TESTO 815 Instruction Manual page 24

5. Operation
24
Setting the time weighting
The measurement time (time weighting) is set by pressing .
SLOW/FAST:
The ranges "Slow" with a time weighting of 1s and "Fast" with a
time weighting of 125ms are available. Incoming sound signals
are integrated in a time period from 1s or 125ms respectively.
When "Fast" is set, the display rate of a reading increases to
approx. 5-6 measurement rates per second. The "Slow" time
weighting is selected for noises whose signals only change slowly
e.g. machines, photocopiers, printers etc. Select the "Fast" mode
to measure sudden changes in sound level (e.g.building
machines).
Setting the frequency weighting
Frequency weighting is set with the button.
A/C:
The frequency weightings "A" and "C" are available. Frequency
weighting A is used for standard sound level measurements. This
weighting corresponds to the sound pressure felt by the human
ear, also referred to as "aurally compensated sound level". If the
low frequency levels of a sound are to be assessed, frequency
weighting C is used. If the displayed value is considerably higher
during the C weighting than during the A weighting, the level of
low frequency noise is high.