Lowest detectable pitch

The intensity of noise or sound is measured in terms of pressure. The pressure of the quietest sound that can be detected by a person of normal hearing at the most sensitive frequency of c. 2,750 Hz is 2 x 10-5** pascal. One-tenth of the logarithm to this standard provides a unit termed a decibel (dBA). prolonged noise above 150 decibels will cause immediate permanent deaf-ness, while above 192 dBA a fatal over-pressure shock-wave can be formed. A noise of 30 dBA is negligible. ** -5 should be in superscript (i.e to the power of minus 5)** ** -5 should be in superscript (i.e to the power of minus 5)**