 On September 17, 1922, the Tri-Ergon group gave a public screening of sound-on-film productions—including a dramatic talkie, "Der Brandstifter" ("The Arsonist") —before an invited audience at the Alhambra Kino in Berlin.By the end of the decade, Tri-Ergon would be the dominant European sound system.In 1923, two Danish engineers, Axel Petersen and Arnold Poulsen, patented a system that recorded sound on a separate filmstrip running parallel with the image reel.