Words simply cannot describe the range of sounds we hear. Describing the source of a sound is far easier than describing the sound itself, and many catalogers resort to this approach. Source descriptions are much less useful if we are unfamiliar with the sounds produced by the source, for example, llama vocalizing, slab of steel emerging from a furnace, and water lock gates opening . Moreover, the source of a sound is often unknown. No one has a greater need to locate sounds than sound designers , creative professionals who incorporate sound effects with dialog and music to produce sound tracks for feature films and television programs.
Sounds are the primary concern of sound designers, and they care little about the source of sounds.
In fact, sound designers have made a science out of fooling the listener's ear. He tells of how a single recording of an African waterfall, when played at different speeds, has been used convincingly to create the sounds of printing presses and atomic bomb explosions. Fictional characters provide a wonderful opportunity for creativity. In the Star Wars movies, the voice of Chewbacca came from a walrus. In the movie, Jurassic Park , a power saw was used for the sound of the T-Rex.