8
5NOISE CRITERION CURVES

UNIT

WALL

3.3ft

3.3ft

MICROPHONE

90
80
70
60
50
40
30
20
10
63 125 250 500 1000 2000 4000 8000
NC-60
NC-50
NC-40
NC-30
NC-20
NC-70
OCTAVE BAND SOUND PRESSURE LEVEL, dB (0dB= 0.0002 μ
bar
)
BAND CENTER FREQUENCIES, Hz
APPROXIMATE
THRESHOLD OF
HEARING FOR
CONTINUOUS
NOISE
High
NOTCH
Low
49
SPL(dB)
43
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
OCTAVE BAND SOUND PRESSURE LEVEL, dB(0dB=0.0002 μbar)
BAND CENTER FREQUENCIES, Hz

PKA-A24KA

PKA-A30KA

PKA-A24KAL

PKA-A30KAL

High
Low
45
SPL(dB)
39
LINE
NOTCH PKA-A36KA4.THPKA-A24KA4.TH

PKA-A30KA4.TH