actually if you understand how a matrix works it is a very stupid idea, the original prologic worked by routing only the "similar differences" of a stereo track to the surround channel, for instance, with stereo guitars, echo, or phase shifted sounds, it would end up in the surrounds. in order to matrix something it MUST be in stereo, considering pro-logic only creates a mono surround channel, i'm willing to bet nothing came out of the extra matrixing he used. in PLII it is in stereo, if you were to matrix already matrixed PLII, you would just get an exact copy of what's in the now matrixed surrounds. you have to understand how stereo works first. in a movie recorded in stereo, the only way to get a wide presentation of a sound is to mess with the phase of the channels. for instance, if wind is blowing, you would have the exact same recording of wind playing in both channels, but the difference between each channel is the phase is slightly off in the left or right, this is what a matrix picks up on, any spatial information that is not directional as far a being hard R, C, or L, goes into the surrounds. pro-logic one works by doing this but only leaving you with a mono surround channel that is cut off past 7khz. in PLII, it does this in stereo and does not cut off high frequencies and with PLII movie mode, it slightly delays the surrounds from the front channels to increase the illusion of space. anything that goes into the surrounds on PLII gets cancelled out of the fronts, anything that is specifically left, right or center, goes into the LCR channels. PLII is somewhat more complicated because of all it's steering and "intelligent" algorithms but standard pro-logic is simple at best.
