Sound Level Meter

Figure 7. We can analyze sounds, showing how the energy is distributed over different frequency bands, by means of a Sound Level Meter (sLM).

Such an analysis is made by means of a Sound Level Meter.

This is a piece of hand-held equipment containing:

• a microphone (to convert the sound wave into an electrical signal);
• an amplifier (to increase the strength of the signal);
• a set of filters (to select different ranges of frequencies for measurement); and
• a meter (or digital read-out device) to indicate the sound pressure level being measured.

If all the filters are switched out, the meter reads the total energy of the noise at all frequencies. If only one of the filters is switched in, the meter responds only to the energy in the band of frequencies passed by the filter .