To repeat:
Dorten, place the center speaker on the TV. If the shielding is inadequate, the picture would be noticeable. Besides, the magnetic field of the speaker would have to be near the CRTs themselves, not the image, which is merely reflected light. Therefore, it's almost impossible for a rear projector to be affected by a speaker magnet. The weight is negligible.
Larry
www.fineelectricco.com