In other words, frequency is the number of times per second that a vibrating body completes one cycle of motion. Low pitched or bass sounds have low frequencies. High-pitched or treble sounds have high frequencies. A healthy, young person can hear sounds with frequencies from roughly 20 to 20,000 Hz. The sound of human speech is mainly in the range 300 to 3,000 Hz.
Sound pressure is the amount of air pressure fluctuation a noise source creates.
If the drum is hit harder, its surface moves farther from its rest position. As a result, the pressure increase is greater. To the listener, the sound is louder. Sound pressure also depends on the environment in which the source is located and the listener's distance from the source. The sound produced by the drum is louder two metres from the drum if it is in a small bathroom, than if it is struck in the middle of a football field.