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Discussion Starter #1
I am absolutely positively sick of the conflicting information on this. I want a clear, concise, and for the love of God, SIMPLE explanation.


Which s worse?


Having speakers be overpowered or underpowered?


Thank you.
 

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Simple answer. If your speaker does need more power than your amp can deliver for the desired playback volume...than you run your amp into clipping and hopefully thermal cutout.


If your amp can deliver more power than your speaker can handle for your desired playback volume you might drive your speakers in to unspeakable distortion - for a short while - until you release smoke from the voice-coils. Once smoke is released - you cannot put it back.
 

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Quote:
Originally Posted by Max Burleigh  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23194368


I am absolutely positively sick of the conflicting information on this. I want a clear, concise, and for the love of God, SIMPLE explanation.


Which s worse?


Having speakers be overpowered or underpowered?

It's a poorly formed question because there is no practical need to struggle with either problem.


The first and foremost problem with underpowering speakers is loss of sound quality due to clipping, pure and simple.


In another thread over in the Speakers forum we calculated the amount of power required for reference levels in a typical listening room with modern high quality speakers and found that an average AVR can do the job without clipping, audible distortion or loudspeaker damage


It takes something like 25-50 wpc to achieve reference levels (85 dB SPL at the listener's ears) with ample headroom (14 dB) for most recordings depending on room acoustics.


If you have speakers with lower efficiency than average (say 80 dB SPL/W), a larger room, a deader room, more dynamic recordings, or a desire for louder music than be prepared to throw significant power (probably measured in killowatts) at the problem. It takes 10 times the power to create the impression of "twice as loud". If you choose an 80 dB/W loudspeaker over a 90 dB/W loudspeaker then you need 10 times the power. It takes 4 times the power to handle recordings that need 20 dB headroom than 14 dB headroom. From 2 to 4 times more power can be needed if your room is larger or deader than average.


There are a lot of variables that change for each and every audiophile. It is also true that most low efficiency loudspeakers (such as many planar types whether electrostatic or magnetic) can't take kilowatts of power. If you need high SPLs you need to adjust your technological, especially loudspeaker choices accordingly.


There is no sonic advantage to using a 5 kilowatt power amp or even a mere 500 watt amplifier to deliver 50 watts to a loudspeaker. If there is no audible distortion then you won't hear any except in terms of your expectations.


If you really do need far more amplifier power your options in the home audio market seem to fade as you go about 200-500 watts. It needs to be understood that 200 watts is only 3 dB more than 100 watts and 100 watts is about what your average AVR can produce. If you want to understand what 3 dB more sound is like, take advantage of the calibrated volume control on your AVR and crank your system up by 3 dB and see what you think. Not so much.
 

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Discussion Starter #4
Okay, let me rephrase this then. There is a lot of conflicting information scouring the monstrosity that is the web, regarding speakers and amps. And lemme put it this way, when it comes to audio, it would be an honor for one to even call me a novice at it.



Many sources claim that overpowering a speaker with an amp is fine as it will simply clip and distort at high levels which is unwanted anyways, so it is rare speakers would ever be damaged because of it. Many other sources say that it is worse to have a speaker be underpowered as it will cause clipping, distortion, and speaker damage (obviously unwanted things as well). So with all this conflicting information I am seeking a simple (as possible) answer with palpable evidence behind it.


And I am referring to car audio in particular when it comes to this, I should've mentioned that, I apologize.



For home audio though, it would also be nice to have a lesson on matching speakers with receivers
 

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Hi Max,


I never liked those terms, "overpowering speakers" or "underpowering speakers", because the former implies that you are driving the speakers beyond what they are meant to take, and the latter implies that you are not driving them enough to produce adequate sound. In fact, it is meant to imply having an amp that is rated for more power than the speakers, and having an amp that is rated for less power than the speakers, respectively.


But if you think about it, those ratings do not really relate to each other at all. They need to relate to the power that you wish to use to listen to your music. If you need 100 watts to bring the volume up to where you need it, then both the speakers and the amp need to be rated above that. It really doesn't matter which is rated higher, because you shouldn't reach that point. If you do reach your system's limit, "underpowered" or "overpowered" only determines which component is going to produce distortion.
 

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your speaker is likely specified at the power that will make it die from heat over a long ish period.


BUT the speaker contains both a woofer or multiple woofers and a tweeter. Real world content, the tweeter gets at most aroun 25 percent of total power. Tha means you can probaly kill a 100 watt speaker's tweeter with 50 watts or less of a pure tone at, say 10,000 Hz. B ecause in that 100 watt speaker, the tweeter is not expected to see more than 25 watts.


