Your little apple pie at this age is very alert about his surroundings. He can catch even the slightest of sounds made in the room. You as a parent need to make the baby familiar with voices and sounds. This will be a healthy developmental landmark for your little one.
What you need to know
Recognising voices happens around the fourth week post partum. His growth rate speeds up in the following months. You can call out to him from different directions and test if he responds. Make sure there is minimum disturbance in the room.You can also play music next to him and check his reaction, try playing different tunes.
This is a very good method to help sharpen his hearing abilities. Make sure you do not play music close by his ear; this could damage his ears and hinder auditory development.