ABSTRACT
The level recorder is an instrument in use for nearly all forms of sound analysis. The displaying of level can be done either by plotting the level along a time axis or by performing a statistical analysis that shows the level distribution over an interval of time. In connection with noise measurements or measurements such as the calculation of the Loudness Range, a statistical analysis is applied that provides the cumulative distribution of the sound levels recorded. In the graphical rendering, a graph is shown where one axis is the A-weighted sound pressure level while the other axis represents the percentage share of the time interval under consideration. The curve shows which sound pressure level exceeded for what percentage of the time. The concept of background noise in the external environment typically is defined as the A-weighted sound pressure level that is exceeded during 95% of the time interval observed.
