Hello! Does anyone know how to remove center speaker from Canton sound system? I managed to remove speaker grille. But that speaker looks odd. Workshop manual says that remove screws but im my car there is some plastic knobs. 
 

Thanks!

Answer to my own question. Speaker is bolted from below. So bolts are upside down. You need to unscrew them by removing radio screen and there is also something else on the way behind screen. I actually just cut that speaker out with soldering iron by melting that plastic frame. Just needed to change that speaker and there is no intention to put it back. But i hope this helps someone else.