System Overview
The CSC Series three-way screen channel loudspeaker systems from EAW address many issues raised
by the changing design trends of modern cinemas. The features and benefits of this product design are
manifested in two models at the present time: the CSC923 (and its biamplified version, CSC923X), and the
CSC723 (and its biamplified version, CSC723X).
The CSC923 is intended for screen channel use in very large cinemas exceeding 90 feet (27.4 meters)
in length from screen to last row. The CSC723 is intended for screen channel use in cinemas up to 90 feet (27.4
meters) in length from screen to last row.
The challenge of coverage in steeply-raked seating areas
The primary design feature of the CSC Series is its remarkable asymmetrical mid and high frequency
horn designs. While the predominant theatre design of new construction sites includes “stadium style”
seating plans, loudspeaker manufacturers have only begun to actually adapt speaker designs which attempt
to address this room geometry. Although the concept of asymmetrical pattern horns has been in existence for
some time, it has only recently surfaced as a viable approach for the specific requirements of cinema sound.
The application of this horn design for cinema makes particular sense because we have a known “standard”
room dimension proportion (length x width); the most significant variable is scale and floor slope. But, as
any loudspeaker designer knows, any change
to room geometry changes the coverage you
can expect from a given horn design.
Conventional 90º x 40º constant
directivity horns do a good job of providing
even coverage for traditional moderate-slope
cinemas. The trade-off of on-axis positioning
against seating in or out of the horn’s defined
coverage pattern results in a fairly even SPL
throughout most seating areas.
Once the floor slope is increased, this
trade-off becomes off-balance; now the closest
seats in front are brought into the coverage
pattern. Attempting to aim the horn for even
coverage results in making a new trade-off
between providing good HF to either the
farthest rows or the nearest rows. If the conventional horn is aimed to reach the last rows, HF coverage in the
front rows will suffer, and vice versa. Another issue is the energy directed toward the ceiling, now that the
conventional horn is aimed upward for the back rows. This is not only wasted energy, but also potentially
reflects energy from the ceiling back into the seating area, which could interfere with dialogue intelligibility.
A horn designed to provide an asymmetrical coverage pattern will produce a pattern which projects
energy directly on-axis and downward, instead of equal angles above and below its center axis. Thus much
of its energy reaches the back rows, while
the seating area in front is also still well
within the horn’s defined coverage pattern.
Both the HF and MF horns in the
CSC Series feature an asymmetrical shape
which produces a coverage pattern which
can be described as 80 to 90 degrees hori-
zontally by 50 degrees vertically. The range
(80-90 degrees) of the horizontal pattern
produces even coverage on the seating area
because, to the horn, the seating area
appears trapezoidally-shaped. This helps
minimize energy directed to the walls of the
theatre, and focuses coverage to the audi-
ence.
40 degrees vertical
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