106
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
OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
μ
bar)
OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
μ
bar)
OCTAVE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
μ
bar)
BAND CENTER FREQUENCIES, Hz
NOTCH
High
Medium1
Medium2
Low
SPL(dB)
40
37
34
32
LINE
NOTCH
High
Medium1
Medium2
Low
SPL(dB)
40
37
35
33
LINE
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
BAND CENTER FREQUENCIES, Hz
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
BAND CENTER FREQUENCIES, Hz
NOTCH
High
Medium1
Medium2
Low
SPL(dB)
41
39
37
35
LINE
A
K
0
6
P
R
-
A
C
P
A
K
0
5
P
R
-
A
C
P
PCA-RP71KA
1m
1m
unit
about 1.4m
MICROPHONE
ceiling