Honda G100K2 Applications Manual page 36

METHODS OF MEASURING SOUNDS
The sensitivity of the human hearing sense varies by the frequency. For this reason, a sound level meter has
switches for selecting frequency compensation characteristics patterns (A, B, C, F) so that sensitivity to sounds
may be varied freely.
A characteristics
In A characteristics, measured sounds are
compensated in such a way that the result is the
closest to the human hearing sense.
This type of characteristics are used commonly
for measuring noises associated with
automobiles and machines.
Measured values are indicated by dB (A).
RELATIONSHIP TO THE NUMBER OF SOUND SOURCES
1. When the number of sound sources doubles, the level increases by 3 dB.
When there are two identical sound sources (60 dB each), the resultant level is 63 dB and not 120 dB.
2. When the number of sound sources is increased ten times, the level is 70 dB rather than 600 dB.
By a normal human ear, the combined sound is felt as it is twice as large the original sound.
60 dB
63 dB
70 dB
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NOISE