500Watt Speakers On A 80Watt Receiver

[annunaki]

However, I don't think you're factoring in the effect of harmonics on the tweeter when the amp reaches a high percentage of distortion. If the speaker can't reproduce it, it turns to heat unless the impedance is extremely high in that range. Ferro-fluid does a great job of saving speakers but it's not infallible. As I posted before, I have seen many drivers go because of low power amps and receivers. Most denied how it happened but eventually, all admitted that they cranked the heck out of it for a long time.

I am well aware that there is a lot of harmonic information that occurs during clipping. However, if the power handling of the tweeter is exceeded, clipped or not, for enough period of time, it will fail.

If a tweeter's true rms power handling is 100 watts rms and a 45 watt amplifier is fully clipped (90 watts), it should not fail as it can dissipate the heat generated accordingly.

Speakers reproduce what is fed into them, they do not know, or care if the signal is clipped or not (obviously since they are not alive nor have a conscience ). The only thing that matters with a speaker (on this front) is whether or not they can handle the heat related with a given input power level without power compression.

 

[highfigh]

There is much you need to learn about how much the marketing department exaggerates what an engineering department does. There is a lot of irresponsibility in the market place, especially when it comes to power ratings whether it be speakers or amplifiers.

You're telling me that I need to learn about marketing companies but you don't know me, right?

I've been in the consumer audio business for 30 years. The amount of BS the manufacturers have spewed has numbed me to its effects. Most of the time, I don't even bother reading spec sheets for exactly the reasons you posted. I probably didn't notice that I forgot to include 'should' when I referred to them rating for long-term but in their specs, they often do, regardless of whether it's accurate or not. Why nobody nails them for falsely making claims, I don't know. Do you know anyone who has tested equipment against the ratings and found them to be wrong?

Thanks for enlightening me, though.

 

[gixxerific]

Headroom! No clipping problem solved.

 

[annunaki]

You're telling me that I need to learn about marketing companies but you don't know me, right?

I've been in the consumer audio business for 30 years. The amount of BS the manufacturers have spewed has numbed me to its effects. Most of the time, I don't even bother reading spec sheets for exactly the reasons you posted. I probably didn't notice that I forgot to include 'should' when I referred to them rating for long-term but in their specs, they often do, regardless of whether it's accurate or not. Why nobody nails them for falsely making claims, I don't know. Do you know anyone who has tested equipment against the ratings and found them to be wrong?

Thanks for enlightening me, though.

Sorry for the sore spot. It was not a personal attack on you, sir. No need to be too serious.

 

[highfigh]

Sorry for the sore spot. It was not a personal attack on you, sir. No need to be too serious.

No problem. Thanks.

 

[gixxerific]

Wait a min are those numbers the Manufactures gives really mean something or not? I thought they were numbers the pulled out of a hat most of the time.

 

[highfigh]

Wait a min are those numbers the Manufactures gives really mean something or not? I thought they were numbers the pulled out of a hat most of the time.

Could be a hat, their pocket, a small satchel, a place that never sees sunlight, etc. S.W.A.G. Method comes to mind. It's like rating an amp as 200 Sony Watts, 200W JBF (Just Before Fire) or 200W WLS (When Lightning Strikes). 'If it sounds or smells bad, turn it down."

I worked with a guy who would have customers ask if a little cheap bookshelf speaker would handle 150W. He'd say, "150 Watts? Sure, they'll handle 150 Watts. Once.".

 

[annunaki]

Could be a hat, their pocket, a small satchel, a place that never sees sunlight, etc. S.W.A.G. Method comes to mind. It's like rating an amp as 200 Sony Watts, 200W JBF (Just Before Fire) or 200W WLS (When Lightning Strikes). 'If it sounds or smells bad, turn it down."

I worked with a guy who would have customers ask if a little cheap bookshelf speaker would handle 150W. He'd say, "150 Watts? Sure, they'll handle 150 Watts. Once.".

I did not realize you were a fellow Wisconsinite!

Cheers to you my friend.

 

[highfigh]

I did not realize you were a fellow Wisconsinite!

Cheers to you my friend.

I figured it was about time I filled in more of my profile.

Cheese to you, sir!

 

[highfigh]

I don't want to belabor the point but from the article '10 Things about Audio Amplifiers You've Always Wanted to Know', the last paragraph states :

"10. How Do Small, Low-Powered Amplifiers Put Speakers at Risk?
Initially, it seems contradictory—how could a low-powered amplifier burn out speakers, when amplifiers of 200 or 400 watts per channel would seem to put speakers at much greater risk? The reason is that a small amplifier of 10 or 20 watts per channel can easily be driven into distortion and “clipping” with even moderately loud playback and dynamic peaks in loudness. The clipping cuts off the waveform and turns the output signal into an almost pure constant DC signal, which can quickly cause the fine wires in the speaker’s voice coils to overheat and melt. A large amplifier outputs clean power to the speakers –distortion-free AC audio signals—that the speaker voice coils will accept on a momentary basis without damage."

