That’s actually a really good question. Most people think it is because the speakers have gone bad, that… they are ” junk”, or bad product…etc. Or It wasn’t rated at the correct power or something to that effect.
Some of that is true, but the real reason the speakers get blown is that whomever is turning the volume control is NOT listening and pushing their speakers past their limits.
Speaker distorts and the consumer says “f%$k it! It’s rated at 100 watts RMS and I am only “pushing” 75 watts. They should be able to take it…F$#k it!!
And just keep turning the volume up, until they “burn up” (blow)
90% of the speakers blown are not actually blown. The voice calls are burned. This burning is caused by the amplifier which produces AC voltage. This AC voltage keeps heating the voice call up, which is simply very thin copper wire wound on a cardboard tube or an aluminum tube or Kapton tube that is glued? What then happens is the glues start breaking down. The voice coil windings (copper) start heating up and bubbling. Voice coils are just little thin copper wire and AC voltage with current (yes amplifiers do that!!) HEATS UP. That coil of copper wire gets REALLY hot (I am pretty sure in your lifetime you’ve smelled woofers cooking ) Then once the stereo is turned off, the glues cool down with bumps on them from the bubbling and when the stereo is turned back on again…this “bubbles” start rubbing in the voice coil gap. This rubbing causes the speaker to slow down its movement, which causes more heat because the pumping in and out the effect of the speaker moving is cooling the voice coil.
After designing and building speakers for over 40 years I can honestly say I have NEVER seen a “Blown” speaker. Burned? 1,000’s! 10’s of 1,000’s. Remember that YOU are the GAS pedal, and YOU are the BRAKE.
No MATTER what the power rating of the speaker OR the amplifier…if you hear clipping (distortion) TURN IT DOWN!!! Otherwise, YOU are the reason the speaker(s) get “Blown”. No other reason!!!