Cobalt Digital COMPASS 9086 Embedded Audio Loudness Processor - Manual (Page 75)

9086-OM (V4.3) 9086-SD PRODUCT MANUAL A-7
Appendix A
Measurement Techniques For Various Program Material Forms
Modifying LKFS Assessments Using Parametric Settings
Measurement Window Setting. (See Figure A-3.) The Measurement
Window parameter sets the sampling time accumulated in each averaging
recalculation. As such, longer periods will include more short-term LKFS
“look-back” values into the moving average. Because the Measurement
Window setting affects averaging that is used in measuring and calculating
the LKFS measurement, changes in this setting will affect LKFS
measurement.
Figure A-3 Modifying the Measurement Window Parameter
Long-Form Simplified Measurement. (See Figure A-4.) Post-production
long-form material can in many instances be easily assessed by applying a
rather long
Measurement Window (in this example, 10 seconds). In this
manner, the typically brief loudness variations in professionally produced
material (or breaks between material) will not result in nuisance errors.
However, if the material exhibits a consistent gross deviation from the
selected target LKFS or dialnorm (for example, due to level imbalance
between a network feed and local insertion), the averaging period is
conversely likely to be sufficiently short as to show a level-triggered error
somewhere over the course of the offending material.
Shorter Measurement Window produces more
responsive averaged LKFS reading, with greater
range variation over the course of sampling.
Longer Measurement Window produces a more
representative averaged LKFS reading over the
course of sampling, with reduced sensitivity to
short-term LKFS deviations.
t
Program Material short-term LKFS
LKF
S