The input channels, *x*, pass through a K-weighted
filter implemented using the algorithm of the Weighting
Filter block. The K-weighted filter shapes the frequency spectrum
to reflect perceived loudness.

#### Momentary Loudness

The K-weighted channels, *y*, are
divided into 0.4-second segments with 0.3-second overlap. If the required
number of samples have not been collected yet, the Loudness
Meter block returns the last computed value for momentary
loudness. If enough samples have been collected, then the power (mean
square) of each segment of the K-weighted channels is calculated:

The momentary loudness, *mL*, is
computed for each segment:

*mL* is the momentary loudness returned
by your Loudness Meter block.

#### Short-Term Loudness

The K-weighted channels, *y*, are
divided into 3-second segments with 2.9-second overlap. If the required
number of samples have not been collected yet, the Loudness
Meter block returns the last computed values for short-term
loudness and loudness range. If enough samples have been collected,
then the power (mean square) of each K-weighted channel is calculated:

The short-term loudness, *sL*, is
computed for each segment:

*sL* is the short-term loudness returned
by your Loudness Meter block.