As more people move up to the latest flat panel, widescreen televisions, they quickly realize that the onboard speakers simply don't deliver much in the way of sound quality. This has led to more surround sound installations. Originally, such systems were designated 5.1, meaning there are five full-range speakers plus a subwoofer (the .1). Today, we have 6.1 and even 7.1 amplifiers and receivers. The front main speakers (left, right and center) are easy, but where do you place the surround sound speakers? You can take a clue from the surround system of your local cineplex. The left and right surrounds in any of the three surround configurations would optimally be placed to the left and right and just slightly behind the "sweet spot" (where you would be seated to get the full effect of surround sound). Placing them higher than ear level enhances the ear's ability to discern where the sound is coming from (directionality). In theaters, you'll see most installations have the surrounds somewhere near the ceiling of the auditorium.
Okay, that's good for basic 5.1 systems, but what about 6.1 and 7.1 installations? Dolby Digital EX adds a sixth mono channel at the back, but though it's a mono channel, it's best realized using two far rear speakers mounted high up on the back wall at angles between 135 and 150 degrees from the sweet spot. That's a 6.1 system and a 7.1 system (Dolby Pro Logic IIx for example) uses the same placement, but in this case, the rear speakers have a synthesized stereo signal for enhanced realism and more front-to-rear impact. There are lots of relatively inexpensive surround sound systems, but only by using the best quality you can afford will you get the most dynamic surround sound experience.