I am certainly no electrical expert, but if, with your sub 7 feet away from your TV, you're having a problem with the picture on your TV, I doubt the problem is caused by the lack of shielding in the sub. When shielding is a problem, the TV's picture is usually distorted (skewed) and/or one or more of the colors (red, green, blue) looks like it's draining toward the sub. The lack of shielding allows the powerful magnet in the sub to affect one or more of the color "guns'" in the TV interfering with it's proper motion. At a distance of 7 feet, I'd be very surprised if the driver's magnet would have any magnetic affect on your TV
The problem you're having sounds like an electrical problem. Were I you, the first thing I'd do is have a qualified (VERY important) electrician come out and check your electricity. If you have had two 350s crap out on you, and your having "static" on your screen, even if it seems to be caused by the sub (and it may be, which is abnormal), you very well may have wiring problem.
Sorry you have to go through this, but having a QUALIFIED electrician check everything, at the very least, will put your mind to rest that your electricity is safe and functioning properly.
Good luck.
