Joined: Nov 16, 2001
Posts: 2053
From: Mpls, MN

------------------------ 
Speakers do not know the difference between music, distortion, clipped signal, harmonics, sub harmonics, 3rd & 5th order harmonics--they just TRY to reproduce them. The operative word is TRY. 

If you give a 1" dome tweeter 50 Watts of 40Hz music, you'll surely kill it. Why? Read the below link. 

http://www.rane.com/pdf/note128.pdf

Will Distortion and/or Clipping kill speakers? Read the above link. 

The link may take time to load, but after reading this, you should have a good idea.

Joined: Nov 16, 2001
Posts: 2053
From: Mpls, MN

"I’m not sure I understand completely. I would say the reason the tweeter would blow would be over excursion. It can't move enough to produce a 40 Hz sine wave. When you say speaker in that post do you mean any driver (i.e. subs)? I understand it as you said up to a point, a sub tries to produce whatever is thrown at them whether music, clipping or whatever signals, but it just can't produce too much clipping without damaging. I know that amps clip all the time but once it gets to a certain level does it not blow then? Could you explain it a little more, just about clipping on a sub and what actually blows a sub (besides you) then the link you posted if its not clipping and distortion and a dirty signal?" 
__________________________________________________ 
Let's take into consideration a Rock band's guitar amplifier. What is the first thing they usually do? They turn up the pre-gain setting in order to achieve a particular level of distortion. In fact, they may be attaining 100% clipped signal (distortion) right? Why then doesn't their speaker kill during a 2-hour concert? Why did Aerosmith use the same guitar amps for several years? 
__________________________________________________ 

Speakers are killed by 2 things (well 3 if you count idiots, weather, and time--actually, that's 6) 

Heat & Overexcursion. 

Heat kills speakers by simply melting it from the inside. A 1000W rms speaker (if accurately rated) will dissipate 1000W of heat all day long so long as it is moving. If you exceed that 1000W input power, the voice coils will begin to warp, and the glue may separate causing failure. 

Overexcursion occurs when a speakers is amplified to move farther than it is mechanically capable of. For example, if 1000W rms moves a speaker 2 inches, and that speaker is designed to move a maximum of 1 inch, it will likely fail. Either the surround will separate, the voice coil will break, the speaker cone will separate from the spider, or ALL OF THE ABOVE. This is why both selecting an amplifier and a BOX design is crucial. Oversizing a box will allow the speaker to move farther than intended with rated power. 

__________________________________________________ 
DISTORTION? 

Distortion is output that does not match what was input to the amplifier. In Aerosmith's case, without distortion, they'd sound like Michael Bolton or Kenny G--pure sound, no frazzled speaker movements. 

Speakers are passive products. They don't know the difference between intended signal and noise. How could they? Speakers basically move in one direction, then quickly back in the other. 
__________________________________________________ 
CLIPPING? 

Clipping occurs when an amplifier is requested (by pre amp signal) to produce more output voltage than it has the capability to do so. 

EX: A RF 800.2 amp ~1000W @ 4 ohms mono. 

What is the Max voltage that amplifier is capable of producing @ 4 ohms? 

P = I V where P= power, I= current, V = Voltage 

V = I R where R= resistance (impedance) 

P= 1000W; R = 4 ohms 

P = I * V; since V = IR 
P = I^2 R 
1000W = I^2 * 4 
I^2 = 250 
I = 15.81 amps 

Since V = I*R 
V = 15.81 * 4 = 63.25 volts 
__________________________________________________ 
ENOUGH MATH!!!!!!!! 

When the amplifier gets to 63.25 volts output (regardless of 4, 2 or 1 ohm output) that amplifier reaches its maximum voltage. At that point, any request for a higher voltage is just DENIED!!! The amplifier may continue to produce 63.25 volts at one or many frequencies, but that is the maximum output voltage it is capable of. 

The amplifier isn't capable of DC output, just that the signal output reaches a maximum ceiling. Diagrams of square waves; whereas, the tops & bottoms of waves being clipped off are accurate for just that. They are not to be interpreted as indicative of amplifier frequency movement. The speaker and amplifier don't discontinue to move because the amp is clipped, only the output does not increase even when you turn up the volume. The strongest frequency is stopped at a maximum, while the other information continues to be amplified. 

Keep in mind, any amplifier that is capable of putting out 1000W rms is capable of putting out 2000W max (fully clipped signal). In the above case, where your speaker is capable of handling 1000W rms, it won't survive 2000W continuously, and will melt should you give it 2000W. 

The reason most stores and alleged gurus tell you that clipping kills speakers is because most people coincide speaker value and attaining the maximum heat or excursion capabilities of the speakers. That's what the Rane publication shows.