I can tell you how to tell.Put your speakers whereever you want to.If the colors(red yellow pink,skin tone to name a few)don't get blotches your're ok.If they do ;move the speakers pronto.Looking for blotches:If there is a large object with thoes colors along the outer edge it will fade/discolor.Get out a dvd or tape find a place where thoes colors are along the edge (close to where the speakers are) hit pause look.Also if there is an object of the colors I refered to moving on the screen see if it changes as the object goes say to the middle of the screen.WARNING:If the speakers discolor,and are left to long it becomes permanent.End credits of a movie sometimes have yellow writing as a sugestion.thirty inches is as close as I would get,and I have a rr,proj.tv