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full Volume on power Amp?

#25
bongomania said:
...With the caveat that only sending too much power into the speakers can blow them. .
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Hoping you're being sarcastic...

As someone else who does this for a living (audio, not playing bass...), I can assure you that it's much easier to blow a speaker with too little power than too much. Amps, at least solid state amps, clip in the form of DC, which is the enemy of speakers. A bigger amp can overheat a voice coil, but it takes a while. Clipping from a too-small amp doesn't take very long at all, and is very effective.

Otherwise, I agree with Bob from QSC on all points concerning volume control settings.
 
#26
Alanthecowboy said:
Hoping you're being sarcastic...

As someone else who does this for a living (audio, not playing bass...), I can assure you that it's much easier to blow a speaker with too little power than too much. Amps, at least solid state amps, clip in the form of DC, which is the enemy of speakers. A bigger amp can overheat a voice coil, but it takes a while. Clipping from a too-small amp doesn't take very long at all, and is very effective.

Otherwise, I agree with Bob from QSC on all points concerning volume control settings.
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This would be very much the minority opinion amongst the professionals here, who regard underpowering to be a myth. If you're sending spikes with a clipping amp, that would be overpowering, and it would still need to be powerful enough to produce those spikes. I know my speakers survive the abuse of turning off my amp overnight, despite spending all that time being underpowered.
 
#27
GrowlerBox said:
This would be very much the minority opinion amongst the professionals here, who regard underpowering to be a myth. If you're sending spikes with a clipping amp, that would be overpowering, and it would still need to be powerful enough to produce those spikes. I know my speakers survive the abuse of turning off my amp overnight, despite spending all that time being underpowered.
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In the HiFi and PA industry from whence I come, there's no debate on the matter. It takes real effort to blow a speaker with a big amp. I've driven a pair of 900 Watt monoblocks into a pair of 5 inch woofers for a few drunken evenings with no ill effects, but if I hook my old NAD 20 wpc integrated up to the same speakers, they're toast. I would welcome some debate with the other professionals.
 
#28
Alanthecowboy said:
As someone else who does this for a living (audio, not playing bass...), I can assure you that it's much easier to blow a speaker with too little power than too much. Amps, at least solid state amps, clip in the form of DC, which is the enemy of speakers. A bigger amp can overheat a voice coil, but it takes a while. Clipping from a too-small amp doesn't take very long at all, and is very effective.
Click to expand...

No, you won't blow a loudspeaker from too little power. However, by clipping an amp you make it put out power that exceeds its rating. That could overpower a loudspeaker whose thermal capacity is too low for that much power; you could also blow out the loudspeaker without clipping by using a power amp with a higher power rating.

Clipping is not DC. The enemy of a loudspeaker is too much power, whether it's AC or DC (it's almost always AC unless the amp is defective), whether the amp is clipping or not.
 
#29
Alanthecowboy said:
In the HiFi and PA industry from whence I come, there's no debate on the matter. It takes real effort to blow a speaker with a big amp. I've driven a pair of 900 Watt monoblocks into a pair of 5 inch woofers for a few drunken evenings with no ill effects, but if I hook my old NAD 20 wpc integrated up to the same speakers, they're toast. I would welcome some debate with the other professionals.
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While you're right that there's no debate, it's not in favor of your position. Two things destroy loudspeakers: excessive power (which causes excessive heat) and overexcursion. Tiny loudspeakers that could be toasted by a 20W/ch amp could indeed be run safely by 900W amps if you only make them put out less than what it would take to blow the loudspeakers.
 
#30
Bob Lee (QSC) said:
No, you won't blow a loudspeaker from too little power. However, by clipping an amp you make it put out power that exceeds its rating. That could overpower a loudspeaker whose thermal capacity is too low for that much power; you could also blow out the loudspeaker without clipping by using a power amp with a higher power rating.

Clipping is not DC. The enemy of a loudspeaker is too much power, whether it's AC or DC (it's almost always AC unless the amp is defective), whether the amp is clipping or not.
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I was hoping you'd weigh in on this, Bob. The RMS power of clipped signal is indeed higher than a clean sine wave of the same peak to peak voltage, but not enough to account for the ease with which folks can toast otherwise hardy speakers with otherwise lightweight amps.

Clipping isn't DC? I beg to differ. It is surely not AC, at least when considered in the small time frame necessary to blow a speaker.

Much of my argument may be anecdotal, but it comes from real experience, and I do spend a good part of my workday dealing with this.

My concession would be to admit that some amp manufacturers do provide protection for this sort of thing, such as Peavey's DDT (although I don't trust it). In cases where an amp is not permitted by design to send dangerous signals to a speaker, you would indeed need to overheat the voice coil (or bottom out the voice coil to the point of mechanical damage) to blow a speaker.
 
#33
Technically, there's no such thing as "RMS" power. RMS--root mean square--is a method for measuring AC voltage or current. They yield "average power." So you are correct that the average power in a clipped signal of a certain peak voltage is greater than that of a clean sine signal of the same peak voltage. That's because its RMS voltage is higher. Too much power kills loudspeaker by driving the voice coil temperature too high; there is no danger inherent in any particular signal waveform.

A clipped signal is AC, not DC.
 

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