Subject: Matching Visual and Auditory Cues in Films From: Richard M Warren <rmwarren(at)csd.uwm.edu> Date: Mon, 23 Feb 1998 16:17:33 -0600
Greetings: I've been out-of-town, so I am late in joining the discussion you started, Al, with your forwarded message by your student, Jason Corey: >While creating and editing a soundtrack for an animated film, it became >apparent that sounds occurring sychronously in time with visual events on >the screen, had a effect on how I perceived the visuals. For one >particular scene there happened to be a great deal of activity happening >in the animation, with different events happening at different positions >on the screen. Without a sound track there were many events that were >not perceived, until a sound effect was sychronised with the particular >visual events. There is another twist to the problem raised in addition to synchronization of visual and auditory cues -- reverberation. I'll quote a passage from my forthcoming book (plug, plug) now in production by Cambridge University Press: >Maxfield (1930, 1931) described the importance of matching what he called >"acoustic perspective" to visual perspective in making sound movies. It >was stated that since binaural suppression of echoes (which will be >discussed shortly) was not possible with one-channel recordings, the >overall level of reverberation must be decreased below the normal level >to appear normal. He found it necessary to vary the proportion of direct >to reverberant sound by appropriate positioning of the microphone when >the camera position was changed in order to maintain realism: Maxfield >gave an example of a long-shot sound track used with a close-camera shot >which made it seem that the actors' voices were coming through an open >window located behind them, rather than from their lips. He made the >additional interesting observation that correct matching of acoustic and >visual perspective influenced intelligibility -- when a long-shot picture >was seen, a long-shot sound track was more intelligible than a close-up >sound track despite the fact that the increased reverberation would make >it less intelligible if heard alone. Maxfield, J. P. 1930. Acoustic control of recording for talking motion pictures. Journal of the Society of Motion Picture Engineers, 14, 85-95. Maxfield, J. P. 1931. Some physical factors affecting the illusion in sound motion pictures. Journal of the Acoustical Society of America, 3, 69-80.