Can a power amp have too much power, risking damage to a speaker?

@joelepo Wrote:

Can a power amp have too much power, risking damage to a speaker?

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Mike

Of course. Don't try this at home.
My 100 Watt MF integrated completely melted the midrange drivers of a pair of brand new Hyperion speakers.

Thanks much Mike for that info! I'll look for an amp with much lower powered if I get speakers with limited power handling capacity. 

NO!

Too much power generally isn’t an issue when pairing hi-fi /home theater speakers and amplifiers. It’s the opposite situation—too little power—that can create problems. When an amplifier is driven into clipping (distortion) by being asked to produce more power than it’s capable of delivering, the voice coil of the speaker it’s attached to can overheat and become damaged. That said, an RMS power rating on a speaker doesn’t even begin to tell the whole story. Two other specs, sensitivity and impedance, are much more important in determining how much power a particular speaker requires to deliver sufficient volume levels.

You'll likely damage your hearing before the speakers 

Technically yes, you could damage your speakers with over wattage, but as someone stated, your ears would probably be damaged first. There is more risk with an underpowered amp that starts clipping at high volumes, this will trash your speakers much faster. 

THANK ALL of you for usefully responding to my query.
My overall take-home: an underpowered amp driven to clipping seems more likely to damage a speaker than clean power that controls the linear motor of audio transducers. An amp driven at its upper limit is more likely to clip tops of waves, causing the voice coils to stay in one position just drawing current [may not have said it perfectly]. 
I still have great hearing even after being in a rock band during my 20s [took great care to protect ears during all performances], and we often get out an audiometer to ensure the sound-pressure-level is well under 95dBA for sustained periods. So far, so good! 

There is no such thing as too much power. It is far more common for an underpowered amp to destroy speakers with clipping which can easily overheat fragile voice coils.

High powered systems are always limited unless you like destroying your ears. K horns will easily destroy your ears before they get into trouble. 

Thanks! mijostyn! 
I follow some Audiogon discussions, but this is my first time to submit a query.
Impressed that there are folks out there who as OCD perfectionist regarding good audio as I! 
Based on this experience, I'll likely join some other discussions groups. It's a great community! 
 

Amplifiers can damage loudspeakers with too much sustained high power.  If you treat your loudspeaker's voice coils as if they were a fuse, they will eventually fail.  Use some common sense. 

sometimes these discussions leave me speechless

It really can. I've damaged my speakers with large power!

I’ve always had power amps that far exceeded the power handling capacity of my speakers. Never damaged a speakers. Particularly with solid state amps most speakers benefit from having large excess capacity, yielding more solidity.

As my systems got better the volume of maximum enjoyment went down, until now 65db to 75db is typical… cracking 80 if I am enjoying it really loud..

....nothing like the fragrance of fused voice coils to flip enthusiasm into ennui...

Note that any tube guitar amp from a 5 watt studio amp to a 100 watt whatever will often be used overdriven with distortion into the speakers for DECADES with no harm done. If people are lame enough to drive their delicate little home stereo speakers to the edge with a high powered amp (especially a solid state one) there's little to be done for them.

As pointed out in one of the threads, when the maximum power of an amp is reached, the distortion rises very quickly. It is a "bell" curve rise. The distortion goes from "zero to a hundred" really fast (smallest movement of the volume control), and the distortion created plays havoc with the tweeter/s and midrange speakers.

Not so much with a group like this, but what I saw with the "how loud will it go" crowd was, they "cracked it" and after a while the tweeter went. Five to ten percent of the sound was lost, so they "cranked it" again.  A short time later there was less sound again because the mids were fried.

Woofers pretty much have to be abused with brute over powering or "bottoming" them out with excessive bass and power. I had knuckle heads complain that their speakers were  making a "whip cracking" sound, or a "blatty" sound. As it turns out, they have the loudness button in, bass control cranked to the max, and  the volume control at 3:00 (because that's only 3/4's of the way up, it should be able to do that).

In my experience, less than 5% of the time did speaker repairs result in a woofer failing.

To go along with that, I saw more blown speakers caused by them being under powered, than over powered, and that goes back to how the distortion increases when full volume is reached..

