How much power do your speakers need? Is low power or high power amp more dangerous?

[AcuDefTechGuy]

This question is asked all the time - probably like every week.
This topic has discussed many times, and AH has written articles on this topic.
But every now and then, it doesn’t hurt to revisit this topic and open a new thread.
I will copy and paste some recent posts and hopefully we will get more people involved in this discussion.

 

[AcuDefTechGuy]

Help me me understand this. I’m hearing 225 watt amp is plenty for a 45-300 watt speaker. Then I’m hearing 600 watts amp is better for the 45-300 watt speaker. I’m confused. Been watching Gene’s video on amps and get it right.

If I owned speakers rated for 45-300W, I would be good with 100-200 WPC amp.
The salient thing is to never play extremely loud.
But if you're asking if too much power is more dangerous for your speakers, that's another hot topic that's been debated forever.
This is my take on this subject based on my studies at the University of Google.
What damages speakers?
1. The actual clipping or distortion?
2. The actual POWER/ENERGY being sent to the speakers?
The answer is the actual ENERGY/POWER being sent to the speakers causing Thermal and/or Mechanical damages.
For example, if a speakers has been tested to truly handle 900W, a 10 WPC amp will NEVER be able to damage the speaker. However, a 500W amp could damage this speakers if the amp clips.
What happens to the POWER output to the speakers when the amp clips? The power output could DOUBLE. So a 300W amp could output 600W when it clips. A 500W amp could output 1000W.
So if your speakers can handle 300W and your 300W amp clips, your speakers could get 600W of "clipped" power/ENERGY. Thus, your speakers would be fried.
That's my take from my studies at the University of Google.
For full disclosure, I have never ever blown a speaker in my life.

 

[AcuDefTechGuy]

ShadyJ posted:

The danger is that when an amplifier clips, the energy in the voltage waveform gets shifted up in frequency, and a lot more energy gets dumped into the tweeter which isn't able to handle nearly as much current as the woofer. Clipping causes harmonic distortion, and the more distortion there is in a signal, the more energy gets shifted upwards in frequency. While a speaker might be rated for 150 watts for example, that is probably a spec for a broadband signal. The tweeter in such a speaker might only be able to handle 10 or 20 watts, so if you feed it 150 watts, especially in a very high frequency, it will overheat the voice coil. Clipping kills tweeters.

 

[AcuDefTechGuy]

So the main problem is the energy going to the Tweeter.

If the amp clips, additional power may be shifted toward the Tweeter.

But even if the amp doesn't clip, the if the tweeter gets more than 20 or 30 Watts, it would still overheat the voice coil.

Case#1.
Speaker is rated for "500W". Amplifier is 200 Watts.

Silk Dome Tweeter Power Handling (ScanSpeak 9500):
https://www.scan-speak.dk/datasheet/pdf/d2905-950000.pdf

100h RMS noise test = 150 W
Long-term Max power = 460 W

If the amp clips, up to 400W goes to the total speaker (all drivers). But perhaps a lot of that 400W goes to the Tweeter.

In this case, the tweeter might possibly handle the clipped energy since the peak power handling is 460W.

 

[AcuDefTechGuy]

Clipping kills tweeters.

Case#2.
Speaker is rated for "500W". Amplifier is 200 Watts.
Diamond Dome Tweeter Power Handling (Seas Excel T29D001):
https://www.madisoundspeakerstore.com/diamond-dome-tweeters/seas-excel-t29d001-diamond-dome-tweeter-matched-pair/
Short-term = 150W
Long-term = 55W
If the 200W amp clips, a lot of the possible 400W could go to the Tweeter. Short-term or long-term, this tweeter is fried.
But what if the amp is 1,000W and doesn't clip, but volume is almost at max? Couldn't 200W of the 1,000W amp go to the tweeter anyway and fry the tweeter even if the amp NEVER clips?
Or for long-term, couldn't more than 75W of power go to the tweeter even if the amp never clips?

 

[AcuDefTechGuy]

M Code posted:

In my experience in working with some of the chief engineers for certain major well-respected audio brands of quality loudspeakers... They have all told me high output power is not what destroys a loudspeaker but rather distortion.... So in reality more loudspeakers are destroyed with low-powered amplifiers rather than high-powered... This is often debated by less experienced people.. But the standard use-case is when a low-powered AVR is pushed hard(tone controls on boost). And then will output alot of distortion and by the time listener has reacted the loudspeaker has already been damaged.

