Cinema Sound and the Loudness Issue: Its Origins and Implications

For over five decades after the introduction of ‘talking movies’, the soundtracks of films were recorded in various types of analogue forms, such as variable-area optical film, variable-density optical film and magnetically-coated film. From the 1920s to the early 1970s, the background noise (hiss) inherent in the recording processes limited the level to which the sound could be amplified before the noise became unpleasant and annoying. The cinemas, themselves, were often made from converted theatres, whose acoustics were designed more for reinforcing the voices of live actors, rather than for sound reproduction via loudspeakers. However, these limitations were usually taken into account by the film directors and sound mixers, who kept the soundtracks relatively simple. Actors also tended to deliver their dialogue with a semi-theatrical projection, and in most cases spoke clearly. Accompanying music and effects were usually interspersed with the dialogue, so each occurred in its own time.