When comparing the noise attenuation level between the David Clark H10-56 and helmets I noticed that the noise attenuation for frequencies up to about 4000 Hz is actually better on the headset but better on helmets for higher frequencies. Are passive helmets still preferred if you want good noise attenuation compared to passive headsets for turbine and/or piston helicopters?
Is there any passive headset that has better noise attenuation than the David Clark H10-56? Does the K10 helmet kit offer any reduction in noise level?