12. CALIBRATION
1) Prepare the optional " SOUND CALIBRATOR ", such as
" SC-941 " or " SC-942 " ( set range to 94.0 dB ). Power
on the Sound Calibrator & plug calibrator output socket
into the " Microphone " head ( 3-8, Fig. 1 ) of the
Sound Level meter.
2) Select " Time Weighting " at " Fast " position.
3) Select " A " weighting.
4) Adjust the " Calibration VR " ( 3-12, Fig. 1 ) carefully
with a " - " screw driver until the display reading value
within " 94 +/- 0.2 " dB.
13. FREQUENCY WEIGHTING
CHARACTERISTICS OF A & C
NETWORKS
Frequency A Weighting C Weighting Tolerance
Charac. Charac. ( IEC 61672
Class 2 )
31.5 Hz -39.4 dB -3 dB ±3.0 dB
63 Hz -26.2 dB -0.8 dB ±2.0 dB
125 Hz -16.1 dB -0.2 dB ±1.5 dB
250 Hz -8.6 dB 0 dB ±1.5 dB
500 Hz -3.2 dB 0 dB ±1.5 dB
1 KHz 0 dB 0 dB ±1.0 dB
2 KHz +1.2 dB -0.2 dB ±2.0 dB
4 KHz +1 dB -0.8 dB ±3.0 dB
8 KHz -1.1 dB -3 dB ±5.0 dB
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