What is the importance of having AC-3?
AC-3 is one form of Dolby Digital surround-sound which allows the user to experience a virtual reality of sound created with a matrix of 5 speakers and a subwoofer (known as a Low Frequency Effects channel). Currently the 4DTV IRD will allow the user to listen to Dolby Digital sound in monaural, stereo and pro-logic surround sound. The HDTV protocol allows the use of true 5.1 channel AC-3 sound and the user can access this sound on the high definition channels with the addition of the HDD200 decoder. On the surface of it Pro-logic and AC-3 seem very similar: they both use five speakers and a subwoofer, speaker positioning is identical, both systems offer total immersion into the movie sound-field, wide dynamic range, and good detail. Look first at Dolby Pro-logic (which is identical to Dolby surround sound and THX in a conceptual context). Dolby Pro-logic is a system that provides left, center, right and surround channels from a 4-2-4-matrix. It works like this… The sum and differenc