Presumably you recognize that a more powerful amp can be louder. That's the beginnign of understanding that how loud a speaker plays depends on how much power is applied to it.


The inverse of this is that a 100 watt or 200 watt or 10000 watt amp is not putting out full power into the speaker every second, because sometimes the sound is quieter, and sometimes you turn down.


to destroy a speaker with clean power you probably have to use an amp that is specified to deliver clean power in excess of the speaker's capability.

To destory a tweeter with distorted power you need an amp that is delivering enough clean power to exceed the tweeter's capacity or that is distorted enough to deliver enough high frequency energy to the tweeter to kill it.


Either way the speaker is damaged by too much power. Turning off the amp does not hurt the speaker, so it only stands to reason that 'too little power" won't kill it.


Guitar players from sy Clapton onward have used amplifiers that were distorting in the preamp and power amp sections and (see Hendrix) often using a soid state pedal to further distort the signal before it ever sees the amplifier. Yet not only do their speakers survive, butb modern PAs that carry pretty much all the sound that reaches an audiecne also survive the "onslaught" of distortion. Distortion is not per se (oooh it's Latin, not "say") will not harm a speaker. Until the total output of the device reaches power levels above what the speaker is designed to handle.


Every amp will put out significantly more power than it is rated for. Go to Stereophile.com and look at some amp lab tests. They all have rapidly rising distortion above some "knee" and they all are specified with relatively low distortion on that rising part of the power versus distortion curve. distortion will come with any amp if you hit it hard enough with the input signal. At some point, depending on the original signal, the harmonics added by the amp's distortion may be enough to damage the speaker, particularly the tweeter.


Of course if you plut your speaker directly into a 120 Volt power outlet in your wall, or hit it hard enough with an amp's clean output you might damage ith through a number of means. You can force the voice coil to travel too far, which will kill the woofer. You can overheat the system damaging the voice coil, etc. etc. Plenty of 'fun" videos on youtube of speaker killing activities.
 

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Underpowering will ALWAYS make your speakers last longer-AS LONG AS YOU DON'T CLIP THE AMP!!!!!!!!!!!!!!!!!!


When you start to clip all sorts of things change. The average power goes up etc.


Also it is NOT the power that the amp has or how loud you run it-but RATHER-how long the heating is applied to the voice coil.


You could run the same size amp and run it to the edge of clipping-and with one style of music tear up the speakers all the time-and with another style of music be just fine.


It depends on the dynamic range and AVERAGE heating that is applied to the loudspeakers.


There is no easy answer.


The 2 things that kill a speaker are tow much power for to long and overexcursion-causing the cone to jump out of the VC gap. Underpowering will almost never be able to cause overexcursion-while overpowering possibly can-depending on a lot of factors.


The biggest thing is to LISTEN to your system!!!!!!!!!!!!!!! If it is distorting or making noises-it is telling you to TURN IT DOWN! If you don't listen-you will damage it.


But some people like distortion-or the music is so distorted already you can't tell the difference-so that makes it harder on some styles/preferences




Look at a subwoofer-if you play "normal music" (whatever that is), at the rated power level you will be fine.


But if you play music that has a lot of sinewaves-low crest factor etc-you will let the smoke out real quick-even with the same peak levels-because the AVERAGE heating is much more with that type of music.
 
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Quote:
Originally Posted by Max Burleigh  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23194368


I am absolutely positively sick of the conflicting information on this. I want a clear, concise, and for the love of God, SIMPLE explanation.


Which s worse?


Having speakers be overpowered or underpowered?

Please define underpowered and overpowered.


By underpowered do you mean using an amp whose rated power output is less than the maximum rated power for the speakers?
 

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Quote:
Originally Posted by Max Burleigh  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23194368


I am absolutely positively sick of the conflicting information on this. I want a clear, concise, and for the love of God, SIMPLE explanation.


Which s worse?


Having speakers be overpowered or underpowered?


Thank you.
Every complex question is easily answered by a simple-easy to understand WRONG answer.


You are talking about a very complex subject-there is no "simple" answer that fits every need and situation and musical style.


Let's say you have a "100watt" (whatever that rating REALLY means-which is a whole different complex question/situation) speaker.


Person can can use a 50 watt amp (again-how is that rating ACTUALLY determined-yet another complex situation) and tears up the speaker all the time. Person B uses a 400 watt amp and runs it to on the edge of clipping-yet he does not tear up the speaker.


