I remember seeing pics of those live vs. recorded demonstrations onhwy61, in the 1960’s/early 70’s AR ads and sales literature. They were done in NYC, at Carnegie Hall, I believe.
By the way Bose 901 fans, the "double acoustic space signature" effect onhwy61 mentions is one of the things wrong with that speaker. The 89%/11% reflected-to-direct sound Amar Bose measured in music halls, and which the 901 mimics, ignores the fact that recordings of orchestras in those halls, Dr. Bose’s standard for recorded sound, already contains the hall’s reflections. The 901 then doubles the effect. For the 901 to work correctly, music would need to recorded, as onhwy61 said, either outdoors or in an anechoic chamber, free of reflected sound. And then there is the case of studio-recorded music, which bears no semblance to the direct vs. reflected sound of large halls and churches, making the speaker absolutely inappropriate for studio-made recordings. An extremely flawed speaker conception and design.