Cats hear the same way that humans do, by processing sounds through their ear canals. Their ears are much more sensitive than humans and most animals.
The cat ear is designed to hear a multitude of sounds. Because of the open design and the ability to move them nearly 180 degrees, a cat has a superior ability to hear sounds, even those that are quite far away. For instance, a cat is able to hear a mouse rustling in brush about 30 feet away.
A cat's hearing range is between 45 to 64,000 in hertz, compared to a human's hearing range of 64 to 23,000. The significant difference on both ends of the spectrum means that they can hear sounds that aren't detectable by the human ear.