I have a problem with my M&K speakers. Although they are supposedly shielded, I still get slight shadowing from the speaker that is placed on top of my TV. Using a compass I have found that the greatest amount of magnetism comes from the front facing tweeter - not so much mid range cones - as there is only a grill in front of this, I presume this is where my problem lies. The manufacturer says they are shielded and can be placed on top of the TV - how can this be so, when you cannot shield the grille? Any ideas?