The sound is "received" by your outer ear and then travels along the outer ear canal until it reaches the eardrum. This vibrates when the sound waves hit it. Pressing on the other side of the eardrum are the middle ear bones.
These bones act like a series of levers, magnifying the movement produced by the eardrum until the final bone, the stirrup bone starts vibrating.
The stirrup bone transmits the vibrations to the inner ear – a hollow organ filled with liquid and with the inside covered in fine hairs.
These hairs are sensitive to movement and convert it to a series of electrical impulses. These signals are then carried by the nerve to the brain.