There is a definite difference in percieved sound quality between the 6ch external input and the 2 ch bypass stereo analog imputs on the 950.You can use the external input for stereo only as well,from any source.There is no processing other then the sub out gets baas from any connected channels below 80hz[analog domain]. The difference I notice is a bassier low end,and the soundstage seems to be more laid back,and the tonal balance seems more mellow as well. The 2 ch bypass input is exact opposite. The bass is leaner the upper mids are brighter,and the soundstage seems more forward beacuse of that. Check it out yourself.