Technique used in home THX systems to create a more diffuse, full surround sound environment by splitting up the mono surround channel of matrix surround sound systems (Dolby Pro-Logic) into two channels and feeding them alternate information. This process ensures that the mono surround signal is not localized or located at a specific speaker (combined with the THX requirement of dipole speakers). It also expands the surround sound information to create a large, all-around-you sound field. ecorrelation is used only to enhance surround sound performance from matrixed surround sound formats (the analog Dolby Surround or Dolby Pro-Logic format). Discreet digital surround sound formats (Dolby Digital and DTS) feature stereo, discrete, full-range surround sound channels that operate without decorrelation.