DeEsser is a frequency-specific compressor, designed to compress a particular frequency band within a complex audio signal. It is used to eliminate hiss (also called sibilance) from the signal. The advantage of using DeEsser rather than an EQ to cut high frequencies is that it compresses the signal dynamically, rather than statically. This prevents the sound from becoming darker when no sibilance is present in the signal. DeEsser has extremely fast attack and release times.
When using DeEsser, you can set the frequency range being compressed (the Suppressor frequency) independently of the frequency range being analyzed (the Detector frequency). The two ranges can be compared in the DeEsser Detector and Suppressor frequency range displays. The Suppressor frequency range is reduced in level for as long as the Detector frequency threshold is exceeded.
DeEsser does not use a frequency-dividing network—a crossover utilizing lowpass and highpass filters. Rather, it isolates and subtracts the frequency band, resulting in no alteration of the phase curve.
The Detector parameters are on the left and the Suppressor parameters are on the right. The center section includes the Detector and Suppressor displays and the Smoothing slider.
Frequency knob and field: Set the frequency range for analysis.
Sensitivity knob and field: Set the degree of responsiveness to the input signal.
Monitor pop-up menu: Choose the signal you want to monitor and adjust.
Det(ector): Choose to monitor the isolated detector signal and to set the frequency range.
Sup(pressor): Choose to monitor the filtered suppressor signal and to set the frequency range.
Sens(itivity): Choose to remove the sound from the input signal in response to the Sensitivity parameter.
Off: Choose to hear the DeEsser output.
Detector Display: Shows the frequency range for detection.
Frequency knob and field: Set the frequency range for reduction.
Strength knob and field: Set the amount of gain reduction for signals that surround the specified frequency.
Activity LED: Indicates active suppression in real time.
Suppressor Display: Shows the frequency range for suppression.
Smoothing slider and field: Set the reaction speed for the gain reduction start and end phases. Smoothing controls both the attack and release times.