If you don't see smoke, then it's not burning (not burning enough anyways, lol). It could just be the smell of your coils heating up. Technically, they were in a sealed (airtight) box before right? So if they smelled funny when the heated up, you wouldn't have ever smelled it before. Run 'em and get 'em to smell and see if you can locate the root of your stinky sub. If you're not seeing anything, I don't know what else to tell ya.