical detail, but driving an amplifier past its limits for extended periods of time is the only way a speaker can be thermally damaged with a lower powered amplifier. Of course there are variables, as clipping a 25 watt amplifier will never damage a 500 watt speaker, but a 300 watt amplifier that is heavily clipped for extended periods of time may damage that same 500 watt speaker.

Over powering the driver
While it is possible to over drive a speaker and create damage with excessive clean power, this is far less frequent than damage caused when a low powered amplifier is over driven. Due to the transient nature of music, even a high powered amplifier exceeds the driver's capabilities for very brief periods of time which doesn't cause damage. There are two scenarios that will cause damage:

Over powering the driver causing damage from exceeding the physical limits of the driver. Essentially, pushing the driver beyond what the surround and spider can handle causing physical damage or tearing of the components, or bottoming out and damaging the voice coil.

Applying too much power to the voice coil, for example a tweeter, can overheat the voice coil former and causes the adhesives to fail. This takes significant over powering for extended periods of time - while possible this isn't common.

Using the incorrect enclosure (bass/mid bass)
Technically, this is over powering the speaker as the driver is forced to operate outside the design parameters. The enclosure for a speaker is designed to control the movement of the driver and if the enclosure isn't designed correctly, specifically in a vented (ported/bass reflex) or infinite baffle enclosure, the speaker can be physically damaged if it's allowed to play below the tuning frequency. This can be alleviated with a subsonic filter to limit low frequency excursion.

Using incorrect crossover frequency
This is also a form of over powering the driver similar to using the wrong enclosure. Incorrectly applying a crossover to a driver can allow the driver to play frequencies it wasn't designed for and cause damage. This is always (almost?) related to low frequencies whether it's a tweeter playing too low, midrange playing to low or woofer playing too low (band pass or infinite baffle) and causes mechanical damage to the driver. Allowing a speaker to play above the frequencies it was designed for won't cause damage, but it will probably sound bad :) .

Speaker age, physical damage and inferior amplifiers
Speakers age. Components become brittle and don't respond like they did when new - even the most well cared for speakers can suffer from age which is typically a cracking/failing surround and sometimes a sagging spider from improper storage. Additionally, a screw driver that's carelessly thrust through a speaker can cause failure. And, there's information surfacing that some high output low cost amplifiers are damaging drivers due to poor design and tolerance.

Here are a few articles - I may add more over time and invite others to contribute!


-Eric

From Focal - what typically ruins a speaker:
Why do voice-coils burn out?

From Elliot Sound Products - what happens when an amplifier clips:

From Kicker - discussing different enclosure types:
 

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It doesn’t depend. Too little power never damages a speak. When you clip an amp, you cause excessive power, while simultaneously making a speaker unable to cool itself from the excess power.
 

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Discussion Starter #3 (Edited)
It doesn’t depend. Too little power never damages a speak. When you clip an amp, you cause excessive power, while simultaneously making a speaker unable to cool itself from the excess power.
Yes - we both know that .

However I put this together as many people don’t know how an under powered amp can damage a speaker and it’s a common question here.

And - too little power can physically (not thermally) damage a speaker from over excursion or playing below recommended frequency range (i.e. tweeters) which I call out.


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Clipping and underpowered are two separate issues. There is no threat to "underpowering" a speaker. What matters are the following:

-Desired output volume
-Sensitivity of the speaker being high enough to achieve the desired output volume, given the output voltage of the amplifier and the power handling of the speaker in the specific scenario.

If a speaker is "rated for 100w" for example, there is absolutely no issue with using an amplifier that outputs 25w- so long as the desired output volume is reached. On the flip side, there is absolutely nothing wrong with using an amplifier that outputs 300w on the same speaker, so long as the voltage output to the speaker does not exceed its maximum and the speaker is installed and crossed over properly for its intended pass band.

Clipping is to be avoided at any output level whether that is 50 watts less than the RMS of the speaker, or 50 watts higher.


Also, manufacturers rate their power handling differently so you need to be aware of what their spec is. For example, one manufacturer may rate their midrange for 100W when utilizing the recommended crossover of 200hz 24db. Another manufacturer may rate their midrange for 40w power handling but without a crossover and when a crossover is applied it greatly increases that power handling number- perhaps even higher than the 100w rated midrange.
 

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Yes - we both know that .

However I put this together as many people don’t know how an under powered amp can damage a speaker and it’s a common question here.

And - too little power can physically (not thermally) damage a speaker from over excursion or playing below recommended frequency range (i.e. tweeters) which I call out.


