User Manual
Table Of Contents
28
8:  SYBIL Evo 
VARIABLE FREQUENCY DE-ESSER
SYBIL Evo is a digital equivalent of a traditional 
vocal de-esser. When recording spoken or sung 
material, the sibilant sounds (Ss, Ts, CHs, and 
SHs) in the track sometimes (depending on the 
individual performer) appear louder than the rest 
of the signal. The effect can sound unnatural and 
often irritating. The solution to this problem is to 
compress only the sibilants, thereby lowering 
their level relative to the rest of the track. 
Processing a signal this way is called de-essing. 
The diagram below shows how a compressor 
and a high pass filter are traditionally configured to 
accomplish de-essing.
SYBIL Evo uses a digital algorithm to implement 
the de-esser function. While the details of the 
algorithm are quite complex, the resulting effect is 
functionally equivalent to the diagram above. 
COMPRESSOR
IN
IN OUT
OUT
SIDECHAIN 
INPUT
HIGH
PASS
FILTER










