ABSTRACT
In many cities today, there are local ordinances specifying maximum allowable sound levels at commercial and residential property lines. The main quantity used to describe sound is the size or amplitude of the pressure fluctuations at a human ear. A healthy human ear of a young person can hear frequencies ranging from 20 Hz to 20 kHz. In terms of sound pressure level, audible sounds range from the threshold of hearing at 0 dB to the threshold of pain, which can be over 130 dB. Sound level of a source can be measured by directly measuring sound pressure or sound intensity at a known distance. Both of these measurement techniques are quite equivalent and acceptable. A sound-level meter is an instrument designed to respond to sound in approximately the same way as human ear and to give objective, reproducible measurements of sound pressure level. Sound intensity measurements are directional in nature and only measure sound energy radiated form sound source.
