This trace actually represents about 2½ minutes of data, but,
for the purposes of this section, it could represent 2½ hours or 2½ seconds; the
points made would still be equally valid.
You can see that within a very short
period of time the level varies by some 15 dBA. For single, short, events
it may be acceptable to represent them by the maximum reading on the meter (Lmax);
for example, gunshots are often represented by the LAmax "Fast", also
noise limits use Lmax "Peak" and
represents nighttime events in terms of LAmax
for longer periods (say greater than a few seconds) we
need to use something more complex; simply using the
maximum level of even reporting the range of values isn't
descriptive enough; we want to represent a complete
noise environment and some form of global analysis of the noise is required.
This is why statistical analysis and energy averaging are