Rangerwalker71
New member
I recently picked up a B&K 2209 Meter.
This is used in Mil-Spec standard testing for Sound reduction.
Standards are:
testing in accordance with MIL-STD-1474D using calibrated military-approved equipment and provide these or unweighted results. Measurement equipment includes calibrated Brüel & Kjær model 2209 Impulse Precision Sound Level Meter with 20 μs rise time using GRAS pressure measurement microphone model 40BP (Bruel & Kjaer model 4136 equivalent) while positioned one meter left and level with muzzle, oriented upward, and 1.6 meters above dirt/grass. Digital samples are taken from AC output signal path by M-Audio Solo at 10.4 μs intervals (96,000 per second) and 24 bit resolution (16.7 million possible steps). Recording hardware rise-time has been estimated at (using the 0.35/BW formula) 8.75 microseconds while the microphone is estimated to have a rise-time of 5.0 microseconds. Total system calibration during each use with Brüel & Kjær model 4220 Pistonphone. Sound analysis is linear to better correlate with perception. Linear measurement results in higher levels than ‘A’ weighing and this data should not be compared to MIL-STD data. Temperature and humidity measurements by Kestrel meters. Silencers will be examined for evidence of artificial environments. If present, this will be noted unless the medium can be removed.
I only did 5 shot averages not 10 to conserve ammo, I have a lot of testing to do.
Here are some of the numbers for the SAS Barricade.
.260 REM 24" barrel Unsuppressed Ave. 168.5 DB
Suppressed average 141.1DB
Suppressed level at shooters ear. 127.8DB
Barricade on a 556 16" AR. 138DB
Hope this helps. Will be posting several more as i get them.
This is used in Mil-Spec standard testing for Sound reduction.
Standards are:
testing in accordance with MIL-STD-1474D using calibrated military-approved equipment and provide these or unweighted results. Measurement equipment includes calibrated Brüel & Kjær model 2209 Impulse Precision Sound Level Meter with 20 μs rise time using GRAS pressure measurement microphone model 40BP (Bruel & Kjaer model 4136 equivalent) while positioned one meter left and level with muzzle, oriented upward, and 1.6 meters above dirt/grass. Digital samples are taken from AC output signal path by M-Audio Solo at 10.4 μs intervals (96,000 per second) and 24 bit resolution (16.7 million possible steps). Recording hardware rise-time has been estimated at (using the 0.35/BW formula) 8.75 microseconds while the microphone is estimated to have a rise-time of 5.0 microseconds. Total system calibration during each use with Brüel & Kjær model 4220 Pistonphone. Sound analysis is linear to better correlate with perception. Linear measurement results in higher levels than ‘A’ weighing and this data should not be compared to MIL-STD data. Temperature and humidity measurements by Kestrel meters. Silencers will be examined for evidence of artificial environments. If present, this will be noted unless the medium can be removed.
I only did 5 shot averages not 10 to conserve ammo, I have a lot of testing to do.
Here are some of the numbers for the SAS Barricade.
.260 REM 24" barrel Unsuppressed Ave. 168.5 DB
Suppressed average 141.1DB
Suppressed level at shooters ear. 127.8DB
Barricade on a 556 16" AR. 138DB
Hope this helps. Will be posting several more as i get them.
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