10. Describe 3 major problems on why did it take so long to put sound on films. What were the technical problems?

The problem to put sound on films started as early as the invention of the motion picture itself.  There were many inventors that worked to penetrate the barrier between film and sound.  There were three major problems persisted, leading to motion pictures and sound recording largely taking separate paths for a generation.

Image from the Dickson Experimental Sound Film
(1894 or 1895), produced by W.K.L. Dickson
as a test of the early version of the Edison Kinetophone,
combining the Kinetoscope and phonograph.

The first issue was synchronization between pictures or projectors and sound recorded machine, where sound were recorded and played back by separate devices, which were difficult to start and maintain in tandem. One example is the gramophone records, known as sound-on-disc technology invented by Emile Berliner, a German-American born, in 1887.  With having a separation between film and sound, it makes filmmaker and inventor to face huge challenge in synchronizing the two into one bowl.

Another problem faced by filmmakers and sound inventors was the sufficient playback volume that was hard to achieve. In other words, the intermittent motion (stop & start) of projector versus the continuous, even-rolling motion required for sound playback had caused the playback audio to hardly justified.  While motion picture projectors soon allowed film to be shown to large theatre audiences, audio technology before the development of electric amplification could not project to satisfactory level.

Lee De Forest (1873-1961)

Finally, there was the challenge of recording reliability. The sound technology achievement back then considered primitive and the sound produced was very low in quality unless the performers were stationed directly in front of the bulky recording devices (acoustical horns, for the most part).  This eventually imposed several limitations on the type of films that could be created with live-recorded sound.  The sound amplification was no way to fill up
a theater with acoustic sound.

All these three issues faced in developing sound-on-film beginning to wash away when Eugene Lauste who had worked at Edison’s lab invented a sound-on-film that was photographically recorded directly on celluloid in 1907.  His invention had led to an invention developed by Lee De Forest in 1919 in which his sound recording technology was photographically recorded on to the side of the strip of motion picture film to create a composite, or "married", print. If proper synchronization of sound and picture was achieved in recording, it could be absolutely counted on in playback. Over the next four years, he improved his system with the help of equipment and patents licensed from another American inventor in the field, Theodore Case.