The Direction of Sound
When someone calls your name from across a room, you can instantly tell where the person calling you is, right? It is pretty important to know where a car is coming from before you cross the road! Some owls has ear that are located on the head asymmetrically. This makes it easier from them to detect from where a small animal is located. So this brings about the question: How do we know where things are, by hearing them? There are three main factors that help us determine where sound is coming from: Timing, volume and tone.
Time lag
This is the very small difference in time from when the sound hits the left ear and the right ear. This is due to the space/time difference between the two ears. Our brain can use this information to work out where the sound is coming from. An example: When someone is standing to the right of you and calls you, your right ear will hear it slightly before the left. Although this time difference is so small that we don’t notice it, our brain does, and tells us that the person is to our right.
Volume
The volume of the sound helps us determine how far away a something is, and it can also help determine the direction of the sound too. This is because the sound is very slightly quieter in one ear than the other due to the distance between them and because of object between the ears… Your head. Your head absorbs some sound making it slightly quieter when it hits the the other ear. An example: When our friend speaks to us from the right, our right ear hears the sound slightly louder than the left. Again, we don’t really notice this difference, but our brain does.
Tone
The tone of a sound also helps the brain figure out where it’s coming from. Generally, the further away a sound is, the less high frequencies there are. This is because the bass energy travels further than high frequencies and the objects around absorb more high frequencies than low frequencies. An example: When you’re standing far away from a concert or music festival, all you really hear is the bass. This is an extreme example because we’re standing very far away, but it’s the same concept.
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