Prof - I only saw the setup in the factory and did not witness a demonstration. But John's explanation did not include a blind component, rather it was a live vs recorded comparison tool. The "band" would play and be recorded live to listeners, and then that recording was played back immediately to the same listeners in the same place - very few uncontrolled variables.
I have read about show demos with a guitarist, etc. between two speakers who may or may not have been playing the strings as the recording of the previous verse may or may not have been coming through the speakers. That's second-hand hearsay, but the boldness itself is impressive.
