Three German inventors, Josef Engl, Hans Vogt, and Josef Engl patented the "Tri Ergon" process.
In 1922, Tri-Ergon announced the development of a glow lamp light modulator for variable density
recording of sound. The Tri Ergon Process uses a technology known as variable density, which
differed from a later process known as variable area. The Tri Ergon process had a pattented
flywheel mechanism on a sprocket which prevented variations in film speed. This flywheel helped
prevent distortion of the audio. Tri Ergon relied on the use of a
photo-electric cell to transduce mechanical sound vibrations into
electrical waveforms and then convert the electrical waveforms into
light waves. These light waves could then be optically recorded
onto the edge of the film through a photographic process. Another
photo-electric cell could then be used to tranduce the waveform on
the film into an electrical waveform during projection. This
waveform could then be amplified and played to the audience in the
Theater. The Fox Film Corporation acquired the rights to the Tri
Ergon technology in 1927.

In 1926, Theodore W. Case and E. I. Sponable demonstrated their sound-on-film developments to
representatives of the Fox Film Corporation, and to William Fox himself. The Fox-Case Corp. was
organized to exploit the system, which was given the name Movietone. The Fox Film corporation
started making Movietone News newsreels. One of the first newsreels was Charles A. Lindbergh's
fabled takeoff for Paris. The years 1928 and 1929 were marked by rapid expansion in facilities and
personnel, successful showings and stepped-up schedules of newsreel releases. In March of '29, the
making of silent pictures by Fox was discontinued.

The Vitaphone was a sound-on-disc system using
multiple 33 1/3 rpm discs developed by

Bell Telephone

Laboratories

and Western Electric. The Vitaphone

system was first embraced by Warner Brothers. In
August 1926, Warner Brothers debuted the first
Vitaphone film

Don Juan

. Don Juan was the first

mainstream film that replaced the traditional use of a
live orchestra or organ for the soundtrack. However,
inDon Juan there was no dialogue in the film.

The first movie with dialogue, or "talkie",
was

The Jazz Singer

. Although, originally

conceived as a singing picture with no
dialogue, Al Jolson ad-libbed some
dialogue on the set and the talkies were
born. In 1928, Lights of New York was
released by Warner Brothers as the first
all-dialogue film.

Later in 1928, Disney's

Steamboat Willie

premiered. It was the first

Later in 1928, Disney's

Steamboat Willie

premiered. It was the first

film to completely create a soundtrack in post production including
sound effects, music, and dialogue.