Surround sound speakers are part of a nice home theater system and their purpose is to immerse us and “surround” us with sound. Speakers are placed around the listening area to achieve this effect.
Surround sound speakers can take a video of an airplane and make it seem like it is flying overhead. As the plane flies overhead, the side and rear channels are hand off the signal from the front speaker system and move it from side to rear or side to side. In order for the sound to track correctly, the surround speakers must have their room reflections controlled though proper room treatment techniques.
A balance of sound diffusion and sound absorption techniques are needed to create the correct ambient sound “image” at the viewing/listening position from the surround speakers. In a surround sound setup, it is important to minimize ceiling and wall reflections because these interrupt with the intended direction of the sound coming from your speakers and will minimize the effect of the surround sound. Once you have used the correct amount of absorption, diffusion panels can be used to spread a more defined signal out across a wider area along the sides and rear of your rooms.
Surround systems are a bit harder to setup given the numerous directions of sound waves. However, once you set them up properly, they sound great and give a truly immersive listening/watching experience.