According to a study compiled by
Chris Gilbert (MIOA) and Simon
Bull (MIOA), 90% of all
environmental noise measurement
tasks can be completed using only
three measurement parameters; LAeq
(Equivalent Sound Level), L90
(Sound level exceeded for 90% of the
time) and LAmax (Maximum Sound
Pressure Level).

With this in mind, the SONUS E
sound meter from Castle Group has
been designed for straightforward
operation. It has a single lead-acid
battery lasting over a week and a total
system weight of less than 5.5kg.

The SONUS E will measure down
to 22dB and will give 2 parallel
measurements, which is required in
some environmental standards. The
parameters measured include Leq, LE,
Lmax, L10, L90 and one user defined
Ln value and the data-logging is
capable of taking a measurement
every second as well as overall levels.