What it does
Audio dynamic range limiter built from basic elements.
A measurement of peak audio amplitude is used to generate a gain-reduction control signal (in red) which is multiplied by the input, thus limiting the output amplitude below the user-defined threshold. The logarithm block is required to convert the peak measurement to dB. The control limiter block compares the measured peak (in dB) with the user-defined dB threshold (slider in the Limiter Threshold bock), and generates a gain-reduction signal if the peak exceeds the threshold. The antillog of the control signal is taken (to convert back from dB). This signal is then smoothed and multiplied by a delayed version of the input audio signal, thus limiting the amplitude of the output audio signal. The delay gives the system a predictive ("look-ahead") capability. Experiment with the slider settings of all blocks to explore the behaviour of the limiter.