TB 9-4931-413-40
(2) Turn function switch of sound-level calibrator to 2000, 1000, 500, 250, and 125
Hz, respectively. Record TI meter indication for each position of function switch of sound
level calibrator. Collectively, meter indication will not deviate more than r3.5 db.
b. Adjustments. No adjustments can be made.
10. Weighting Network Response
a. Performance Check
NOTE
The following values shown in parenthesis apply to units with
11/8-inch microphones. Values not enclosed in parenthesis
apply to units with 15/16 inch microphones.
(1) Turn function switch of sound-level calibrator to 125 Hz. TI meter will indicate
between 112.5 and 115.1, (112.3 and 115.3) db.
(2) Turn TI WEIGHTING switch to A. Meter indication will be between 96.5 and
99.1 (96.3 and 99.3) db.
(3) Turn WEIGHTING switch to B. Meter indication will be between 108.4 and
111.0 (108.2 and 111.2) db.
(4) Repeat technique of (1) through (3) above for frequencies and WEIGHTING
switch positions listed in table 3. Meter will indicate within limits specified. If not, record
actual deviation, and prepare chart of correction factors applicable to TI.
Table 3. Weighting Network Response Check
Test instrument
Sound-level
Meter indications (db)1
Weighting
calibrator output
Switch position
frequency (Hz)
Min
Max
250
C
112.6(112.5)
115.2(115.5)
500
C
112.7(112.5)
115.3(115.5)
1000
C
112.6(112.3)
115.2(115.3)
2000
C
111.7(111.6)
115.3(115.6)
250
B
111.1(111.0)
113.7(114.0)
500
B
112.4(112.2)
115.0(115.2)
1000
B
112.6(112.3)
115.2(115.3)
2000
B
111.7(111.6)
115.3(115.6)
