Some observations about the different measurements
used in community noise. For the last 40 years, measurements of facilities have been either A-weighted or in bands:
octave or ⅓-octave. These measurements were originally
limited by the technology available in the instrumentation.
The A-weighted curve approximates the human ear’s
response at 40 dB over the audible frequency range. Sounds
heard are not “masked” unless the sounds fall within the
ear’s critical bands. Those bands are on the order of the ⅓-octave. Therefore, unless the intruding sounds are in the
same critical bands as the background sounds, the facility
will be heard