The amount of time it takes for a sound wave to reach the brain is a changing value. The distance of the location from where the sound originates and the type of media the sound travels through are direct factors.
The speed of sound in air is different from the speed of sound in water. Speed travels more quickly in water than through air. A vibrating object is responsible for sending waves into the air or other media. The air begins to vibrate, and the waves of the vibration radiate outwards. The vibrating waves in the air reach the eardrum and travel to the brain.