The linear mixing of two or more signal channels at specific amplitudes and phases to form two or more new signals. These new signals can be combined in similar ways to recover the original signals. The circuit topology used for matrixing is called a matrix. Matrixing is a linear addition of signals used to encode directional information, e.g., Scheiber matrixing used in Dolby Surround-sound, and it is not the same as modulation.