I have tried everything. I spent hours googling this, reading other forums, etc.
I have an HT-E3500 Blu-ray surround set up. It sounds fantastic except that every speaker hisses, and the center speaker has a particularly awful high pitched tone coming from it. You can hear it from 1 to 2 feet away. The hissing can mostly only be heard if you're at least a few inches away.
Samsung has not been any help, PC Richards (where I purchased it) told me this was "normal", and I have tried a surge protector, maing sure the wires don't touch, etc, etc.