Originally posted by: leibler
Holy crap - reading this thread made me want to throw my computer out the window.
uke:
<STRONG><EM>FREE KNOWLEDGE FOR THE BATTLE FOLLOWS!</EM></STRONG>
When it comes down to it, there are only two things that can kill speakers - heat & overexcursion. Not power, not "clipping" or some other means. Some of these conditions may lead to heat or overexcursion, but they do not directly cause failure.
<STRONG>Heat</STRONG>
Heat kills speakers by simply melting it from the inside. An accurately rated 1000W rms speaker dissipates 1000W of heat all day long so long as it is moving. That's how manufacturers determine power ratings. Remember from science that energy is never created or destroyed, it just changes form? Electrical energy turns into mechanical energy at the voice coil. But if you exceed that 1000W input power, where does that extra energy go? It turns to heat - the voice coils begin to warp, magnets may melt and glue can separate causing failure.
<STRONG>Overexcursion</STRONG>
Overexcursion occurs when a speakers is prompted to move farther than it is mechanically capable of. For example, if 1000W rms moves a speaker 2 inches from resting position and that speaker is designed to move a maximum of 1 inch, it will likely be damaged. Either the surround will separate, the voice coil will break or become otherwise compromised, the speaker cone will separate from the spider, or any combination of all of these. 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.
<STRONG>Distortion</STRONG>
Distortion is output that varies from the input to the amplifier in some way other than power amplification. This may include added noise, pops, signal degradation, hissing, alternator noise/sine waves, etc.
<STRONG>Clipping</STRONG>
God, I love this one. Many people have no idea what clipping is. Some people think clipping is a sound you can actually hear or a special signal or level of volume/gain. Clipping is an event that occurs when an amplifier is requested by pre-amp signals to produce more output voltage than it has the capability to do.
Take my JL Audio 500/1 monoblock sub. 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= 500W; R = 4 ohms
P = I * V; since V = IR
P = I^2 R
500W = I^2 * 4
I^2 = 125
I = 11.18 amps
Since V = I*R
V = 11.18 * 4 = 44.72 volts
When the amplifier gets to 44.72 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 44.72 volts at one or many frequencies, but that is the maximum output voltage it is capable of - the signal output reaches a maximum ceiling.
If you look at a sine wave (your amplifier's output is a sine wave) it goes up and down smoothly. Once you reach the threshold of tolerance for the amp, the top and bottom of the wave quit being smooth curves and look on the oscilloscope as if they've been "clipped" off. The speaker and amplifier don't stop moving because the amp is "clipped." It's just that having a volume or gain knob simply does no more good for the strongest frequency - it is stopped at a maximum, while the other information continues to be amplified (increase).
Keep in mind, any amplifier that is capable of putting out 1000W rms is capable of putting out 2000W max (a 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 car audio gurus tell you that clipping kills speakers is because most people draw a parallel between speaker value and attaining the maximum heat or excursion capabilities of the speakers when that's simply not the case.
Physics, ya'll... and math.
It boils down to these simple steps:
Design your system well BEFORE purchasing any components.
Make sure components are properly matched to each other.
Make sure components are properly installed.
Make sure your system is tuned and tweaked responsibly and properly.
The key is in balance and knowledge.
BTW, I'm a nationally certified MECP First Class car audio installer and did this for a living before I got in the Army. I used to have this conversation all the time with customers. I love watching people get so excited and angry over this subject. Sometimes I even start these arguments for fun...
:evil:
