12
NOISE CRITERION CURVES
5
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
OCT
A
VE BAND SOUND PRESSURE LEVEL, dB (0 dB
0.0002
bar)
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
OCT
A
VE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
μ
bar)
NOTCH
High
Medium1
Medium2
Low
SPL(dB)
41
39
37
35
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
OCT
A
VE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
μ
bar)
NOTCH
High
Medium1
Medium2
Low
SPL(dB)
43
41
39
37
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
OCT
A
VE BAND SOUND PRESSURE LEVEL, dB (0 dB = 0.0002
μ
bar)
NOTCH
High
Medium1
Medium2
Low
SPL(dB)
45
43
41
39
LINE
3.3 ft
3.3 ft
Main unit
about 4.62 ft
MICROPHONE
ceiling
PCA-A24KA7.TH
PCA-A30KA7.TH
PCA-A36KA7.TH
PCA-A42KA7.TH
OCH638