 

[AcuDefTechGuy]

In my experience in working with some of the chief engineers for certain major well-respected audio brands of quality loudspeakers... They have all told me high output power is not what destroys a loudspeaker but rather distortion.... So in reality more loudspeakers are destroyed with low-powered amplifiers rather than high-powered... This is often debated by less experienced people.. But the standard use-case is when a low-powered AVR is pushed hard(tone controls on boost). And then will output alot of distortion and by the time listener has reacted the loudspeaker has already been damaged...
Just my $0.02...

Are they saying just the distortion itself, regardless of the Power or Energy going to the drivers, is causing all the damage?
I assume they mean "a lot of distortion" in the form of "clipping" that causes more ENERGY (and high-frequency energy shift) to go to the drivers (especially tweeters).
But it makes sense to me that the excess ENERGY is what causes the damage.
If distortion occurs but the resulting energy is less than the limits of the drivers, how would this damage the drivers?
Wouldn't AVRs have built-in speaker protection circuits that would cause the AVR to go into Protection Mode if clipping occurs?
The Tone Controls point is interesting. I do know some people who love to use Tone Controls and Manual EQ to boost certain frequencies. If they were to boost the Treble frequencies, that could definitely push even more Energy toward the tweeter.

 

[AcuDefTechGuy]

ShadyJ posted:

Nature of the signal matters here. These drivers can handle a lot more power in short bursts than continuously. The drivers can be destroyed not just by overheating, but also by over-excursion. Obviously, over-excursion happens at lower frequencies where overheating is more likely at higher frequencies, so the frequency of the signal matters. So all of these specs are a bit ambiguous. They are ball-park, rounded-off numbers, not precise points of failure. Furthermore, its not the distortion itself that harms the drivers, but just receiving too much current. The driver doesn't know that the signal is distorted. A lot of music is filled with intentional distortion anyway that isn't much different than what the voltage waveform looks like with amp clipping anyway. What is more, measures can be taken within the crossover to protect the tweeter from too much current, such as the implementation of polyfuses. The bottom line is that if you are playing your content loud, and something sounds off, you should back down on the volume right away right away.

 

[AcuDefTechGuy]

Very interesting about the intentional distortion in music that looks like the waveform amp clipping.

Woofer = Mechanical (excursion) Damage
Tweeter/Midrange = Thermal (heat) Damage

Any speakers out there using poly-fuses to protect the tweeters? I heard the RBH speakers have tweeter protection in their crossovers.

 

[AcuDefTechGuy]

shadyJ posted:

Well, both the woofer and tweeter can be overdriven with excursion or overheated with thermal overload. It all depends on what signal they are being fed.

RBH uses polyfuses in their speakers, to name one manufacturer.

As far as more or less power being more dangerous, it's not so much sheer quantity as where and how that power is being distributed.

Regarding an Audioholics article, there already is a great series: Loudspeakers and Power Handling: Parts I, II, and III

 

[AcuDefTechGuy]

PENG posted:

I can tell you one thing for sure that a 300 W/500 W 8/4 ohm rated power amplifier will have a much greater chance of damaging the tweeter of a speaker than a 125 W rated AVR would, in the wrong hands.

I understand M Code's point, but as you alluded to, we really don't know the full context of his conversations with those "chief engineers".

When an engineer answers a technical question, he/she may not always fully understood what is being asked, and some of the so called engineers may not even be engineers qualified to answer the specific questions correctly.

For example, he/she may be a loudspeaker design specialist in crossovers and enclosures, but may not have a strong background in all things related to power, energy, harmonics, their inter relationship, heating effects etc.


PENG posted:

I would also add that the rated voltage of a 200 W amp is going to be 1.414X that of the 100 W amp, all else being equal. So even based on the scenario when a tweeter is damaged by a badly clipped signal, a 100 W amp has lower odds because one would hear the warning sign, i.e. audible distortions from clipping much sooner and at a lower voltage, i.e. lower current. Again, I am not drawing conclusion, just saying let's not generalize, as it truly depends, on many things.

 

[AcuDefTechGuy]

Verdinut post:

But the 100 w amp will clip faster and then, when it starts clipping, it' may well be too late. Damage is most likely done to the tweeter.

The odds for the more powerful amp are that it would damage the woofer and mid-range drivers when they are driven beyond their x-max and power handling capacities, and quite possibly without any damage occuring to the tweeter because it is operating within its limits without any clipping.

 

[TLS Guy]

I have a number if observations.

It is power that kills speakers.

A manufacturers specs about most things and power in particular mean almost nothing.

The power handling of most domestic speakers is a lot less than people think and manufacturers claim.

