SPH-4 Flyer's helmet and Single-flange earplug		
"USAARL Report No. 93-10, Jan 1993"		
Freq(Khz) Mean_Gain(dB) StDev_Gain(dB) Note: -10dB Gain = 10dB Attenuation		
0.0625	-18.6	1.5
0.125	-27.5	4.9
0.25	-29.5	5.5
0.5	-34.4	6
1	-32.1	5.5
2	-38.3	4.4
4	-49.6	5
8	-55.3	5.5