It all comes down to dynamic range-average heating and so forth-and every situation is different.


The further you look for the "simple" answer-the more vague the answers are going to be.


Sorry-but that is just the way it is.


Think of it like this-the mileage rating on your car. Do you get the exact numbers it is rated for? no. Why-are the ratings wrong? no. But they are for a very specific set of circumstances-and unless you drive exactly like those circumstances you will not get the same milege. You may get more-or less. But YOUR habits/loads/roads are different than those in the test.
 

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Quote:
Originally Posted by Ivan Beaver  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23202040

Quote:
Originally Posted by Max Burleigh  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23194368


I am absolutely positively sick of the conflicting information on this. I want a clear, concise, and for the love of God, SIMPLE explanation.


Which s worse?


Having speakers be overpowered or underpowered?


Thank you.
Every complex question is easily answered by a simple-easy to understand WRONG answer.


You are talking about a very complex subject-there is no "simple" answer that fits every need and situation and musical style.


Let's say you have a "100watt" (whatever that rating REALLY means-which is a whole different complex question/situation) speaker.


Person can can use a 50 watt amp (again-how is that rating ACTUALLY determined-yet another complex situation) and tears up the speaker all the time.

How does someone tear up a 100 watt speaker with a 50 watt amplifier by using it in a way that would not cause even more damage if a 400 watt amplifier was used instead?
 

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I think the misunderstanding comes from realizing what causes a speaker to blow in the first place. When a amp clips, it offers a square wave which is highly decremental to speaker life. In fact, amp clipping causes more speaker blow outs than clean high power does. So lets set an order of speaker health to speaker detriment.


1) clean power within the rating of the speaker - no issues

2) a distorted signal below the power rating of the speaker - power levels below a speaker rating can still blow it up if the signal is clipping.

3) a distorted signal above the rating of the speaker - this will nearly always result in a blown speaker eventually


So in answer to the OP's question, id say higher power is better IF you can monitor it from clipping and keep it below the speaker power rating (average power). The extra dynamic headroom that a higher powered amp offers is a good thing in that all speakers can handle more power than their rating for very short periods of times, typically the length of dynamic peaks. If you have 100watt speakers and a 100watt amp, any signal that exceeds the power rating of the speaker will be a clipped signal. If you have a 100watt speaker with a 200 watt amp, dynamic peaks up to +3 will still be clean and the speaker can probably handle short term peaks of +3db.


Now typically, peaks can reach +10db compared to that of the average power level. So lets go back to our example(s) of 100 watt speakers with a 100 watt amp and a 200 watt amp. The 100 watt amp's average power level needs to be kept to a 10 watt average if one is to allow +10db headroom for peaks. With the 200 watt amp, you could go to a 20 watt average power level without clipping a 10db peak.


Much depends on the speaker in question. Some can exceed their rated power for peaks better than others. The drivers and the crossover design determine these in absolute terms.


But I will add that what theory says is different than typical application. That is, people with big amps tend to turn them up to their limit, at least on occasion. Or to the point where they hear clipping and then back off. Problem is, dynamic peak distortion will occur before you can hear it. And a big amp clipping is no doubt worse than a small amp clipping.
 

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Quote:
Originally Posted by Ivan Beaver  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23199040


The biggest thing is to LISTEN to your system!!!!!!!!!!!!!!! If it is distorting or making noises-it is telling you to TURN IT DOWN! If you don't listen-you will damage it.

Emphasis mine.


Ivan, spot on.


This is key, and seemingly so, so simple. Listen for the onset of the first hint of non-linearity. Be it the subtle onset of audible compression, or the more nasty forms of distortions. Listen, when one encounters the edge of the linear envelope, back off a touch and enjoy. Note the drive level, and if ever there's a source material scenario whereby objectionable non-linearity occurs, again ...back off a touch.


This has bothered me somewhat since I first became an enthusiast back in the mid 70's. Someone irresponsibly pushing, operating an audio system of any size past it's linear limitations. Anyone can notice the objectionable garbage, but detecting the more subtle compression onset and it's distortion profile is perhaps more of an acquired skill. Once pointed out, it's easy to detect.


Admittedly, different spectral content is affected to varying degrees due to psycho-acoustic perception. Hell, simply an out of balance system is objectionable. Listen to a state of the art PA rig full tilt boogie. Crystal clear, ideally aligned, high clarity and impact. Turn all drive sections off other than the mid-highs and highs.
Everyone plugs their ears in discomfort, .. however a moment ago everyone was fully enjoying the system's clean and low distortion output.