 

[annunaki]

I don't want to belabor the point but from the article '10 Things about Audio Amplifiers You've Always Wanted to Know', the last paragraph states :

"10. How Do Small, Low-Powered Amplifiers Put Speakers at Risk?
Initially, it seems contradictory—how could a low-powered amplifier burn out speakers, when amplifiers of 200 or 400 watts per channel would seem to put speakers at much greater risk? The reason is that a small amplifier of 10 or 20 watts per channel can easily be driven into distortion and “clipping” with even moderately loud playback and dynamic peaks in loudness. The clipping cuts off the waveform and turns the output signal into an almost pure constant DC signal, which can quickly cause the fine wires in the speaker’s voice coils to overheat and melt. A large amplifier outputs clean power to the speakers –distortion-free AC audio signals—that the speaker voice coils will accept on a momentary basis without damage."

Amplifiers, especially modern day ones, do not output DC even under full clipping. Poorly designed amplifiers may allow this, but even the cheap ones in the market today will avoid this. Just because the squared or clipped waveform on an oscilliscope looks similar to DC does not mean that the amplifier is outputting a DC signal.

If it were outputting DC, the woofer cone would just stick straight out or suck in with little or no audio output.

Could you provide the link to the full article. I would like to check it out.

 

[highfigh]

Amplifiers, especially modern day ones, do not output DC even under full clipping. Poorly designed amplifiers may allow this, but even the cheap ones in the market today will avoid this. Just because the squared or clipped waveform on an oscilliscope looks similar to DC does not mean that the amplifier is outputting a DC signal.

If it were outputting DC, the woofer cone would just stick straight out or suck in with little or no audio output.

Could you provide the link to the full article. I would like to check it out.

The point is that when a low powered amp clips hard, at high frequencies, if you want to think in terms of a duty cycle, the signal is so close to being square wave, that it ends up having a very similar effect to DC. The caps still want to block a continuous DC voltage but since the signal is still AC (non-sinusoidal, complex) and can pass through. Woofers obviously aren't affected by this as much because the harmonics are too high and the inductance of the VC and crossover filter them out.

The article is on the Audioholics home page. I'll attach a link.

http://www.audioholics.com/education/amplifier-technology/10-things-about-audio-amplifiers

Also, even though we like our nice expensive/higher quality gear, there's only a thin band of really great and really bad equipment, with all of the rest in-between. On the lower mid-range of quality, there's a lot of iffy stuff that really would rather not be driven hard and when it is, any chance of it sounding good or living long are pretty much out the window. If you get a chance to use some of this equipment, put a pair of ear plugs in and crank it up to the point of clipping, then watch as the woofer cone drifts in and out. The amp won't have much control of the speaker and this is when speaker damage is very likely to occur. I did car audio for too long and have seen speakers look like they exploded because the system was run well outside of any safe zone.

 

[PENG]

The point is that when a low powered amp clips hard, at high frequencies, if you want to think in terms of a duty cycle, the signal is so close to being square wave, that it ends up having a very similar effect to DC. The caps still want to block a continuous DC voltage but since the signal is still AC (non-sinusoidal, complex) and can pass through. Woofers obviously aren't affected by this as much because the harmonics are too high and the inductance of the VC and crossover filter them out.

The article is on the Audioholics home page. I'll attach a link.

http://www.audioholics.com/education/amplifier-technology/10-things-about-audio-amplifiers

Also, even though we like our nice expensive/higher quality gear, there's only a thin band of really great and really bad equipment, with all of the rest in-between. On the lower mid-range of quality, there's a lot of iffy stuff that really would rather not be driven hard and when it is, any chance of it sounding good or living long are pretty much out the window. If you get a chance to use some of this equipment, put a pair of ear plugs in and crank it up to the point of clipping, then watch as the woofer cone drifts in and out. The amp won't have much control of the speaker and this is when speaker damage is very likely to occur. I did car audio for too long and have seen speakers look like they exploded because the system was run well outside of any safe zone.

That little 10 to 20W (cited in the linked article) amp is not going to melt the VC of a speaker that can handle say, 200 rms. Its little power supply transformer's secondary winding won't be able to sustain much voltage under severe overload condition. If you write to Allan Lofft and ask him for more details, he may (just an educated guess) tell you that he exaggerated the effect of the clipped waveform to make a point.

 

[highfigh]

That little 10 to 20W (cited in the linked article) amp is not going to melt the VC of a speaker that can handle say, 200 rms. Its little power supply transformer's secondary winding won't be able to sustain much voltage under severe overload condition. If you write to Allan Lofft and ask him for more details, he may (just an educated guess) tell you that he exaggerated the effect of the clipped waveform to make a point.

I don't know about that amp but I have seen an awful lot of blown speakers that were connected to low or medium powered amps. Granted, I haven't seen this much lately but I would never say it's impossible.

I think someone will need to sacrifice some equipment, so we'll have some definitive answers.