Svantek SVAN 971 - Page 147

SVAN 971 User Manual – Appendixes
147
Time weighting characteristics (Exponential averaging)
Slow “S“ according to IEC 61672 Class 1, Equivalent Time Constant 1000 ms
Fast “F” according to IEC 61672 Class 1, Equivalent Time Constant 125 ms
Impulse “I” according to IEC 60804 Class 1, Equivalent Time Constant 35 ms, Hold Time 1500 s
Reference conditions
• Class of the acoustic field Free field
• Reference acoustic pressure 114.0 dB (related to 20 Pa)
• Reference frequency 1000 Hz
• Reference temperature +20°C
• Reference relative humidity 65 %
• Reference static pressure 1013 hPa
• Reference incidence direction perpendicular to the microphone diaphragm.
Calibration
Acoustical - with the SV 30A acoustic calibrator (or equivalent):
• Calibration level for the free field 113.87 dB (see A.C.O. 7052E free field correction table below)
• Calibration level for the diffuse field 114.0 dB (see A.C.O. 7052E free field correction table below)
Microphone
ACO 7052E prepolarized free-field ½” condenser microphone
Nominal sensitivity 35 mV/Pa (corresponding to -29 dBV/Pa re 1 V/Pa)
Capacitance 17 pF.
Note: Maximum level of sound pressure level, which can be affect the microphone without
destruction the microphone: 155 dB.
Table C.1.6. ACO 7052E free field correction for electrostatic actuator the 0 deg incidence
Correction
factors
[dB]
Frequency [Hz]
20
25
31,5
40
50
63
80
100
125
160
200
250
315
400
500
630
800
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.06
0.07
Frequency [Hz]
1000
1250
1600
2000
2500
3150
4000
5000
6300
8000
10000
12500
16000
20000
0.1
0.13
0.24
0.34
0.48
0.72
1.1
1.55
2.24
3.06
4.37
5.94
7.86
10.57
Table C.1.7. ACO 7052E free field correction for B&K 4226 calibrator for the 0 deg incidence
Correction factors
[dB]
Frequency [Hz]
250
500
1000
2000
4000
0.0
0.06
0.13
0.58
1.65
Frequency [Hz]
8000
12500
16000
20000
4.24
7.29
9.17
10.95