Loudspeakers are destroyed in different ways.

Tweeters handle very little power and if you take one apart you would see why. To be a decent tweeter it has to have very light moving parts, among other things. that means very fine VC wire, and so easy burn out. For most music the power required diminishes rapidly above 2.5 K Hz. However if you clip an amp then the power goes up rapidly in the tweeter power band. So clipping is deadly to tweeters. So for tweeters lower power amps are potentially deadly. However idiots who can not' hear distortion, or actually like it, will probably take out tweeters with anything.

The above is just one of the reasons why I favor wide band drivers and a higher crossover points to tweeters.

The power in the midrange for most music is much higher than most people realize. So three ways are a problem. There are precious few dedicated midrange drivers than can really take the power required. On the OEM market probably less than a handful. That means using two drivers, usually, for high power handling. Another problem is that there is no bass to keep the VC moving with large excursion which is some protection against thermal burnout. On the whole unless we are talking about high end speakers, a two way or 2.5 way is much more likely to have better power handling.

Woofers of all types are prone to not only thermal damage but also mechanical damage. It is the lowest frequencies most likely to cause mechanical damage. This is where subs can help. Subs off load smaller woofers and bass/mids a lot, power amps not much, negligible in fact.

As I have said before high powered speakers are expensive formidable affairs.

In my experience it really is the midrange where most speakers are limited. A symphony orchestra, especially combined with a large chorus, needs a power bandwidth in the midrange that few speakers have. That is one of the greatest impediments to realistic and effortless reproduction. When you hear an accurate set of speakers that really can handle those sort of forces, it is a total revelation. We obsess far to much about subs and tweeters and not nearly enough on that crucial midrange where the power really is and the ear is most sensitive.

 

[Danzilla31]

I have a number if observations.

It is power that kills speakers.

A manufacturers specs about most things and power in particular mean almost nothing.

The power handling of most domestic speakers is a lot less than people think and manufacturers claim.

Loudspeakers are destroyed in different ways.

Tweeters handle very little power and if you take one apart you would see why. To be a decent tweeter it has to have very light moving parts, among other things. that means very fine VC wire, and so easy burn out. For most music the power required diminishes rapidly above 2.5 K Hz. However if you clip an amp then the power goes up rapidly in the tweeter power band. So clipping is deadly to tweeters. So for tweeters lower power amps are potentially deadly. However idiots who can not' hear distortion, or actually like it, will probably take out tweeters with anything.

The above is just one of the reasons why I favor wide band drivers and a higher crossover points to tweeters.

The power in the midrange for most music is much higher than most people realize. So three ways are a problem. There are precious few dedicated midrange drivers than can really take the power required. On the OEM market probably less than a handful. That means using two drivers, usually, for high power handling. Another problem is that there is no bass to keep the VC moving with large excursion which is some protection against thermal burnout. On the whole unless we are talking about high end speakers, a two way or 2.5 way is much more likely to have better power handling.

Woofers of all types are prone to not only thermal damage but also mechanical damage. It is the lowest frequencies most likely to cause mechanical damage. This is where subs can help. Subs off load smaller woofers and bass/mids a lot, power amps not much, negligible in fact.

As I have said before high powered speakers are expensive formidable affairs.

In my experience it really is the midrange where most speakers are limited. A symphony orchestra, especially combined with a large chorus, needs a power bandwidth in the midrange that few speakers have. That is one of the greatest impediments to realistic and effortless reproduction. When you hear an accurate set of speakers that really can handle those sort of forces, it is a total revelation. We obsess far to much about subs and tweeters and not nearly enough on that crucial midrange where the power really is and the ear is most sensitive.

I can attest to power ratings being a little inflated by manufacturer's I had a pair of towers rated 300 watts RMS. Was running on my onkyo one day 2 channel stereo for music that onkyo put out 140 watts ×2 I believe I didn't even have it cranked all the way. I stopped it after a bit because it looked like the woofers on those towers were dying in miserable miserable ways. Way to close to exceeding they're limits and damaging those drivers. I thought to myself yeeeaahh 300 watts with a sub maybe. Too bad that wasn't on the brochure. Lol

 

[M Code]

Lets not overthink this...
When matching loudspeakers to an AVR (or amplifier) the question asked most frequently is not the power handling question but rather about impedance be it 8 or 4 Ohms.. The major breakdown today for loudspeaker failure is due to fewer people evaluating/understanding the specs for loudspeaker sensitivity, driver size, room size, average listening SPL, affordable budget...
As stated previously the reason more loudspeakers are destroyed by a low powered amplifier are simple economics.. Keep in mind:

• 74% of AVRs sold today have amplifiers rated @ 85 watts or less
• 88% of HT systems sold today are with smaller satellite/subwoofer loudspeakers, typically requires more output power to achieve a target SPL vs. full-range loudspeaker
• >78% of the AVRs sold today are by less knowledgible staff either through the internet and/or big-box retailer
• More & more audio sources are utilize an audio compression protocol such as MP3 or Dolby Digital

Bottom line, the higher end market segment are for the most part simply more knowledgible....
Plus typically their loudspeakers tend to be more expensive and designed to handle more abuse.

