Let's take the rear-projection "big screen" TVs of the eighties. You could watch these sets only from 10 or so feet away, and were a lot of fun for watching football games, etc. But if you got too close to them you could notice numerous blurry blocks of color which spoilt the image. Nowadays most larger (36" and up) TVs are HDTV-capable and they can provide much crisper resolution than ever before, which means that you can view them at close distance even if you are just watching broadcast TV. Also flat-panel TVs are making it easier to have a big screen TV in your house without taking up too much space in your room. 3. "All right, I know what 5.1-channel sound is. But, tell more about 6.1-channel sound and 7.1-channel sound. What are their benefits?" The 5.1-channel sound is the most widespread form of surround sound. There is a center channel speaker located above or below your TV, a pair of front left and right speakers, and a pair of surround speakers, which play different signals. The subwoofer is used to play just the low bass. So the "5" means the five speakers and the ".1" means the subwoofer. It is a very effective form of surround sound and all new DVD movies I with a multichannel soundtrack have a 5.1 surround option.  The 6.1 channel sound, porvides you an additional rear center surround. The original surrounds are located to the left and right, while the extra rear surround is placed right behind you, and creates its own unique channel of sound.
It's easy to notice how a 6.1- or 7.1-channel setup can be so engrossing. Some movies are encoded for 6.1 surround, but most of them are for 5.1 sound. So the receivers which power a 6.1 system (that is, they can power 6 speakers, and have an output for connecting to a powered sub) usually also involve an option for translating 5.1 sound into 6.1 sound. Their main job is to fill up that rear surround with audio copied from the left and right surrounds which is very effective. The 7.1-channel sound includes another rear speaker. There is no encoding for 7.1-channel sound most 7.1 receivers do special processing to send duplicated sound to that second rear center speaker (a few receivers may do more intelligent processing). So, if you have a 7.1 setup and you're watching a movie encoded for 5.1 sound, the two rear center speakers will be playing a mix of music and effects coming from your left and right surround speakers. If the movie is encoded for 6.1, your two rear center speakers will reproduce the exact same signal — that is, the one created for a single rear center speaker by the engineers who put the soundtrack together.
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