Drawmer DC2476 Digital Mastering Processor - Manual (Page 22)

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CHAPTER 4
BASIC EFFECTS
The signal chain comprises six blocks in addition to the Input and Output
sections, which are addressed in exactly the same way as the effects blocks.
The DQ and Equaliser blocks are of necessity full-band (they affect the
entire signal), while the Expander, Compressor, Limiter and Tube Drive
sections that follow are all three-band. Three-band processing enables more
processing to be applied without introducing unwanted side effects, and
also allows for creative processing that alters the overall spectral balance of
the signal.
INPUT PAGE
The input page shows the signals as a graphic display of the signal level
passing to the effects functions. A dotted line at the top of each display
shows the maximum signal level. Use the control knob to adjust input levels.
Push the knob to select Left/Right/Both, then turn to adjust.
The internal > gain management = will reduce gain if signal peaks are too
high and would otherwise cause distortion. This is shown on the input screen
GR meter (see diagram). Adjust gain so that the GR meter shows minimum
activity, responding only to the signal highest peaks.
DYNAMIC EQ AND FULL BAND COMPRESSOR
A high performance floating threshold dynamic equaliser consists of a single
band parametric EQ with up to 12dB Boost or Cut, under dynamic control.
Frequency is adjustable from 64Hz to 8kHz in semitone increments with
bandwidths from 0.25 to 3 octave. This is shown graphically on the LCD
screen as a familiar EQ curve. Dynamic gain (DGAIN) is variable from -12dB
to +12dB. Positive values produce enhancement of the selected frequency
band, whilst negative values produce a reduction. Negative values may be
used for frequency-selective de-essing or de-popping while positive values
‘expand’ the selected frequency range, making it more prominent.
Because the process is dynamic, low level signals will not be treated, and
when enhancing low frequencies to add punch to a mix, this can help avoid
muddying the mid range while keeping the bass sound tighter than trying to
do the same thing with conventional EQ. Selecting ‘Filter’ puts the DC2476
into filter listen mode so that filter characteristics may easily be evaluated.
Pushing the knob when adjusting Frequency or Bandwidth selects output as
Normal or Filter. Selecting Filter enables the filtered signal to be monitored
without processing. This helps in locating the exact frequency to be processed
by the Dynamic EQ and is of particular value when using negative DGAIN
values.Normal is auto selected when other parameters are selected or when
leaving the Dynamic EQ block.
Though the DC2476 includes a three-band compressor, it can sometimes
be useful to apply a degree of compression prior to equalisation. For this
reason, the DQ section also includes a full-band compressor. Like the later
three-band compressor, this has a bootstrap characteristic where the level
of low level signals is increased rather than high level signals being
decreased. The position of the dotted line across the display window shows
by how much low level signals have been increased.
The compressor section has three controls. COMP adjusts the amount of
compression and has a range from
- 24dB to +24dB. Positive values compress
the full band signal whilst negative values are used to de-compress or expand
material which is already over compressed. Attack and Release controls are
semi-automatic, programme adaptive, providing a wide range of user control
and at the same time taking account of the dynamics of the signal. The
dotted line across the graphic display indicates the amount of compression
(i.e. the amount of gain applied at low levels). A GR bar display to the right of
the screen and connected to the dotted line indicates gain reduction. This
shows the gain being reduced back to 0dB in response to high level signals.
Conversely, when COMP is set to a negative value, the dotted line shows
the attenuation applied to low level signals, with the bar meter showing rises
in gain towards 0dB as the signal increases in level. Positive Dynamic EQ
(DGAIN) and Compressor (COMP) settings can produce signals which could
cause overload. The Gain Management will reduce the signal level when
this occurs. This is shown on the on screen GR meter and is also affected
by any boost applied by the EQ section.
See EQ GAIN MANAGEMENT below.