Microphone_HandbookMicr ophone Handbook Test and Measur ement Micr ophones Intr oduction Pressure variations, whether in air, water or other mediums, which the human ear can detect, are considered sounds. Acoustics is the science or the study of sound. Sound can be generally pleasing to the ear, as in music, or undesirable, referred to as noise. The typical audible range of a healthy human ear is 20 to 20,000 Hz. A Sound Pressure Level (SPL) beyond the detectable frequencies of the human ear can also be very important to design engineers. Noise, Vibration and Harshness (NVH) is concerned with the study of vibration and audible sounds. Vibrations represent a rapid linear motion of a particle or of an elastic solid about an equilibrium position, or fluctuation of pressure level. Harshness refers to the treatme……