[..] older computers with crappy soundcards that clip when above 0db on Foobar2000 meters.
After messing around some more, it seems the 'phase' errors only occur with older classical material that was recorded live to analog tape. So I think I answered my own question --- freesurround doesn't play nicely with material that has tape warble or was improperly coupled in the analog mix. Not too surprising, and other techniques, particularly VI Suite, work well with these problematic analog sources. So there's still no one-size-fits-all upmixer, but nothing beats freesurround with a good source.
Hi! MAN!! thank you a lots for your job could you create a VST version of your FOOBAR DSP??Thank you in advance for your anserBest RegardsTony
Thank you for your huge work. Please, create a DirectShow version