FYI: The later versions of the sound were reproduced on KYMA CAPYBARA. http://www.symbolicsound.com/press-THX.html
Not many people know what you have just pointed to and few even would believe it.
THe thing about old systems is that they were all *offline*
I myself used C-Sound and you could run an offline process pretending that you ha 192KHz converters back in the day (which, back then, was impossible).
A few folks knew - those that had a relationship with Stanford or IRCAM or Amblin / Lucasfilm knew also as well as a rare few others.
Then a number of folks got to know.
But the thing about this is that they got lucky ... there was a lot of experimentation an and they got lucky.
Today, with SOLARIS you could get lucky a lot more often
