Operator’s Manual
DC1048 Integrated Audio Management
Page 51
Shelving EQ (High Shelf shown)
The shelving EQ has adjustable
frequency, ‘Q’ (or Bandwidth) and
Gain controls. These affect a
range of frequencies from the
turnover freqency as shown in the
graph. For a high shelf,
frequencies above the turnover
frequency will be affected. For a
low shelf, frequencies below the
turnover frequency will be
affected.
Various levels of cut and boost
are shown to the left, along with
various ‘Q’ settings (gain boosts
only are show below).
Remember that ‘Q’ is 1/Bandwidth, so the
higher the ‘Q’, the lower the Bandwidth,
and the smaller the range of frequencies
affected.
Note that ‘Q’ settings above 0.75 will
result in slight overshoot in the filter
response (as seen at the highest setting
to the right). This is normal behaviour
and does not indicate instability.
Creating a Flat
-
topped EQ Response
Use two EQ bands, BOTH
configured as low shelves. For an
overall BOOST, set the
Lower
frequency filter to
BOOST
the
desired amount, and the
Upper
frequency filter to
CUT
by the
same amount.
This example shows one filter at
100Hz and the other at 2kHz,
with the 100Hz filter at –10dB,
and the 2kHz filter at +10dB.
Varying the ‘Q’ affects the slope –
values above 0.75 cause
overshoot as shown. Assymetrical responses may be achieved by adjusting the
‘Q’ of each filter independantly.