I just setup my surround speakers for my 5.1 setup and they are directly to the left and right of my couch about 6-7 feet from the center of the couch which sounds really good. They are on 24" speaker stands which puts the tweeters at ear level. I noticed that dolby recommends that your surround speakers be 2-3 feet above ear level. How important is that? Should I sell my 24" stands and go for some 40" stands?