Usage, tear and wear are not the only causes of failing subwoofers. There are in fact many reasons why subwoofers fail. Because of their complex design and cheaper subs using short lasting material, subwoofers can often die within their first few years, particularly if used heavily. Like any highly used electronic product, car subwoofers can fail at times, but also can be fixed.
A common is cause of subwoofer failure is the lack of power, which is caused by not enough amperage reaching the electromagnet coil, in turn causing the permanent magnet and electromagnetic coil to interact differently. This obviously drastically alters the way the subwoofer works and stops the subwoofer from doing its job. Check that that amp is channeling enough power to your woofer and make sure it is a compatible amp for you sub.
Another widespread problem is overheating. Like any electronic product, if used intensely, it is bound to overheat. Although the first time the product overheats, it may not cause obvious problems, it can if repeated cause long term problems to your subwoofers. It may cause damage to the woofers components, in turn causing the subwoofer to stop functioning. To avoid overheating subs, when purchasing subwoofers look out for a sub with a ventilation system, which will keep your system cool. Also, always place your subwoofer in a ventilated area, avoid compacting close together with other audio components and don’t place in an area without much air flow, such as the boot.
A prevalent cause of subwoofer failure is the short circuit, which causes that vital signal never to reach its destination, the sub, causing the sub to fail. The most lethal short circuit is the short circuit at the terminal of the subwoofer. It stops the electrical current and signal ever reaching the sub, meaning no power and in turn no sound can be produced. Short circuits in the subwoofer coil are also a common determiner of sub failure. Coil short circuits often mean there is not enough power to drive the cone, stopping the correct movement that is needed to produce the sound. Short circuits can be annoying, but may be fixed by a professional depending on the damage.