To those interested in the entry of "talkies" in the movies in the late 20's; go to: http://mixonline.com/TECnology-Hall-of-Fame/wesern-electric-vitaphone-090106/ For many years, theatres had a huge speaker enclosure behind the movie screen.....it was usually the RCA "Voice of the Theater".....had remarkable performance for that day and age. 73 Norm K1AA