depending on the brand you can get it reconed and coiled. what brand is it? also don't push against it while it is playing, remove the driver and evenly push into the cone and lightly light it from the back. also tap the cone and check for spider fatigue. Has the speaker been dropped at all because the problem could also be a shifted maginet. or the can be something floating in the coil gap. Use a multimeter to check the impedence and bring it to a certified recone center to have it looked at and see if it can be repaired.