Audio Spatial audio quiet when coming from the front

My project has a missile launcher that launches along the camera's forward. When a missile I launched impacts and I have not rotated the camera, i.e. the explosion is directly in front of the camera, the audio is very quiet. When I turn about 15 degrees it becomes loud like normal, but if i turn to look at it again it quiets down again.
Does anyone know what might cause this?
Thanks in advance!