When I really crank the volume the TV exhibits horizontal interference lines. Someone else complained about this, and the answer seemed to be vibration, cured by adding rubber feet to the speaker. This does not help in my case. If I lift the speaker off of the TV a few inches it still happens, but it is reduced. If I lift it over a foot, the problem is gone. The problem is also eliminated if I disconnect the centre speaker, so it is not caused by floor vibration from the mains (I do not have a sub). So, is the cause sound pressure, or magnetic interference? If it is magnetic, wouldn't there be interference even if there is no sound, since the magnets are still "magnetic" with no input from the receiver?