12
1
1
90
80
70
60
50
40
30
20
10
63
125
250
500
1000
2000
4000
8000
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCT
AVE BAND SOUND PRESSURE LEVEL, dB re 0.002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
PKH-1.6/2GKL
PKH-1.6/2GKLH
Hi
NOTCH
Lo
43
SPL(dB)
36
LINE
6. NOISE CRITERION CURVES
UNIT
WALL
1m
1m
MICROPHONE
Ambient temperature 27
Test conditions are based on JIS Z8731
OC229A
