---,you have to remove the voice coil -measure the burnt voice coil from top to bottom and measure the windings length , then replace it with a new voice coil --looks easy on regular woofers but these concave dust caps , I've never seen a rebuild done , as far as tonal quality , I would think that an identical voice coil of the same width , length as far as windings should result in the same ----you're only replacing the voice coil , and not the cone which is the sound changer -