Wow. Thanks for the post. I'm going to send it to friends. The South Bay Galleria is a nearby shopping center where I live.
What was particularly enchanting was that the musical effect was all entirely human voices with no musical accompaniment. It takes singers with really excellent pitch and tone control to sing without musical instruments in the background. Dial back the clock...When they were just getting started, Roy Orbison was on tour in England and the the Beetles were appearing as lead in's for the Roy Orbison main attraction. I think I'm remembering a Paul McCartney comment. Roy Orbison sang one of his songs with absolutely no musical accompaniment. The Beetles, Paul, expressed surprise at how powerfully Orbison could sing without musical accompaniment. For a good example of Orbison's voice control, do a YouTube for Pretty Woman.