Originally Posted by r2k2d2

well think about it...if you had a bad sub or a blown sub that could lead to this problem. if the sub is blown, it will no longer be 4ohms or 2 ohms or whatever the factory rated it at. if it is blown, it will be very very low, infinitely low. and, the amp is only rated to operate at a certain impedence or it will get to how and blow itself. v=ir where v is voltage i is current and r is resistance. voltage is not really going to change much since your source is a DC battery. so, lets rearrange and solve for i. i = v/r. so, if the resistance goes down, current increases. if resistance goes to 0 (zero) current will reach infinity. so, if the speaker goes bad it could exceed its current rating and burn out the channel.