Electrovoice xb Reference Guide

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X-Array™ Loudspeaker Systems
mathematical calculations. All of these forces
must then be compared to the working-load limits
detailed below for each of the rigging points and
the overall enclosures. The reader should consult
an experienced structural engineer to perform the
complex structural analysis. WHEN SUSPEND-
ING ANY X-ARRAY™ LOUDSPEAKER SYSTEM
OVERHEAD, THE WORKING-LOAD LIMITS
MUST NEVER BE EXCEEDED FOR EACH INDI-
VIDUAL RIGGING POINT, AND THE OVERALL
ENCLOSURE.
Rear Rigging Structural-Strength Ratings:  The
working-load limit of each individual rigging point
on the rear of an X-Array™ enclosure is depen-
dent upon the rigging-track/bracket assembly as it
is mounted in the enclosure, the specific remov-
able rigging-hardware assembly and the angle of
pull. The structural-strength ratings for the Xrhg
grid hinge, Xrhp pickup hinge, Xrhl linking hinge
and New Haven NH32102-2 fitting are shown in
Figure 20
.
The Xrhg grid and Xrhp pickup hinges have iden-
tical structural-strength ratings, as shown in
Figure 20a
. It should be noted that the front-to-
back-angle range is only 270° because the hinge
chains can only be put into tension and the enclo-
sure prevents a full 360° rotation. It also should
be noted that the Xrhg grid and Xrhp pickup
hinges are rated only to be used over side-to-side
pull angles of a maximum of ±10° as shown in
Figure 20a
. The front-to-back ratings are valid
over the entire side-to-side range of ±10°.
The front-to-back structural-strength ratings for
the Xrhl linking hinges shown in 
Figure 20b
 cover
a full 360° rotation. Although it is not possible to
put the hinge into tension over 360°, it is possible
for the linking hinges to go into compression when
pull-up straps are employed. Therefore, the 360°
rating is necessary to accommodate both tension
and compression. It also should be noted that the
Xrhl linking hinges are rated only to be used over
side-to-side pull angles of a maximum of ±5° as
shown in 
Figure 20b
. The front-to-back ratings are
valid over the entire side-to-side range of ±5°.
The structural-strength ratings for the New Haven
NH32102-2 fitting, shown in 
Figure 20c
, do not
vary with the angle of pull both side to side and
front to back. Therefore, only a single rating is
stated instead of a graph showing variations with
angles.
It should be clarified that all of the structural-
strength ratings shown in 
Figure 20
 are for a
single rear rigging point. There are, however, two
rear rigging points on the enclosure – each hav-
ing the structural-strength ratings shown in
Figure 20
. The rear rigging strength ratings are
identical for all of the X-Array™ loudspeaker
model enclosures.
Front Rigging Structural-Strength Ratings:
The working-load limit of each individual rigging
point on the front of an X-Array™ enclosure is de-
pendent upon the rigging-track/bracket assembly
as it is mounted in the enclosure, the New Haven
NH32102-2 double-stud fitting and the angle of
−α
α
α
−β
β
β
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