MIL-DTL-24223-1 Loudspeaker, Shipboard Announcing Systems Encased, 70 Volt, 1 Volt-Amperes

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MIL-DTL-24223/1B(SH)

Draft Dated 14 January 2014

PHYSICAL REQUIREMENTS:

Description: These loudspeakers shall be of the permanent magnet direct radiator type with a diaphragm (or

cone) made of water resistant material, having a nominal 6-inch diameter. The loudspeaker enclosure shall be

designed for bulkhead mounting and shall contain the loudspeaker unit and a matching line transformer.

Dimensions and weight: See FIGURE 1.

Front face assembly: The front face assembly shall mount the loudspeaker element, transformer, volume

control switch (if applicable). The front face assembly shall be chain bolted to the mounted enclosure.

Degree of enclosure: Except for the opening required for acoustic radiation, the enclosure shall conform with

the totally enclosed requirements of MIL-STD-108. The opening for acoustic radiation shall be covered with mesh

or perforated metal not less than 0.025-inch thick. Mesh openings or perforations shall be not larger than 9/32 inch.

Where required for servicing internal assemblies, the mesh shall be removable.

Enclosure construction: The enclosure shall be provided with a removable cover to provide access to all

interior parts and the enclosure mounting holes. The enclosure cover shall be secured by means of captive screws

engaging in tapped holes provided in the enclosure. A beaded chain shall be attached to the fixed portion of the

enclosure and to the cover by means of screws. The chain shall support the enclosure cover when the enclosure is

opened for servicing. The chain shall be enclosed in a plastic sleeve and shall be of such a length as to prevent

strain on the loudspeaker wiring when the cover is suspended by the chain. Removing the cover shall not involve

disturbance of incoming cables and terminal tubes. Part mounting fasteners shall be secured so as not to require

demounting of the enclosure for part replacement. Parts shall be mounted so that their terminal markings are visible

with the enclosure cover open. The enclosure shall be provided with a �-inch (drainage) hole on the bottom front

edge of the mounted portion of the enclosure. The center of the hole shall be a maximum of 1.25 inches from the

center of the surface.

Coatings: Aluminum and aluminum alloy parts shall be pretreated and painted. The pretreatment shall be

either anodized in accordance with MIL-A-8625, or chemically pretreated in accordance with MIL-DTL-5541. It

shall then be primed with a single coat of a material conforming to TT-P-645 or TT-P-644, and a single top coat of

enamel conforming to MIL-DTL-15090 class 2, or coated with a polyester powder (equivalent to the weather and

corrosion resistance of polyester triglycidyl isocyanurate (TGIC)) rated for use in marine environments, designed to

last longer than the active loudspeaker element. The color shall be haze gray, color No. 26270, in accordance with

Fed. Std. 595C.

Cable entrance: The loudspeakers shall be designed with a large enough surface area to admit cable through the

bottom of the enclosure via two stuffing tubes. The stuffing tubes and plug will be in accordance with size 2 of

ASTM F1836M. The stuffing tubes will be furnished by the manufacturer. One hole shall be provided with a

plastic plug.

Direct radiator diaphragm material: The radiating diaphragm (or cone) shall be of water resistant material such

that the loudspeaker unit is capable of meeting the loudspeaker performance requirements of MIL-DTL-24223.

Magnet structure: Magnet structures for loudspeaker units used in the LS-530()/SIC and LS-531()/SIC shall be

of special design to limit the amount of stray magnetic field surrounding the structure.

Special marking for LS-530()/SIC and LS-531()/SIC loudspeakers: An instruction plate shall be provided on

the front of these loudspeakers to indicate the correct mounting position to minimize stray magnetic field below the

loudspeaker. The instruction plate shall be in accordance with MIL-DTL-15024 Types A, B, F, or H; attachment

shall be by mounting screws.

PERFORMANCE REQUIREMENTS:

Power input: Volt-ampere input specified in TABLE I shall provide at least sound pressure output, indicated in

Sound pressure output: Sound pressure output shall be measured at the distance identified in TABLE I.