Back OT, ... good point Ivan, simply listen.
 

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Quote:
Originally Posted by jim19611961  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23202253



When a amp clips, it offers a square wave which is highly decremental to speaker life. In fact, amp clipping causes more speaker blow outs than clean high power does.
Quote:
Demonizing square waves is one of those things that may make intuitive sense, but doesn't stand up to technical analysis.


The salesman's patter goes on and on about all of the harmonics in sharp-edge square waves. Thing is that square waves can actually have lower harmonic content than some music!


Here's an example:




In this analysis, the upper signal is the same as the lower signal except that it is amplified by 1000 times but clipped at the same power level as the lower signal which is just below the clipping point.


The first surprise is that even though the amplifier was running just below clipping for the lower undistorted signal, , the energy in the distorted signal coming out of it was able to increase by an additional 22 dB. This is a more than 100 times increase in power, which is very significant to say the least!


If the amplifier had been rated at a high power level then the amount of power coming out of the more powerful amplifier would have been increased by 22 dB plus the difference in power rating between the two amplifiers. IOW the more powerful amplifier would have damaged the speaker even more severely.


The point that I want to make is that of course the clipped signal has far more energy in it at all frequencies, simply because it is louder. What some may find interesting is the fact that the amplifier was able to provide signficiantly more power to the speaker once it started clipping.


Yes, there is some shifting of energy towards the higher frequencies, but it pales in comparison to the energy that is added simply because the signal became louder.


The bottom line is that if you want to avoid damaging your speakers, listen to the music as you adjust its volume, and stop turning it up once it starts sounding distorted. This is the same common sense suggestion that was made above by FOH and Ivan, and all my colored pictures do is show a few more details about the process.
 

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Quote:
Originally Posted by jim19611961  /t/1467908/underpowered-vs-overpower-speakers-which-is-worse#post_23202253


I think the misunderstanding comes from realizing what causes a speaker to blow in the first place. When a amp clips, it offers a square wave which is highly decremental to speaker life. In fact, amp clipping causes more speaker blow outs than clean high power does. So lets set an order of speaker health to speaker detriment.

In every case speakers are damaged by receiving too much power. The relevant question has always been "Where does the power come from?"


When you push an amplifier further into clipping its power output continues to rise which may seem counter intuitive. We tend to think of clipping as a brick wall above which amplifer cannot increase, but because of the complex nature of musical waveforms, it is possible for the output of a power amplifier to increase significantly even though it is clipping.


This counter intuitive behavior has been explained by the fact that clipping may change the spectral contents of music and increase the proportion of energy at higher frequencies. This may happen, but the stronger effect is simply an increase in power levels at all frequencies. This agrees with the observed fact that speaker damage may involve woofers more often than tweeters. I've personally replaced far more woofers than tweeters in speakers that have been brought to me for repair.
Quote:
1) clean power within the rating of the speaker - no issues

Agreed.
Quote:
2) a distorted signal below the power rating of the speaker - power levels below a speaker rating can still blow it up if the signal is clipping.

Whether this is true or not depends on the skill with which the speaker's power ratings were determined. It is not impossible for music to have a similar or even more potentially damaging set of frequencies in it as a heavily clipped wave.



Quote:
3) a distorted signal above the rating of the speaker - this will nearly always result in a blown speaker eventually

As will an undistorted signal that is above the rating of the speaker. Speakers don't have sensors for distorted cooties on inbound signals. All speakers see is a signal with varying amplitude and varying selection of frequencies.


One difference between less powerful amplifiers and more powerful amplifiers is that more powerful amplifiers will put out more power without audible distortion. Audible distortion is a signal to the listener that his system is in distress and that he should back the volume down. More powerful amplifiers will deliver more power to the speaker before giving the listener this kind of feedback.
Quote:
So in answer to the OP's question, id say higher power is better IF you can monitor it from clipping and keep it below the speaker power rating (average power). The extra dynamic headroom that a higher powered amp offers is a good thing in that all speakers can handle more power than their rating for very short periods of times, typically the length of dynamic peaks. If you have 100watt speakers and a 100watt amp, any signal that exceeds the power rating of the speaker will be a clipped signal. If you have a 100watt speaker with a 200 watt amp, dynamic peaks up to +3 will still be clean and the speaker can probably handle short term peaks of +3db.

Is r the above is good or bad? The 100 watt amplifier will give you a system that starts sounding bad when you try to send too much power to the speakers. The lower powered amplifier will cue the listener to back off sooner.
 
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