Williams, for example, hauls around his own sound equipment to movie sets and usually hires and manages at least two other people to work with him--a microphone boom operator and a person to string microphone and audio cable. And the rapid pace of change means William must often attend training classes and read technical journals to keep abreast of new technology.
His job is just one of several, however, that shape the final sound that movie-goers hear. While Williams records dialogue on the set and may make special recordings--such as the cricket and bird noises he recorded for "Field of Dreams"--many sounds are produced artificially in the studio.
Some of the buffalo stampede sounds in "Dances With Wolves," for instance, were made by post-production crews banging rocks, coconuts and dirt-packed shoes into soil filled with microphones. While some in Hollywood claim that such post-production techniques have diminished the importance of on-location sound mixers such as Williams, others say his job remains critical.
"There is a misconception that with technology you can fix anything," said Kevin Hooks, a producer and director who made the film "Heatwave." "If you listen to a film carefully, you will get an idea of how important it is to have good production sound. In 'Heatwave,' for instance, we had 200 to 300 rioters and the sounds of bottles breaking. . . . In order for those things to be heard convincingly on film you need someone with the experience of Russell Williams to record it right the first time."