20
90
80
70
60
50
40
30
20
10
63
125
250
500
1000
2000
4000
8000
APPROXIMATE
TERESHOLD 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 re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
PCA-P3HA
NOTCH
Hi
Lo
SPL(dB)
38
34
LINE
90
80
70
60
50
40
30
20
10
63
125
250
500
1000
2000
4000
8000
APPROXIMATE
TERESHOLD 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 re 0.0002 MICRO BAR
BAND CENTER FREQUENCIES, Hz
PCA-P5HA
NOTCH
Hi
Lo
SPL(dB)
50
44
LINE
5. NOISE CRITERION CURVES
1m
1m
unit
about 1.4m
MICROPHONE
ceiling
OC289--1.qxp 03.3.19 10:50 AM Page 20
