I have many thousands of hours on Chinook without any hearing loss whatsoever. I use the unaugmented Mk 4 helmet and each time I plug in, I have to turn down the previous occupant's intercom and radio volumes. Everyone seems to use CEP or VAMPS and I wonder if these devices, while cutting out background noise, force aircrew to turn up their volume controls and thus receive a higher peak volume at their ear. Will there be any long-term effect on their hearing as a result of this higher peak volume?