X-Array™ Loudspeaker Systems
loudspeaker systems are based on test results
in which parts were stressed to failure. Manu-
facturers typically present the structural-strength
ratings of mechanical components or systems
as either the working-load limit (WLL) or the ulti-
mate-break strength. Electro-Voice chooses to
present the structural-load ratings of the
X-Array™ loudspeaker systems as the
working-
load limit. The working-load-limit rating represents
the maximum load that should ever be applied to
a mechanical component or system. THE USER
SHOULD NEVER APPLY A LOAD THAT EX-
CEEDS THE WORKING-LOAD LIMITS OF ANY
OF THE RIGGING COMPONENTS OR COM-
PLETE LOUDSPEAKER SYSTEMS DESCRIBED
IN THIS MANUAL.
The working-load limits for the X-Array™ rigging
components and complete loudspeaker systems
described in this manual are based on an 8:1
safety factor. The safety factor is defined as the
ratio of the ultimate-break strength divided by the
working-load limit, where the ultimate-break
strength represents the force at which a part will
structurally fail. For example, if a part has work-
ing-load limit of 454 kg (1,000 lb) based on an 8:1
safety factor, it would not structurally fail until a
force of at least 3,629 kg (8,000 lb) was applied;
however, the user should never apply a load to
that part that exceeds 454 kg (1,000 lb). The
safety factor provides a margin of safety above
the working-load limit to accommodate normal
dynamic loading and normal wear.
CAUTIONS for Working-Load Limits and
Safety Factors: The working-load limits defined
by the manufacturer of any rigging component
should never be exceeded. Electro-Voice bases
the working-load limits of its products on an 8:1
safety factor. Other manufacturers of rigging com-
ponents may base their working-load limits on
safety factors other than 8:1. For example, 5:1
safety factors are fairly common amongst rigging
manufacturers because many regulatory agen-
cies call for a minimum safety factor of 5:1.
When an X-Array™ loudspeaker system is in-
stalled where local regulations only require a
safety factor of 5:1, Electro-Voice insists that the
working-load limits of the X-Array™ components
never be exceeded, resulting in a safety factor of
8:1 still being maintained for the Electro-Voice
components. The user is cautioned that some lo-
cal regulations may require safety factors higher
than 8:1. In that circumstance, Electro-Voice in-
sists that the user maintain the higher safety fac-
tor as required by the local regulations throughout
the entire X-Array™ installation. It is the responsi-
bility of the user to make sure that any X-Array™
installation meets any applicable local, state or
federal safety regulations.
3.2 Structural Rating Overview
There are two independent strength ratings that,
together, give a complete description of the overall
structural performance capabilities of any X-Array™
loudspeaker system. They are defined as follows:
1. The strength of each individual rigging
point; which is the combined strength of the
rigging track mounted on the enclosure with
the removable rigging-hinge and/or rigging-strap
assemblies.
2. The total strength of the overall enclosure;
which is a function of the combined forces from all
of the rigging points acting on the enclosure as a
whole.
The array designer must be aware of the working-
load-limit ratings and the loads being applied to
the individual rigging points and the overall enclo-
sure. An X-Array™ loudspeaker system is only as
strong as its weakest link. It is usually the case
that one of the working-load limits will be ap-
proached sooner that the other. WHEN SUS-
PENDING ANY X-ARRAY™ LOUDSPEAKER
SYSTEM OVERHEAD, THE WORKING-LOAD
LIMITS MUST NEVER BE EXCEEDED FOR
EACH INDIVIDUAL RIGGING POINT, OR THE
OVERALL ENCLOSURE.
The forces acting on each individual rigging point
and on the overall enclosures in an X-Array™ fly-
ing system will vary with each array configuration.
Determining the forces throughout an array
requires complex mathematical calculations.
Electro-Voice engineers have, however, defined
a set of
simplified structural-rating guidelines that
eliminate the need for the complex calculations
for most array configurations. The interaction of
the complex forces throughout arrays were ana-
lyzed to develop this set of conservative guide-
lines, presented below, to enable a rigger to
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