Depending on how it smells it could be any number of things. Formaldehyde is usually a cap. Burnt dog crap is a resistor. A hot electronics smell that leaves a metallic taste in your mouth is usually a choke.
If you can see the bass speaker cone, is it intact? If so it’s probably the amp or a bit of circuitry that is made to burn out to protect the speaker.
Basically, those units are not made to be repaired, just replaced. You could look into repairing it, but it will cost you more in parts and your time than it would to just get a new one. If you have a soldering iron, a DMM or a O’Scope I can talk you through it.
If you don’t know what those things are, buy a new one.