BSS Audio OPAL Series DPR-944 Owner's Manual - Manual (Page 7)

7
Introduction
Note: For USA and Canadian users, the replacement fuse must be of an
identical UL rated type fuse for continued compliance with safety standards.
4.0 Introduction
The BSS Audio DPR 944 is a FOUR channel unit containing two channels of
ADVANCED GATING and two channels of PARAMETRIC COMPRESSION.
Both channels of the gate may be stereo linked, as can both channels of the
compressor. At all times the gate and compressor sections operate completely
independently. Each channel has separate balanced XLR input and output
connectors. As there are no obscure gate - compressor links to accidentally
activate during a live session, operating the unit is particularly
uncomplicated.
Gating
The gate section features the unique BSS characteristic audio level control
during both attack and release phases (refer to figures 7.3 - 7.5). This ensures
the most natural sounding operation, as the normal decay characteristic of the
signal is preserved. Special circuitry is provided to reduce the possibility of
false triggering and to ensure that it is possible to use a fast attack time
without running into the problem of ‘jittering’. The provision of fully
parametric key filtering and an external key input adds to the ease of use and
flexibility of the unit.
Parametric Compression
The compressor section uses the audibly transparent ‘subtractive VCA’
technology used in all other BSS compressors, and results in substantially
better performance than other methods. The subtractive VCA also allows the
realisation of a completely different type of compression that BSS have named
PARAMETRIC COMPRESSION. This allows you to selectively compress only
certain frequencies in a signal, as selected by two conventional looking
parametric filter controls on the front panel. When the selected frequencies
are encountered, the DPR 944 starts to compress only those signals at a rate
determined by the ratio and threshold controls. This is useful for controlling a
particularly strident vocalist or brass instrument for example. There are many
uses for this type of signal processing, and they are covered in section 11.0.
If desired, the parametric filter can be ‘dialled out’, in which case the DPR
944 compressors operate over the full frequency range.