Many speakers for PA or guitar or bass amp or home stereo fail after years of good service. This can be complete no sound failure, or noisy sound type of failure, more commonly known as a "blown speaker". Most 10, 12, 15 & 18" speakers can be reconed for less than the cost of a replacement speaker. The recone process involves stripping the speaker frame down, removing the cone, voice coil, spider, & outer edge gasket. The voice coil gap is checked & cleaned, the frame is cleaned and all new components are replaced. The speaker is essentially rebuilt. For vintage guitar amplifiers, this can help maintain the value of the amp, over a replacement. In some cases the original speaker is no longer made.