Dolby Laboratories SDU4 SECTION 2 INSTALLATION AND CALIBRA TION

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SECTION 2INSTALLATION AND CALIBRA TION

Front Loudspeaker Arrangement

The SDU4 is designed for monitoring rooms with either two or three front

loudspeakers. The choice between using either two or three front loudspeakers

depends upon the distance between the Left and Right speakers, (how large the

stereo image is) and how the primary listening area is arranged relative to the

front sound image. In most cases, three front loudspeakers are recommended

with the center loudspeaker located immediately above or below the picture.

The center loudspeaker should be the same type as the left and right loudspeaker

to prevent audible shifts in tonal balance when effects are panned across the

front.

Two front loudspeakers may be adequate in monitoring situations where the

sound image is small to mid-sized (no more that eight feet apart) and the

listening area is relatively small and located on axis between the two

loudspeakers. In these situations, a “phantom” center can be used to reliably

localize the center channel information near the center of the picture.

The need for a center channel in video playback increases as the picture size is

reduced for a given playback situation. This is caused by the increased need to

localize dialogue to the center of the sound image when a smaller picture is

used. In the case where a phantom center (no center loudspeaker) is used, a

smaller picture increases the likelihood that off-axis seating will cause the

phantom to fall outside the picture area.

Left Center Right

Surround

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