Dolby Laboratories CP650, Руководство по установке

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Dolby
®
Model CP650 Installation Manual Front-Panel and Alignment Overview
3-10
The final factor is masking of the screen. The masking curtains must be drawn back
sufficiently to clear the left and right screen speakers before any adjustments or
measurements are made. The high-frequency horns should clear the screen frame and
be mounted as close as possible to the screen. Conventional black felt side-masking
can severely restrict high-frequency response. Consequently, there would be severe
losses if the left and right loudspeakers were equalized with the masking set for a
2.35:1 film, and then the masking were brought in for a 1.85:1 film, thus obscuring
the outer speakers. To avoid this problem, some theatres have installed acoustically
transparent masking cloth, and others leave the masking open whenever they are
showing a 1.85:1 film with a stereo soundtrack. Moving the speakers towards the
center of the screen to clear heavy masking is not a good solution, since the stereo
separation would be degraded.
Repainted screens cannot be used for quality sound playback, because the
perforations, which allow the high frequencies through the screen, can become
clogged with paint.