4
n
Caution:
For noise environments dominated by frequencies below 500 Hz the
C-weighted environmental noise level should be used.
LABORATORY ATTENUATION
MT17H682 Backband - Foam Cushions
Frequency (Hz)
125
250
500
1000
2000
3150
4000
6300
8000
NRR
CSA
Class
Mean Attenuation (dB)
15.5
17.9
26.0
31.3
32.4
38.9
41.3
44.7
46.2
Standard Deviation (dB)
4.0
2.5
2.3
2.7
3.2
3.2
3.0
3.8
4.4
22 dB
B
Frequency (Hz)
125
250
500
1000
2000
3150
4000
6300
8000
NRR
CSA
Class
Mean Attenuation (dB)
15.2
17.6
24.9
30.5
33.4
39.3
41.4
46.2
45.8
Standard Deviation (dB)
4.2
2.7
2.3
3.8
4.1
3.0
3.4
3.0
4.7
MT17H682 Backband - Gel Cushions
21 dB
B
Frequency (Hz)
125
250
500
1000
2000
3150
4000
6300
8000
NRR
CSA
Class
Mean Attenuation (dB)
13.6
17.7
28.8
31.9
32.3
39.3
39.9
42.1
41.4
Standard Deviation (dB)
2.6
2.5
2.7
1.9
1.5
4.1
2.3
2.6
2.5
MT17H682 Folding Band - Foam Cushions
23 dB
B
Frequency (Hz)
125
250
500
1000
2000
3150
4000
6300
8000
NRR
CSA
Class
Mean Attenuation (dB)
11.4
15.7
21.7
28.9
33.1
40.8
38.8
37.3
37.3
Standard Deviation (dB)
2.8
2.7
2.0
2.7
1.9
3.5
3.7
2.5
3.5
MT17H682 Folding Band - Gel Cushions
20 dB
B
Frequency (Hz)
125
250
500
1000
2000
3150
4000
6300
8000
NRR
CSA
Class
Mean Attenuation (dB)
15.1
20.3
26.4
32.1
33.0
39.7
34.1
39.4
40.1
Standard Deviation (dB)
3.9
2.7
3.0
2.8
3.5
3.7
3.5
2.9
2.3
MT17H682 Helmet Attachment - Foam Cushions *
22 dB
A
Frequency (Hz)
125
250
500
1000
2000
3150
4000
6300
8000
NRR
CSA
Class
Mean Attenuation (dB)
15.1
17.6
26.1
35.1
32.9
40.9
35.3
39.5
40.0
Standard Deviation (dB)
3.9
3.5
3.3
2.6
2.8
2.3
3.0
2.6
2.4
MT17H682 Helmet Attachment - Gel Cushions **
21 dB
A
* Tested with 3M™ Ceradyne™ Ballistic Helmet
** Tested with OPSCOR Helmet
