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overpower or underpower, a hypothetical..

#102
Yeah, I had second thoughts about the word "lies", but it's been so beaten to death in this thread and in this forum that at this point for anyone to recite that same old crap needs a stronger word than "misinformation". Maybe I should have said "heinous old wives' tales". :)
 
#104
vail_bass said:
brilliant response, were you drooling at the time, too?
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vail, you know i greatly respect you, bro. but they're right. if square waves alone fried speakers, nobody could run distortion or synths through them, and my b-15n, which gives you about 60w total peak power when turned up all the way, would fry my 810. and yes, i've done that before ;)

if a clip fries a speaker, it's because it overpowered the speaker. mere clipping won't get it done unless it's more than the speaker can handle.
 
#107
Growly Lytes said:
How is it possible to blow a woofer rated for 300 watts when I'm only using a 100 watt amp to push it?

Underpowering a speaker is likely to damage the voice coil due to the excess heat created by distortion. This distortion, called clipping, is created when the amp is not able to supply the power demand when the volume is turned up. If you turn the volume up very high without the power to back it up, you'll end up clipping the signal coming out of the amp. The speaker will try to reproduce this clipped signal, and if played under these circumstances for any length of time, the speaker will not last very long.

There is a mis-conception that if you're not giving the speaker as much power as it can handle you won't blow it, but that simply is not the case. The only way to really address this problem is to replace your speaker for one with a lower power rating, and a higher SPL rating, or replace your amp with one that better matches the speaker's power handling capability. An alternative to replacing the equipment is to simply keep your volume turned down!
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Not one bit of that is true, and why it's not true has been documented here on a more or less weekly basis since this unfortunate thread first appeared.
When giving advise to others a pre-requisite is knowing what you're talking about, and not blindly quoting rumor from unaccredited sources.
 
#109
Growly Lytes said:
Underpowering a speaker is likely to damage the voice coil due to the excess heat created by distortion. This distortion, called clipping, is created when the amp is not able to supply the power demand when the volume is turned up.
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No, that's wrong also.

Audio signals, whether distorted or clean, produce heat in loudspeakers. The loudspeakers don't know what part of the signal is clean and what part is distorted, but >90% of the signal that you put into them gets converted to waste heat instead of acoustical energy.

Too much power causes overheating.

Too little power cannot cause overheating, unless you've discovered a way to create energy from nothing. If you do, though, you could probably win a Nobel Prize.

An amp driven to clipping is putting out more power than the amount stated in its rating. Really objectionable clipping might result in 30–50% excess power. Theoretically, if the signal was so clipped that it formed an actual square wave, it would put out 2× its rated maximum, but that would be so extreme as to be almost impossible.
 
#110
Would you guys say that you can hear the 'danger signs' before there is an issue with blowing a speaker? If you are, for example, running a 600 watt head into a 1000 watt cab and the tone is powerful, undistorted and pleasant, can you be mostly assured that there is no danger to damaging the speakers?

I know some of you guys are saying it is beating a dead horse, but it is helpful to read through the thread, hear all the 'myths', and have them debunked/proven. For an engineer, a thread like this must be tiresome---but to an average gigging musician, there is alot of good info here.
 
#111
Bob Lee (QSC) said:
No, that's wrong also.

Audio signals, whether distorted or clean, produce heat in loudspeakers. The loudspeakers don't know what part of the signal is clean and what part is distorted, but >90% of the signal that you put into them gets converted to waste heat instead of acoustical energy.

Too much power causes overheating.

Too little power cannot cause overheating, unless you've discovered a way to create energy from nothing. If you do, though, you could probably win a Nobel Prize.

An amp driven to clipping is putting out more power than the amount stated in its rating. Really objectionable clipping might result in 30–50% excess power. Theoretically, if the signal was so clipped that it formed an actual square wave, it would put out 2× its rated maximum, but that would be so extreme as to be almost impossible.
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Once again....HERE'S the truth.

Check please....:atoz:

Any chance of ending on a high note?
 
#114
Overpowering by 10-25 percent is not an issue. The speakers are rated by CONSTANT heat dissipation/thermal handling, and you have a few things that help.

One is a properly designed enclosure, which prevents xmax(maximum speaker excursion) from being reached.

Another is that your bass doesn't play a steady note, held for an entire set.

You can exceed thermal handling for short bursts, all nite long. I put a subharmonic synth through an 18 cab, and eq'd, with a 4x12 on the other side of an ampeg 1500 watter, and the roughly 680 watts the 18 got was well over the 450 it was rated for. Also, the 4x12 was rated at 400 total. It was seeing the same 680.

Even with a dbx120a on the 18, never a prob.

Also, A/C power supply to the amps is never as high as it is in the nice little laboratory where output is tested....Theres a proportional reduction of output....

That said, I generally shoot for 95-115 percent of cab power handling....Guitar, bass, proaudio, home/car audio....etc.
 
#116
@ tallboybass - Too little power - CAN cause issues. The square top of its wave, has LONGER duration than the little tip of a sine that is not clipped. If it is at thermal handling for lengthy duration, (it would have to be just SLIGHTLY underpowered) then it can cause excessive heat in the coil of a driver.

This would only be obtainable in a preamp/power amp combo where the pre could clip the power amp, or the sensitivity of the power amp could be manually adjusted so that the input waveform is modified.

And yes, it is rare.
 
#120
dubcut said:
@ tallboybass - Too little power - CAN cause issues. The square top of its wave, has LONGER duration than the little tip of a sine that is not clipped. If it is at thermal handling for lengthy duration, (it would have to be just SLIGHTLY underpowered) then it can cause excessive heat in the coil of a driver.

This would only be obtainable in a preamp/power amp combo where the pre could clip the power amp, or the sensitivity of the power amp could be manually adjusted so that the input waveform is modified.

And yes, it is rare.
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let me guess...you read only the first post and answered without reading where several engineers already debunked this nonsense IN THIS THREAD!

a little advice...read more than just the first post before you answer.
 

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