Speaker coils generate strong magnetic fields. Those fields bend the electron beams used to draw the picture on the faceplate of a CRT TV. In some cases, they can also magnetize the supports in the TV, causing permanent problems. Some speakers are designed to be used near TVs. They include magnetic shielding called MuMetal and can be quite a bit more expensive than unshielded speakers.
These problems don't exist for flat-panel TVs.
Marantz SR7009 avr + MM9000 amp --> Atmos 7.1.4
Fronts=NHT 2.9+AC2, FH+TM=DefTech PM1000, LCR+TM amped