As for the guitar amp being over driven, in most cases you are dealing with a speaker that is basically a woofer. The distortions being generated by the "stomp boxes" are in the mid and upper range frequencies. This is not really taxing or putting the speaker in any danger. 

I have a pair of B&W speakers that have a recommended power of 50 to 300 watts. I'm driving the pair with a 120 watt tube monoblock amp attached to each. Other than having to chase down a ground loop issue (which I solved the other night), this setup is flawless. It may be "underpowered" but sure does not sound like it. I may build two more monoblocks and Bi-amp the speakers, for now, I have no need and it sounds amazing.

@joelepo wrote:

I have a McIntosh 402, rated 400 watts continuous per channel. If I use it to drive a pair of Klipshorns or LaScala [specified to handle 100 watts continuous] or similar high-efficiency speakers, do I risk damage to such speakers?

The La Scala’s are just around or slightly above 100dB’s measured sensitivity, and so would be very loud even with limited power supplied by the McIntosh; practically you likely won’t get to where your speakers are challenge thermally let alone mechanically, whereby the power in reserve will come in handy with loads of headroom (which is a good thing). However, something tells me the La Scala’s thrive on tube-based amps, preferably moderate to higher powered variants, so that might be worth experimenting with.

With inefficient and passively configured speakers in general (and most are), I’d recommend at least double the amp output power of the speaker’s long term max. power handling capacity. Less SPL requirements/shorter listening distance/more lively damped rooms can do with less amp output power.

Efficient and typically passively configured speakers of yore/vintage origins or inspired (with lower to moderate power handling) seem to thrive on and get by with low powered amps, tube-based in particular, whereas more modern and pro segment high efficiency speaker designs with larger voice coils and stiffer suspensions like to be fed by high powered SS amps - they simply come better and more assuredly to life this way, not least actively. Both approaches have their strengths; the former can come across seemingly a bit more lively and with more character, while the latter has the more solid and, to my ears, "neutral" and resolved imprinting. I prefer the latter camp for a variety of reasons, but I can appreciate either approach.

Thanks all for contributing to my education.
I play guitar and 5-string bass and have one Fender Pro tube amp with twin 10" speakers and a Fender SS Bassman with four 10" speakers. Guitar amps and speakers differ from high-fidelity amps and speakers. The former are designed to "produce 'music'" -- so as long as they hold together and generate the sound the musician want, all is OK. In contrast, seems to me that "high fidelity" speakers should not contribute any of their own voice to the sound that comes out. I KNOW... achieving that ideal is far more complicated than that. 

I've been playing electric bass for decades and I have a couple of pro bass amps (15s, 12s, mondo pro sub) and one learns that there's obvious limits on how loud you can play before the speakers get annoyed. Is this too basic? Over 6 maybe? Electric Bass teaches an interesting tone exercise.

Yes, but the speakers will hurt you before you can hurt them.

"we often get out an audiometer to ensure the sound-pressure-level is well under 95dBA for sustained periods."

This would be less than ONE WATT fed to your Klipsch speakers. I think you’re good.

A little historical context:

When Bose 901s were first introduced to the audio world, they had a power rating of 270 watts (If memory serves correctly). They were having incidences of catastrophic driver failure. A quick study revealed that little Pioneer receivers (around 10 WPC true RMS power) were the culprit. These little boxes were, essentially, turning into low amperage DC power supplies at sustained clipping for long periods of time (hours). Bose raised the "recommended" minimum amp power rating to 50 WPC. Problem solved.

@waytoomuchstuff  That is exactly right. Too little power is more likely to do damage than too much, but there are some caveats that most audiophiles are aware off. With high powered systems it is stuff like dropping the tonearm on the record with the volume up. Or switching to a higher gain source with the volume up. 

waytoomuchstuff: old enough to be familiar w the Bose901power issues. 

To mijostyn and others who warn about TOO LOUD sound: We use an audiometer to monitor our listening room and most of our listening is below 70dB; if we are watching an action movie with lots of special effects, we find transient peaks of 100dB or more. A few minutes a day of over 95dB is unlikely to  cause permanent damage.

BTW, the new Apple Watches have an App that monitors SPL and seems to deliver readings pretty close to what I get from our more sophisticated audiometer. 

Doing some quick math here, your Mac and K'horns or LaScalas should hit peaks of over 130 decibels in your room. Should be plenty of dynamic range available on demand.

agree... with your math😁. And will not even approach 130db in our theater. 

