Page 76
APA-4E8 Operator’s Manual
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Low/High Pass Variable ‘Q’ Filter
(Low Pass shown)
The low and high pass variable ‘Q’
filters have adjustable frequency and
‘Q’ (or Bandwidth) controls. The ‘Q’
control adjust the damping of the filter,
so that low ‘Q’ settings show less
overshoot at the turnover frequency,
but also slower roll-off.
Remember that ‘Q’ is 1/Bandwidth, so
the higher the ‘Q’, the lower the
Bandwidth, and the smaller the range
of frequencies affected.
The filter is primarily 12dB/Octave, but in achieving this sort of roll-off with a high ‘Q’ value
will result in quite a large overshoot in level at the turnover frequency. This type of filter is
often also called a resonant filter.
