Does a DVD need to have a matrixed 6.1 soundtrack to experience a matrixed 6.1 surround? What I really want to know is, can't a 6.1 receiver take a 5.1 soundtrack and "matrix" the back surround channel? My copy of Terminator 2: Ultimate Edition says there are two soundtracks - a DD-EX 5.1 and a DTS-ES 5.1 soundtrack. I'm pretty confused about that. Can't a 6.1 receiver derive a matrixed back surround channel from ANY DVD encoded with a 5.1 soundtrack? It just doesn't make sense to me to have a movie encoded in with a matrixed 6.1 soundtrack. Can anyone elaborate on this and tell me what I'm missing? Thanks in advance.