neebis said:
With the DC48 track, my receiver takes the Digital 2.0 from optical S/PDIF and automatically detects and decodes it as Prologic and I have 5 speakers (L,C,R,LS,RS) plus a powered subwoofer. So I was listening to it as proper surround, not just 2 channel/2 speakers. I might be able to force it to Prologic II, but I didn't think Prologic II was around in 1993.

No, but I believe dpl2 is supposed to be 'backwards compatible' and is preferred even for older surround mixes.
I wouldn't mind hearing someones thoughts on a comparison of the two (and maybe also neo6 and what have you).

By the way, did you use the latest version of ATSurround 1.0? Do you know if there is a big difference in output between that and the older freeware 0.1.6a? Would the AS2 setting be the equivalent of the active matrix you used? Or ASr?

Yes I did use the latest version, some of the settings were renamed and there's only one active matrix setting, I'm not quite sure which of the older ones it corresponds to..