Hi, I just bought and fitted a Sony CDX-S2000 head unit. Which says on it 4 x 50W. Now my speakers are 2 10cm 20W Normal 110W Max. I assume whats happening is that the speakers are getting to much power and are crackling because they cant cope with it. What kind of speakers would solve this, or is there some sort of resistor I can fit to lower the power, of the head unit, and stop the crackling ?