Cockpit sound issue

[El Hadji]

I fly using TrackIR and I find it strange that the sound level and complexity of the sound varies depending on where I point my nose (MY nose, not the planes). If I look to the left or right the sound gets 'thinner' (lacking a better word) but if I continue to look towards the rear of the plane it gains in volume and complexity again. Surely, in a small cockpit strapped to a seat the noise level should be about the same regardless where I look, shouldn't it?