MIL-DTL-16225C
NATIONAL CONFERENCE OF STANDARDS LABORATORIES (NCLS)
NCSL Z540.3
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Requirements for the Calibration of Measuring and Test Equipment
(Copies of these documents are available from https://www.ncsli.org or to National Conference of
Standards Laboratories (NCSL), 2995 Wilderness Place, Suite 107, Boulder, CO 80301-5404.)
2.4 Order of precedence. Unless otherwise noted herein or the contract, in the event of a conflict
between the text of this document and the references cited herein, the text of this specification takes
precedence. Nothing in this specification, however, supersedes applicable laws and regulations unless a
specific exemption has been obtained.
3. REQUIREMENTS
3.1 First article. When specified (see 6.2), a sample shall be subjected to first article inspection in
accordance with 4.2.
3.1.1 First article sample. Two (2) first article samples shall be furnished for the tests.
3.2 Material and parts. Material and parts shall be as specified on U. S. Navy Drawing RE-C-49041.
Material and parts not specified shall be capable of withstanding the tests specified herein.
3.3 Salt spray. The loudspeaker shall withstand the test specified in 4.4.7. Following the test, there
shall be no evidence of corrosion, electrical damage, or mechanical damage.
3.4 Application. The loudspeaker shall be suitable for open bridge and other exterior installations and
operation on Naval combatant ships of all types. This requirement stipulates that the loudspeaker shall
be capable of operating under conditions of shock, vibration, roll and pitch, gunblast, and wide ranges of
ambient temperature and humidity incidental to such installations and use.
3.5 Design. The loudspeaker unit specified herein shall be of the radial, reflex horn type.
3.5.1 Major parts. The loudspeaker unit shall include the following major parts.
a. Magnetic, blastproof driver unit complete with diaphragm-voice coil assembly.
b. Hermetically sealed matching input transformer.
c. Volume control.
3.5.2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or
environmentally preferable materials should be used to the maximum extent possible, provided that the
material meets or exceeds the operational and maintenance requirements, and promotes economically
advantageous life cycle costs.
3.6 Electrical requirements (see 4.4.3).
3.6.1 Frequency range. The loudspeaker shall be capable of reproducing, articulately and audibly,
frequencies within the range of 200 to 5,000 Hertz (Hz). There shall be no serious resonance peaks of
such amplitude as to materially affect the quality of response over the operating range or to cause rattling.
The frequency response shall be within the limits shown on figure 1, when tested with a decibel meter at
an angle of 90 degrees off the sound axis (see figure 2).
3.6.2 Power handling capacity. The loudspeaker shall be capable of handling input power up to 10
watts. It shall also be capable of continuous operation at the specified maximum input level without
producing rattles or causing deleterious effects to the windings of the voice coil or to any other parts of
the loudspeaker. The maximum input level shall be considered to be 10 watts at 1,000 Hz.
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