shauns (01/04/83)
A lot of new high-end TV sets, `component' systems in particular, advertise
heavily the fact that they have stereo-ready audio circuitry and
stereo outputs to your home hi-fi. A few even
go so far as to simulate a stereo effect with the standard mono network feed.
After playing with a lot of these sets in the store, I'm very unimpressed with
stereo audio, and have some theories on why.
Have you ever noticed the `hole-in-the-middle' effect that occurs with a
stereo simulcast of, say, a symphony orchestra? The video shows the orchestra
from about the middle of the theatre; the violins are playing-you can see them-
but the audio says that their position is about 2 feet to the left of the
screen. Then the horns come in-2 feet to the right. There doesn't appear to
be any sound coming from the screen itself!
It seems to me that this is a result of the perceived (and recorded) sound
field not correlating with the perceived visual field. In the average home
stereo setup, the sound field is as wide (maybe wider) as the angular
displacement between the speakers, usually 60 degrees. A 25" TV set
viewed from about 8' away covers only 9 1/2 degrees.
To match the visual field, the dispersion of the stereo audio signal would
have to be severely reduced-in fact to not much more than monophonic. If
this is the case, why bother with stereo?
Note that stereo movie audio works because the speakers are spread
across the screen and their limits coincide with the visual field limits,
creating the illusion that the sound is actually coming from the screen.
Also, large screen TV mfgrs have had to resort to speaker systems that aim
TOWARDS the screen and bounce off it at the viewer to avoid the `hole-in-the-
middle'.
I think that the mfgrs should concentrate on providing a good quality monophonicspeaker system, at the screen, for small screen sets and forget about stereo
until wall-sized TV systems are feasible.
Comments?
Shaun Simpkins
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