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Chapter 4 Dynamic 47
DeEsser
A DeEsser is a signal processor used for the rejection of hissing, or sibilant noises. This is
why it is called a “DeEsser”, and occasionally an “S”-Suppressor. You can, of course, reject
sizzling frequencies with an equalizer, but a DeEsser only rejects this high frequency
band for as long as a threshold level is being exceeded in a specific frequency band.
This “dynamic” ability is why the sound doesn’t get darker when no “sizzling”
consonants are present in the signal. A DeEsser is a frequency-specific compressor,
designed to only compress a particular frequency band within a complex full band
signal. It features extremely fast attack and release times.
In the Logic DeEsser, the dynamic rejection does not necessarily need to take place in
the same frequency range that’s being analyzed. Rather, the DeEsser performs a gain
reduction in the frequency band displayed in the lower window for as long as the level
exceeds a threshold (which falls within the frequency range) displayed in the upper
window.
Note: Please don’t confuse a DeEsser with an effect known as a “Vocal Stressor”. The
latter reduces the gain of the entire range when the level exceeds a threshold defined
in a given frequency range. This type of processing can be achieved with any
compressor with a high pass filter or EQ inserted in its side chain.
The Logic DeEsser does not make use of a frequency dividing network (a crossover,
utilizing low and high pass filters). Rather, it is based on a subtraction of the isolated
frequency band, leaving the phase-curve untouched.
The DeEsser is especially important in FM radio applications, because sharp S-type
consonants can cause harsh intermodulation distortion noises. The need for this
depends very much on the language spoken: English has fewer of these consonants
than German or Spanish, for example.