I think this really depends on your speakers and your TV. My main speakers are Paradigm Studio 40s and I have them spaced approx. 6' with a 27" TV (soon to be replaced with the Tosh 50HX81) in between. So I guess they are 2' from the tv. I'm sure that 1' would be o.k. The best way to test this is to have you TV on the "BLUE" screen, and move your speakers closer to the TV. If you see ANY "Discolouration" with the Speakers on, then move away a bit at a time until it goes away.
Cheers!
Mass