A-A-50621 Loudspeakers, Permanent Magnet For Shipboard Entertainment Systems

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A-A-50621

4. Finish. Metal surfaces shall be finished with a corrosive resistant latex or epoxy paint, in the specified color, in accordance with best commercial practices. Composite materials shall be finished in the color specified in the contract.

 (b) Circuit label. A printed schematic of the loudspeaker enclosure wiring shall be permanently affixed to the inside of the enclosure where it will be easily readable with the cover open. It shall show wire color coding, terminal designations and selector switch connections and functions.

3. Reliability. Speaker enclosure shall have a MTBF of 25,000 hours.

4. Types of loudspeakers. Loudspeakers shall be of the following types:

(a) Loudspeakers – LS – 443/WIH

(b) Loudspeakers – LS – 443/WIH

(c) Loudspeakers – LS – 543( )/SIC

5. Loudspeaker input. Loudspeaker built to this specification shall accept an input from a 70 7-volt line.

6. Switches.

(a) Channel selector. The channel selector shall be a 5-positions switch. It shall be so connected that it will switch its two output leads to any one o 4 separate inputs. The unconnected switch position shall be at the counter clockwise (CCW) end of the rotation and shall be marked “OFF”. The output of the channel selector shall be fed to the volume selector.

(b) Volume selector. The volume selector switch shall be a 6-position switch. It shall connect one lead from the channel connector to various taps of the line-to-voice coin transformer, with volume increasing in the clockwise (CW) direction. The other lead from the channel selector shall be permanently connected to the other side of the transformer.

7. Multiple speaker operation. To provide for multiple speaker operation, the two input leads to the volume selector switch shall be made available on a terminal strip.

8. Shock. The loudspeaker built to this specification shall meet the shock requirements of MIL-S-901 for Lightweight, Grade B, Class I, Type A, Hull mounted equipment.

9. Stray magnetic field. The maximum value of a stray magnetic field measured on a horizontal plane 76 cm below the axis of the loudspeaker magnet shall not exceed 1.05 milligaus (105 gamma). The stray magnetic field limit shall apply only to LS-543 ( )/SIC loudspeakers.