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Jebol disebabkan hanya 2: Thermal failure dan Mechanical failure.

Jebol karena faktor thermal/panas
The causes for thermal failure are :
- too much input power
- signals outside the speaker bandpass (radio frequency, subsonic frequencies, deep bass). Energy not to converted to sound ends up as heat
- amplifier clip, the most common cause of thermal failure
- direct current (DC) at the amplifier output, although this is uncommon in today's amplifiers
- excessive equalization, mostly high frequencies, since these frequencies exhibit low transducer efficiency and generate lots of heat

To prevent thermal failure, avoid amplifier clip and ensure that the speaker is only receiving frequencies within its bandpass, using high-pass and low-pass filters to limit the frequency content being fed to the speaker.

Jebol karena faktor mekanis
The causes for mechanical failure are always linked to excessive diaphragm (cone) movement. The speaker shows greater excursion (backward and forward movement) the lower the frequency. Hence a signal low enough in frequency and large enough in level may cause the voice coil to exit the gap, resulting in the coil rubbing, and possible ending up shorting or opening. The worst case scenario happens when the coil former hits the bottom pole piece ("bottoms out") and gets deformed.

To prevent mechanical failure, avoid using signals below a speaker's bandpass, and use an amplifier of the correct power output.

Power Rating
Don't assume that just because your amp isn't rated for more power than your drivers that you can't blow them. Transient pulses of less than a millisecond can toast a driver just as easily as long term overpowering. An amp with a nominal 300 watt rating can provide short duration power bursts at least 6dB higher, and that takes you up to 1200 watts. A well made amp can have 10dB of dynamic headroom over and above the nominal rating, and in the case of a 300 watt amp that gets you up to 3000 watts. The only way to protect your drivers from both overexcursion and long term heat build up is to limit the signal level going into the power amps with a limiter, which allows normal signal levels to pass unaltered but keeps high level transients out.

Don't assume that just because your driver is rated for, say, 800 watts that it's OK to drive it with 800 watts. If you do this can be the result:


Clipping

Clipping means that the tops of the signal are “clipped off” or “flat-topped” when the signal level is exceeding the maximum capability of the power amplifier or some other piece of equipment in the system.

During the times when a signal is flat-topped, loudspeaker cones are not being “instructed” to move as it is receiving essentially a DC signal. This means all power goes into heating up their voice coils instead of producing sound. In other words, during the times the signal is flat-topped a loudspeaker is 100 percent efficient at converting power into heat.

Ironically, the more efficient the driver, the worse the problem. A horn tweeter (~25 percent efficient) normally converts 75 percent of its input power to heat. During clipping it must convert 25 percent more power to heat.

A cone woofer (~3 percent efficiency) normally converts 97 percent of its input power to heat. During clipping, it has to convert a mere 3 percent more to heat. Now you know why tweeters burn out much more easily.

Thermal Inertia
A hidden consequence of clipping is that, while high frequency drivers are more efficient in converting electrical power to sound, they have less mass than low frequency drivers.

Mass translates into thermal inertia. The higher the thermal inertia the more it takes to change the temperature of the mass. This means that high frequency drivers can heat up faster than low frequency drivers.

This is especially true during clipping because the driver is converting all its input power from the amplifier into heat while the signal is clipped.

Clipping Facts
-- Any clipped signal can blow a loudspeaker. It does NOT matter if it is caused by the mixer, amplifier OR any other piece of equipment in the system OR whether the amp is at full output.

-- Clipping cannot be detected by electronic or built-in loudspeaker protection circuits and therefore cannot prevent damage from clipping.

-- Loudspeaker power ratings are valid on for un-clipped input signals.

-- Watch those clip indicators on every piece of equipment to avoid ANY clipping.