There are many terms used in the discussion of aircraft noise. This section is designed to give you a broad overview of the most commonly used terms.
All sounds come from a sound source.
It takes energy to produce this sound, and this energy is transmitted through the air in sound waves, or tiny, quick oscillations of pressure just above and just below atmospheric pressure. These oscillations, or sound pressures, impinge on the ear, creating the sound we hear. This is the rate of repetition of the sound pressure oscillations as they reach our ear. Thus, the closer the vibrations, the higher the pitch and vice versa. Our ears are better equipped to hear mid and high frequencies than low frequencies, thus we find mid and high frequency noise to be more annoying.