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Well your title seems like click bait then. A speaker is not damaged by too little power, ever.

You cannot cause over excursion with too little power, so you cannot damage a speaker physically, or thermally with too little power.
 

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Discussion Starter #6
Well your title seems like click bait then. A speaker is not damaged by too little power, ever.

You cannot cause over excursion with too little power, so you cannot damage a speaker physically, or thermally with too little power.
What do you propose for a title?

When I did this early this morning I had just been in a thread asking this very same question about damaging a speaker with too little power.

In my very first paragraph I stated that you can’t damage a speaker from too little power which we both agree on.

This, as with every forum I’ve been a part of since the 90s, has similar questions repeatedly asked by newer members. One that member learns what they need to know they no longer ask the question, their thread gets buried, and the question is eventually asked again.

Title is click bait in a sense now that you mentioned it. Many members here understand how a speaker is damaged and what can be done to prevent it. While it was early when I created this, I believe it addresses many questions that are often asked (can I under power, over power, and why did I “blow” my speaker using less power than rated).

Thoughts?
-Eric


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What do you propose for a title?

When I did this early this morning I had just been in a thread asking this very same question about damaging a speaker with too little power.

In my very first paragraph I stated that you can’t damage a speaker from too little power which we both agree on.

This, as with every forum I’ve been a part of since the 90s, has similar questions repeatedly asked by newer members. One that member learns what they need to know they no longer ask the question, their thread gets buried, and the question is eventually asked again.

Title is click bait in a sense now that you mentioned it. Many members here understand how a speaker is damaged and what can be done to prevent it. While it was early when I created this, I believe it addresses many questions that are often asked (can I under power, over power, and why did I “blow” my speaker using less power than rated).

Thoughts?
-Eric


Sent from my iPhone using Tapatalk
I think your thread would be good, with edits...

For example:

"Over powering the driver
  1. While it is possible to over drive a speaker and create damage, this is far less frequent than damage caused by under powering a speaker."
This implies that although less frequent, a speaker can still be damaged by under powering it. This isn't true. Damage from clipping isn't from underpowering a speaker, damage caused by clipping is overpowering a speaker.

The title of the thread implies the same.

I think this important to clarify because this distinction is what keeps people confused about the topic.

While I think you are on the right track, there are a couple of things in the thread that need editing, and those things are very important to help teach people the truth (the point of your post), left as is, this thread still implies that underpowering a speaker can damage it.
 

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I have seen several speakers blow in my time and most with the exception of subs had little to do with power. I have seen several subs go, usually it is was because of clipped dirty signal rather than the amount of power. Clipping amps, bass boost on, running a big dirty amp, yes the sub will smoke.

On mids and tweets, usually user error. clipping is one, but the other is running a speaker outside safe crossover points and applying power.

Clipping and too much or too little power are very different. If you have clean signal, running under powered is not an issue. Just the same as if you have clean power and safe cross over points, over powering and headroom are not usually an issue. Start throwing in a clipped/distorted signal to either and you end up with a smoke signal.
 

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I have seen several speakers blow in my time and most with the exception of subs had little to do with power. I have seen several subs go, usually it is was because of clipped dirty signal rather than the amount of power. Clipping amps, bass boost on, running a big dirty amp, yes the sub will smoke.

On mids and tweets, usually user error. clipping is one, but the other is running a speaker outside safe crossover points and applying power.

Clipping and too much or too little power are very different. If you have clean signal, running under powered is not an issue. Just the same as if you have clean power and safe cross over points, over powering and headroom are not usually an issue. Start throwing in a clipped/distorted signal to either and you end up with a smoke signal.
All of those scenarios boil down to excessive power.

Running too low of a crossover sends too much power to a speaker, for the bandwidth it's designed for.

Clipping amps, bass boost, etc. cause too much power.

Clipping itself is harmless, the speaker doesn't care what the wave shape is as long as that wave keeps the speaker below its power limits.
 

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I swear we just did this thread lol.
 

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Discussion Starter #11
I swear we just did this thread lol.
If so - then we should collaborate and creat a sticky.

This is a common question that while parts of it can be complicated the overall message isn’t highly technical.

If I’m able to edit my original post later I will with some of the feedback I’ve received.

-Eric


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I thought I would start collecting some information pertaining to speaker damage from amplifier power. While it's certainly acceptable to match the rated power output from the amplifier to the power handling abilities of the speaker, it's possible to both over power and under power a speaker without issue.