Just my $0.02..

 

[Out-Of-Phase]

I have blown the tweeters on my old 3-way speakers many times a long time ago.

1977 Kenwood receiver, 30wpc rms.

How were the tweeters blown?

I believe by turning up the volume too loud on very dynamic demanding music.

Receiver not powerful enough?
Music listener not smart enough?
All of the above?

I think, all of the above.

 

[Mikado463]

I can attest to power ratings being a little inflated by manufacturer's I had a pair of towers rated 300 watts RMS. Was running on my onkyo one day 2 channel stereo for music that onkyo put out 140 watts ×2 I believe I didn't even have it cranked all the way. I stopped it after a bit because it looked like the woofers on those towers were dying in miserable miserable ways. Way to close to exceeding they're limits and damaging those drivers. I thought to myself yeeeaahh 300 watts with a sub maybe. Too bad that wasn't on the brochure. Lol

and with that how likely was it that your receiver was actually at fault (unable to provide non-distorted power) ?

 

[Mikado463]

Lets not overthink this...
When matching loudspeakers to an AVR (or amplifier) the question asked most frequently is not the power handling question but rather about impedance be it 8 or 4 Ohms.. The major breakdown today for loudspeaker failure is due to fewer people evaluating/understanding the specs for loudspeaker sensitivity, driver size, room size, average listening SPL, affordable budget...
As stated previously the reason more loudspeakers are destroyed by a low powered amplifier are simple economics.. Keep in mind:

• 74% of AVRs sold today have amplifiers rated @ 85 watts or less
• 88% of HT systems sold today are with smaller satellite/subwoofer loudspeakers, typically requires more output power to achieve a target SPL vs. full-range loudspeaker
• >78% of the AVRs sold today are by less knowledgible staff either through the internet and/or big-box retailer
• More & more audio sources are utilize an audio compression protocol such as MP3 or Dolby Digital

Bottom line, the higher end market segment are for the most part simply more knowledgible....
Plus typically their loudspeakers tend to be more expensive and designed to handle more abuse.

Just my $0.02..

true ........

 

[Mikado463]

I have blown the tweeters on my old 3-way speakers many times a long time ago.

1977 Kenwood receiver, 30wpc rms.

How were the tweeters blown?

I believe by turning up the volume too loud on very dynamic demanding music.

Receiver not powerful enough?
Music listener not smart enough?
All of the above?

I think, all of the above.

again, agreed, been there, done that as well ........

 

[Danzilla31]

and with that how likely was it that your receiver was actually at fault (unable to provide non-distorted power) ?

Honestly? I think it was both if you get down to it probably non accurate specs with the speakers and non accurate specs with the reciever. It's not like I was cranking it to reference or past. You never can tell with manufacturers these days. Best defense against that is my ears and eyes. That's what saved me there. It didn't sound right and it sure as hell didn't look right so what to do? Ya turn it down and never try that s$!#t with that particular gear again.

My biggest peeve is when manufacturers on speakers will say minimum 50 to 300 watts. Really? What exactly does this mean? I'd like a RMS precise measurement please. What can they really handle on a regular basis and still have room for dynamics swings and everything else? But you call them and they kind off dance around the question. It doesn't get better to some extent until you get to higher end audio. Sometimes.

I also hate that +- 3db. Really? Just spit it out fellas. Where can this baby really play too and where does it fall off at. If I like the speaker I'm gonna buy it anyways. I really don't care about the useless extension down to 38hz I can t hear that I'll be driving a sub for anyways. I get that you pretty much can measure where it falls off at by the +- measurement. But only if your learning like from here or from others. A lottof regular consumers just dont know what things like that mean. And that's how they get themselves in trouble

But it must work cause there making sells. Which I guess is why they fudge the numbers. Just the way things go I guess. I'm glad to be learning what I'm learning from here so I can learn to sift through and look for the info I really need.