Question

what help us judge direction of sound

Answer 1

If a sound comes in at an angle to the right of the face, the direction of the sound waves means that the sound will not reach both ears at the same time. The time lag is due to the fact that the distance from the source of the sound to the left ear is a little longer than it is to the right ear.

Answer 2

Answer: The sensation of the sound comes from our ability to distinguish the source of the sound based on the variation in  the volume of the sound perceived between both the ears.

Explanation:

see the video here that explains visually as well.