About 30 years ago a dealer (who shall remain nameless) in Philadelphia told me that basically, "Too much clean power has never hurt a speaker."  He told me a lot of other things that I suspect would get pushed back on here.

JBL warns about loud levels. See JBL studio monitor technical manual here last page caution section SPL!

Mike

I had same question not long ago. I wrote to Buchardt customer service if I can use for example 800W amplifier (Peachtree Class D) with my speakers (4 Ohms, recommended power 40-200W) and that was the answer:

You can use an amplifier with as many watt's as you wish, as long as you don't turn the volume up higher than the speakers can handle, it is not a problem at all :)
More wattage helps the speakers to perform better when pushing the volume up, so you cannot really get "too many" watts.

Thanks iad for nuancing this discussion!
I'm no longer worried about. having an over-powered amp, as long as it's clean power driving my speakers and as long as I don't drive my hearing to deafness. 

For my latter concern, I'd advise all to monitor ambient listening SPL with audiometer. I keep my general listening between 60- and 70-dBA and listen to music up into the 80s dBA-- dependent on the genre. For home theater, we set to between 70- and 80-dBA for most dialogue, but expect transient peaks into and beyond 90dBA. 

@joelepo glad to hear you are happy with your setup now

I never mesaured it, I should try

@joelepo 

Exactly right- don’t worry unless you really crank it up to hearing injuring levels and beyond.  Congrats on saving your hearing.  

      +1s...to all that mentioned more speakers being damaged by underpowered amps, driven into distortion/clipping, taking out tweeters and: then mids.

       When I had my shoppe, in Winter Park, Florida; that's what I saw the most, having four major colleges, so close by.     Especially: the beginning of the week, after their parties.

        I stocked a variety of Zener diodes and heat sinks, that I made limiters with, to protect 'em and they'd still melt the adhesives (used as witness), at which point: bigger amps were provided.

        Typically: the only woofers that came in and needed reconing or replacement, were from the multitude of musicians, live music venues and the Navy base's E-Club disco (4 Cerwin-Vega 15" 3 ways and two Flame Linear 700s), in the Orlando area.

         I was one of Central Florida's  warranty stations, for Cerwin-Vega, Altec-Lansing, Gollehon, EV and JBL's Pro lines and could offer 24 hour service, for most of those. 

                            Pros like that.  Keeps 'em in business, making music.

          I'd still be there, enjoying that aspect of the hobby, but for a stinking sinkhole, opening up twenty feet from my property. 

                                                 Oh well!    ¯\_(ツ)_/¯

                                                    Happy listening!

If you crank up the volume beyond the speaker’s capababilities for an extended period, then you’ll likely blow the speaker. However, typically it’s an underpowered amp that goes into clipping that will destroy the speaker. More power is better, but must be used judiciously.

Rb61 agree. +1. My experience with my Tekton speakers and my Tsakadiris 150 w mono? I got involved so much on the music playing. I crank the volume beyond the speakers limit , I blew the tweeter.So be careful.

Don’t you have a preamp?

Just don’t turn it up.

A general rule of thumb we see in service of loudspeakers 

too much power sent to a speaker cooks woofers (from being too loud, beyond the dynamics of the speaker)

underpowered usually cooks tweeters as the amp runs out of power and begins clipping ( clipped output = square waves = impossible for a speaker to follow a square wave precisely so it overheats trying to )

Brad

Not a good match.  Don’t do it. 

I spoke to a manufacturer who said that excess power is a big threat to speakers more so than high frequency components of distortion burning out drivers.  I’ve seen too many examples of accidents with high powered amps sending damaging pulses to speakers (someone accidentally pulling an interconnect, a power failure where flickering power results in a loud thump, etc.).  I don’t get why people play their systems so loudly that they would burn out drivers from distortion—things will sound bad long before that point is reached.

If only a tweeter is blown, that could be from an amp heavily distorting because distortion is primarily high frequencies.  But, other drivers are not getting those higher frequencies so if they blow, it is because too much power was delivered, regardless of distortion.  

I think it is safer to stay on the lower end of a manufacturer’s recommended power requirement and then don’t listen at levels where distortion is evident.

