Sound film "The Clue of the New Pin", a British Lion production using the sound-on-disc British Photophone system. In May, "Black Waters", a British and Dominions Film Corporation promoted as the first UK all-talker, received its initial trade screening; it had been shot completely in Hollywood with a Western Electric sound-on-film system. None of these pictures made much impact. The first successful European dramatic talkie was the all-British "Blackmail". Directed by twenty-nine-year-old Alfred Hitchcock, the movie had its London debut June 21, 1929. Originally shot as a silent, "Blackmail" was restaged to include dialogue sequences, along with a score and sound effects,
Stereophonic sound year later, MGM started using three tracks instead of one to record the musical selections of movie soundtracks, and very quickly upgraded to four. One track was used for dialogue, two for music, and one for sound effects. The purpose for this form of multitrack recording was to make mixing down to a single optical track easier and was not intended to be a recording for stereophonic purposes. The very first two-track recording MGM made (although released in mono) was "It Never Rains But What It Pours" by Judy Garland, recorded on June 21, 1938, for the movie "Love Finds