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407750-EN v2.2 07/13
7
Reference Information
Frequency Weighting Characteristics
Frequency (Hz) A Weighting C Weighting Tolerance (IEC 651 Type 2)
31.5 -39.4dB -3dB ±3dB
63 -26.2dB -0.8dB ±2dB
125 -16.1dB -0.2dB ±1.5dB
250 -8.6dB 0dB ±1.5dB
500 -3.2dB 0dB ±1.5dB
1 k 0dB 0dB ±1.5dB
2 k +1.2dB -0.2dB ±2dB
4 k +1dB -0.8dB ±3dB
8 k -1.1dB -3dB ±5dB
Typical A-Weighted Sound Levels
50HP Siren (100')
130
120
110
100
90
80
70
60
50
40
30
20
10
140
0
Jet takeoff (200')
dB
Riveting machine
Chain saw
Subway (20')
Boiler room
Pneumatic drill (50')
Freight train (100')
Vacuum cleaner (10')
Speech (1')
Large store
Large Office
Small office
Residence
Night residential area
Whisper (5'0)
Sound studio
Threshold of hearing