The RWR warning in FC3 aircraft, for example, can be adjusted in real time in game. Other warnings are inside the cockpit and are audible and adjusted with the In-Cockpit volume.
HELMET volume is both the Radio chatter and the Warnings on those aircraft that have them into the headset of the pilot. However, the volume sliders dont have to be at 100%.
I sense some frustration in your posts and its understandable. Trust me, there's nothing wrong with DCS sounds in any module.