Human hearing range describes the range of frequencies that can be heard by humans. Accordingly humans can detect sounds in a frequency range from about 20 Hz to 20000 Hz. Humans are most sensitive to frequencies between 2,000 and 5,000 Hz. And also sounds we can’t hear that is below 20 Hz (Infra-sound) and above 20000 Hz (Ultrasound) can still hurt our ears. Therefore we can conclude that we can’t hear all the sounds of our surrounding.