Secondly by keeping the weighting in the LIN mode and
putting the filter into the MAN mode (as detailed on pages 8 & 9),
on its 1kHz centre frequency, the calibration should be within
+0.5dB and –1dB.
Measuring Sound Levels
Use as a normal sound level meter
1 Turn on the meter by selecting the ‘A’ weighting or LIN
response, and switch the filters OUT.
2 Check the battery voltage and the calibration of the sound
level meter.
3 Select the 110dB range.
4 Point the instrument towards the source of the sound to be
measured.
5 Progressively step down the ranges until a reading in the
upper two thirds of the meter scale is obtained.
6 If it proves difficult to read the meter because of excessive or
unsteady needle movement, switch the response to SLOW.
7 Record the sound level reading as the meter deflection
(between 0 and 30), plus the selected range, in dB’s if LIN or
in dB (A)’s if ’A’ weighted.
Eg. A sound level of 94.0dB(A) would appear as a needle deflec-
tion of 24, while using the unit on 70dB range.
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Summary of Contents for GA112
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