Surround Sound
Multi Channel audio has been around for some time now, first appearing in cinemas in the 1960s. In the 1970s Quadraphonic sound was introduced to the general public and, due mainly to various different incompatible systems confusing the consumer, it didn't take off.

Today with the popularity of Home Cinema systems, surround sound based on either Dolby or DTS encoding standards has started to become very popular. Although on the face of it things appear to be less confusing this time around, nothing could be further from the truth. Surround sound can be true equal four channel sound sources with the addition of a centre 'dialogue' speaker and a sub woofer but more commonly it is a stereo image with additional effects and ambience appearing from the rear speakers.

Not only is the way the channels are interpretted inconsistent but there are many different multi speaker systems using 3.0, 4.0, 4.1, 5.1, 6.1, 7.1, 8.0 or 10.2! The figure to the right of the decimal point indicates the LFE (Low Frequency Effects) channels. These occupy a fraction of the bandwidth taken by a normal channel (0.005 of a channel to be precise, but .1 represents it more simply).