Many users ask about speaker damage (failure) which I feel can be attributed to fairly specific scenarios:
  1. Under powering the driver
    1. Many don't realize what happens when you have an amplifier, typically rated for less than the speaker's capability, driven into clipping for extended periods of time. When an amplifier runs out of output, either from over-driving the output stage or not providing proper current/voltage, bad things happen. This is often referred to as distortion, which is technically correct, however distortion doesn't hurt a speaker, either from an over-driven pre-amp section or the material - otherwise anything from Hendrix would destroy our speakers :)
  2. Over powering the driver
    1. While it is possible to over drive a speaker and create damage, this is far less frequent than damage caused by under powering a speaker. Due to the transient nature of music, even a high powered amplifier exceeds the driver's capabilities for very brief periods of time which doesn't cause damage. There are two scenarios that will cause damage -
      1. Over powering the driver causing damage from exceeding the physical limits of the driver. Essentially, pushing the driver beyond what the surround and spider can handle causing physical damage or tearing of the components
      2. Applying too much power to the voice coil, for example a tweeter, that overheats the voice coil former and causes the adhesives to fail. This takes significant over powering for extended periods of time - while possible this isn't common.
  3. Using the incorrect enclosure (bass/mid bass)
    1. The enclosure for a speaker is designed to control the movement of the driver and if the enclosure isn't designed correctly, specifically in a vented (ported/bass reflex) or infinite baffle enclosure, the speaker can be physically damaged if it's allowed to play below the tuning frequency. This can be alleviated with a subsonic filter.
  4. Using incorrect crossover frequency
    1. Incorrectly applying a crossover to a driver can allow the driver to play frequencies it wasn't designed for and cause damage. This is always (almost?) related to low frequencies whether it's a tweeter playing too low, midrange playing to low or woofer playing to low (band pass or infinite baffle) and causes mechanical damage to the driver. Allowing a speaker to play above the frequencies it was designed for won't cause damage, but it will probably sound bad :) .
  5. Speaker age
    1. Speakers age. Components become brittle and don't respond like they did when new - even the most well cared for speakers can suffer from age which is typically a cracking/failing surround and sometimes a sagging spider from improper storage.

Here are a few articles - I may add more over time and invite others to contribute!

I prefer to refence material written by manufacturers or experts in the field.

-Eric

From Focal - what typically ruins a speaker:
Why do voice-coils burn out?

From Elliot Sound Products - what happens when an amplifier clips:

From Kicker - discussing different enclosure types:
Can you please edit the numbering? It's driving me nuts.
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I realize you used the "buttons" on the forum page to do this, but it didn't work out well. :)
 
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Discussion Starter #13
Can you please edit the numbering? It's driving me nuts.
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I realize you used the "buttons" on the forum page to do this, but it didn't work out well. :)
Lol!

They look fine in a browser but anyone on Tapatalk with OCD is struggling...

-Eric


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It doesnt depend at all.

Leaving out drivers deteriorating from being in the elements.. Overexcursion by too low of a crossover for given applied power, and too much power in general (not to be mistaken for RMS power) is purely what destroys speakers. overexcursion will destroy the driver by bottoming out the coil and/or tearing the surround/spider. too much power will melt or deform the coil.

before anyone replies to this and says "BuT wHaT aBoUt cLiPpInG bRo"... a square wave is equal to 3x the applied power (heat) over a given cycle than a sine wave is. If a speaker can thermally handle 100 watts, and you use a 25 watt rms amplifier and send that driver a signal that is clipped to the moon and back, its still not going to blow, since that will heat the coil as if it were being powered with an unclipped 75 watt signal
 

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A screw driver...

Everyone in this b!tch session missed the obvious :)

Ge0
 
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Lol!

They look fine in a browser but anyone on Tapatalk with OCD is struggling...

-Eric


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And that would be my situation exactly.
 
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Discussion Starter #17
A screw driver...

Everyone in this b!tch session missed the obvious :)

Ge0
I for one have put a screw bit through a surround. Granted it was 20 years ago when I installed but it was a terrible feeling. I've also seen speakers destroyed by various objects in the trunk as well when not protected :) .
-Eric
 

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I for one have put a screw bit through a surround. Granted it was 20 years ago when I installed but it was a terrible feeling. I've also seen speakers destroyed by various objects in the trunk as well when not protected :) .
-Eric
Me too, now I protect the speaker surround with my finger, at least my fingers heal without silicone caulking.
 
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