TB 9-4931-413-50
SECTION I
IDENTIFICATION AND DESCRIPTION
This bulletin provides instructions for the
1. Test Instrument Identification.
calibration of sound-level meter, General Radio Models 1551-C and 1565-A.
The
manufacturer's instruction manual was used as the prime data source in compiling these
instructions. The sound level meter will be referred to as the "test instrument" throughout
this bulletin.
a. Model Variations. Variations among models are described in text.
b. Time and Technique. The time required for this calibration is approximately 2
hours, using the physical technique.
2. Calibration Data Card (DA Form 2416). Maintenance forms, records, and reports
which are to be used by calibration personnel at all calibration levels are listed in and
prescribed by TM 38-750.
Test instrument parameters
and
performance
3. Calibration Description.
specifications which pertain to this calibration are listed in table 1.
Table 1. Calibration Description
Test instrument parameters
Performance specifications
Sound-level range
Model 1551-C: 24 to 150 db above 0.0002 bar at 1000 Hz
Model 1565-A: 44 to 144 db above 0.0002 bar at 1000 Hz
SECTION II
EQUIPMENT REQUIREMENTS
4. Equipment Required. Table 2
identifies the
specific equipment used in
this
calibration procedure. This equipment is issued with secondary reference calibration
standards set 4931-621-7878 and is to be used in performing this procedure.
5. Accessories Required. The accessories furnished with the test instrument are the
only items required to perform this procedure.
Table 2. Minimum Specifications of Equipment Required
Common Name
Minimum Use
Manufacturer, Model, and Part Number
Specification
SOUND-LEVEL CALIBRATOR
No substitute
General Radio, Model 1562-A (MIS-10219)
2