you just answered why you can't hear anything outside the cockpit with that 2000 HP engine screaming in front of you.
the air around and in your ears is already vibrating so much anything beyond your enclosed cockpit has to travel through the air outside the plane, through the canopy into an airspace that is so insanely disturbed by all the vibration within the aircraft that distant sounds get lost and become indestinguishable.
and you are waering ear protection for gods sakes.