Larson Davis SoundAdvisor 831C Reference Manual page 187

Appendix B
B.1 Overview
This appendix presents information for assessing the
sound level meter functionality of the Larson Davis
B.2 Section 9.3
a) Reference Sound Pressure Level
The reference sound pressure level is 114 dB re 20 µPa.
b) Reference Level Range
The reference level range is 0 dB gain (SLM) and High
Range (OBA).
c) Microphone Reference Point
The microphone reference point is the center of the
diaphragm of the 377B02 microphone.
Table B.1 831C with PRM831 and 377B02 Microphone average frequency responses and
corrections Required by IEC 61672-1
Exact 0° Free Field
Frequency Response
Hz dB
251.19 -0.03
316.23 -0.11
398.11 0.12
501.19 0.14
630.96 0.18
794.33 0.15
1000.00 0.00
1059.25 0.00
1122.02 -0.12
1188.50 -0.21
1258.93 -0.39
1333.52 -0.29
1412.54 -0.27
1496.24 -0.13
1584.89 -0.02
SoundAdvisor Model 831C
Measuring Sound Using IEC 61672-1
0° Free Field
1
Wind Screen
Corrections
dB
0.03
0.11
-0.12
-0.14
-0.18
-0.15
0.00
-0.00
0.12
0.21
0.39
0.29
0.27
0.13
0.02
SoundAdvisor Model 831C according to IEC 61672-1
Edition 2.0 2013-09.
d) Periodic Testing
Table A.7, "SLM with PRM831 and 377B02 Microphone,"
on page 10-A lists values of 831C with PRM831 and
377B02 Microphone adjustment data of A-weighted
levels used for periodic measurements.
e) Frequency Response and Corrections
See Table A.7, "SLM with PRM831 and 377B02
Microphone," on page 10-A.
Wind Screen
Effect of
on 831C 0°
Free Field
dB dB
0.03 0.00
0.15 0.04
-0.03 0.09
0.00 0.14
-0.09 0.09
-0.07 0.08
0.00 0.00
0.11 0.11
0.03 -0.09
0.13 -0.08
0.31 -0.08
0.21 -0.08
0.20 -0.07
0.07 -0.06
0.23 0.21
0° Free Field expanded
Corrections uncertainty
with Wind of
Screen on Corrections
831C¹ '@ 95%
dB dB
0.00 0.25
-0.04 0.25
-0.09 0.25
-0.14 0.25
-0.09 0.25
-0.08 0.25
0.00 0.25
-0.11 0.25
0.09 0.25
0.08 0.25
0.08 0.25
0.08 0.25
0.07 0.25
0.06 0.25
-0.21 0.25
B-1