BSS Audio DPR-402 Owner's Manual - Manual (Page 25)

25
12.0 De-essing and Peak Limiting
In section 3 the problems with high frequency energy, also known as
sibilance, were discussed. The DPR-402 provides for this facility in either of
two distinct ways: Broadband de-essing and HF only de-essing.
Under program conditions, once the detector detects excessive amounts of
frequency, it will start to gain reduce the program level as in normal
compression. Because compression then occurs over the whole frequency
range of the program, it is called Broadband de-essing. To make the
compressor sensitive only to high frequencies, a high pass filter is inserted into
the CONTROL side chain insertion point, with the result that frequencies
below the filter cut-off point are excluded. Once excessive amounts of
frequency are detected compression will commence, but only on those high
frequencies program components that initially caused the compressor to act.
The type of de-essing to be used in a particular situation will depend largely
on the program type and whether the input to the compressor is a mix of
sibilant sounds and other program material, or exclusively the sibilant sound.
HF only de-essing will generally be used when processing a mix of program,
whereas broadband de-essing will be acceptable when processing only the
sibilant sound.
It should be realised that this technique is very different from simple
equalisation, since equalising a sibilant vocal by cutting high frequencies
would result in loss of high frequency content at all times. De-essing has no
effect whatsoever on the signal, except at the moment of sibilance, and then
the effect is only of overall level change. There is no change in the general
frequency response, yet sibilance is controlled.
12.1 De-essing
12.2 Broadband
De-essing and
controls
Broadband de-essing can be achieved either simultaneously with normal
compression on the same channel of the DPR-402, utilising DE-ESS and FREQ
controls (See figure 12.1a), or exclusively on the one channel by setting the
MODE switch to DE-ESS WIDE, and utilising the compressor section controls
(See figure 12.1b).
Fig 12.1a DE-ESS
Controls
De-essing and Peak Limiting