technoguy

6.1, which was developed by Gary Rydstrom and Anthony Grimani and is typically delivered as Dolby Digital EX or DTS-ES, adds a Surround back channel to the 5.1 setup. The additional surround back information is stored in the Dolby Digital EX format as a matrixed signal, meaning that audio that is in phase and equally in the Sl and Sr channels will be played in the Surround Back channel. DTS-ES allows for a discrete Surround back signal, but can also be matrixed. Some 6.1 playback systems do use dual-mono Sb channels.