11
5
NOISE CRITERION CURVES
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 (0dB=0.0002 µbar)
BAND CENTER FREQUENCIES, Hz
PKA-A12HA6
PKA-A18HA6
High
NOTCH
Low
43
SPL(dB)
36
LINE
UNIT
WALL
3.3ft
3.3ft
MICROPHONE
OCH580
