New! 6.1 Dolby EX Surround Sound!

While changing the channels, I was on CNN-HD and noticed my audio system was picking up a Dolby EX 6.1 channel audio decoding flag. What this means is that the digital surround audio Dolby signal my system was picking up and decoding directly from my U-Verse HDMI connection was sending a signal that the standard 5.1 channel audio stream contained an extra surround channel for center back audio compressed within that signal. A modern audio system seeing that signal would extrapolate that extra channel in order to create a more immersive surround experience. Systems with two back channels (7.1) would split the center back channel between the left and right back channels instead of to a single center back surround channel. 5.1 audio uses three front channels, two surround channels, and a low frequency channel. 6.1 adds a back-center channel. 7.1 replaces that back center channel with two surround back channels for a total of four surround channels (surround left, back left, back right, surround right).

So far, I've only noticed CNN-HD using the 6.1 Dolby EX format. This would be better used for the movie channels, but I have not checked all the channels yet to see if any more have this.