• It’s power that kills drivers
• High power amps are safe if you can fully control their output - this means know your volume knob’s "levels", and adopt patterns that prevent transient spikes - e.g. power on/off in the right sequence, mute when cueing a stylus, control LF feedback and woofer "flapping" if you have a turntable (through proper isolation) etc.
• Low power amps are safe if you keep them away from clipping conditions. At some point, power output may be low enough that even clipping doesn’t harm your tweeters - but I wouldn’t go looking to experiment on that.
• Tube amps are bandwidth limited at higher power levels, which causes their clipping wave to be *slightly* rounded compared to SS. But I can confirm, a typical tube amp’s hard-clipping still sounds like sh*t and can damage your tweeters - don’t rely on tube amps being much "safer" here.
• High efficiency speakers aren’t always correlated to higher or lower power handling. You can usually play louder safely with high efficiency. That’s why aficionados of loud sessions like me love them :)
• Tweeters typically have much lower power handling levels than woofers in the same speaker - up to an order of magnitude less. This is normally OK because like "pink noise", musical content carries much less energy above 4KHz (etc) than below - "equal energy per octave".
• When you force an amp into clipping, not only does it carry up to 2x the amount of continuous power versus unclipped (basic math - area under a sine curve versus a line), it also "rewrites" the signal to have a higher proportion of high frequency content. This is especially true for "peak" power. This is why it puts tweeters at risk - they’re not designed to take as much power as the woofers in the same speaker, so they’re sitting ducks under clipping conditions.
• Woofers are more at risk from poorly isolated turntable setups. Poor isolation and uncontrolled resonances can cause low frequency feedback. In the subsonic range, this is seen as woofer "flapping" - =-- besides power from the huge amplitude, it can cause woofers to hit their excursion limits and damage the voice coil. In the audible range 20 - 120Hz, LF feedback may be confused for ground hum at lower levels, and can even cause runaway feedback at higher levels. LF feedback can even get so bad it pushes your amp into clipping which then "suddenly" generates a HF spike (a very, very loud POP) that can kill your tweeters!

Mulveling, that is a terrific summary of the issue.

Remember this: "No amount of power will damage speakers if you use your ears and common sense to know when the recording comes into its own at a particular power level. I used a 400-watt power amp with my Electrostatic Quad speakers with absolutely no issues.

@phillyb

From the number of damaged speakers we get in for service, I dont think your idea works in practice. And Im lost when you say "know when a recording comes into its own at a particualr power level". I assume you mean that you should be able to hear when it begins to distort? Gosh I wish you were right becasue if this were true I would never get a blown speaker/driver in for service!

I’m also not clear on this idea that Recordings have a favored or preferred power level (assume you mean playback SPL). Playback systems systems do have a maximum power level, but Im not sure they have a preferred or even minimum playback SPL we could all agree on.  QUADS were notorius for having a very limited max power level and limited dynamic range so perhaps your hearing is oriented around this?  (Billy Woodman from ATC loved loved loved quads for their extreme definition).

Recording systems also have "preferred" input gain settings as well but even this is up for debate in practice. There is a well known story of the Beatles arguing with the Abbey Road Engineers that a distorted input signal (exceeding the preferred input gain of the system) was NOT a mistake.

Provided a high power amp source with multiple times the output of a quality speaker’s power handling capacity, it would usually take quite the beating for longer durations for the speaker to actually fail thermally and/or mechanically. Before that happens there’d be sonic implications going from dulled dynamics to outright strain and severe mechanical distortion, and if in the meantime one doesn’t identify these signals as warning signs, well, then I’d seriously question that individual’s ability to assess sound in a fairly skilled manner. Misuse of one thing (incl. what can lead to  all sorts of accidents, some of which are already mentioned in this thread), but unless we’re partying all night with our brains shot without any care in the world for the equipment used (not to mention our ears), most of us around here under more controlled and sober conditions should be able to properly assess when it’s time to ease off on the volume control and call it a day.

Really, it’s not that complicated. How many amps are there in the kW’s range? Buy whatever you like that fits your sonic and SPL needs, and if it means going with an amp that has more power than the speakers rated power handling, don’t worry. On the contrary, I’d worry less, because all things being more or less equal and provided again some common sense use, that amp should perform more effortlessly and with lower distortion at a given, higher SPL.