Matching Visual and Auditory Cues in Films

[Richard M Warren <rmwarren@xxxxxxxxxxx>]

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.