Appendix B Measuring Iec61672-1; Overview; Section 9.3 - Larson Davis SoundAdvisor 831C Reference Manual

Appendix
B.1 Overview
This appendix presents information for measuring the sound level meter functionality of the Larson Davis
SoundAdvisor Model 831C Sound Level Meter according to IEC61672-1 Edition 2.0 2013-09.
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.
d) Periodic Testing
Table A.4, "SLM with PRM831 and 377B02 Microphone," on page 6-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.4, "SLM with PRM831 and 377B02 Microphone," on page 6-A.
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
SoundAdvisor Model 831C
B Measuring IEC61672-1
0° Free Field
Effect of
1
Wind Screen
Corrections
dB dB
0.03 0.03
0.11 0.15
-0.12 -0.03
-0.14 0.00
-0.18 -0.09
-0.15 -0.07
0.00 0.00
-0.00 0.11
0.12 0.03
0.21 0.13
0° Free Field
Wind Screen Corrections
on 831C 0° with Wind
Free Field Screen on
831C1
dB dB
0.00 0.00
0.04 -0.04
0.09 -0.09
0.14 -0.14
0.09 -0.09
0.08 -0.08
0.00 0.00
0.11 -0.11
-0.09 0.09
-0.08 0.08
expanded
uncertainty
of
Corrections
'@ 95%
dB
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
0.25
B-1