the sounds we hear are regardless of sounding outside or inside are all inside. think of it like this..computers come with an option of 3d sound, where speakers can take a certain signal and make it sound like its all around you.

the same is happening with our ear/brain, these sounds can simulate coming from behind walls, or from another room. the way to test it is to make a bath, and submerge your ears, and try to test the voices to say something while submerged. You will hear them clearly, unlike the real sounds from a tv or people.

the fact that this is possible for me at least points to an intelligence and intent.