XO1 Operators Manual
Page 21
Parametric Equaliser Screen
To adjust parametric settings:
Use the ‘FREQ’ control for the frequency.
Use the ‘Q’ control for the Q.
Use the ‘GAIN’ control for the gain.
Each parametric section can be positioned at a frequency from 20Hz to 20kHz and
features a wide range of 'Q’s to produce response curves ranging from broad to
notch. The gain control ranges from +15dB to -30dB in 0.1dB steps. Frequency steps
are 1/36 octave resolution for precise control. Since all filtering is achieved in DSP all
settings are re-settable with absolute accuracy and in ganged mode parameters track
identically. Very narrow band notch filters (maximum ‘Q’ of 128) can be achieved and
unlike analogue filters these tight ‘Q’ filters are entirely stable. The maximum notch
depth is -30dB.
Parametric filters are carefully implemented using Double Precision processing. This
method is costly in terms of processing power but yields substantial benefits in terms
of the XO1's exceptional noise performance and greatly improved low frequency
stability.
(Note: To show parametric filters in bandwidth (BW) rather than ‘Q’, go into the
‘System sub-menu’, select ’filter Q or BW’, select BW.)
To switch a filter from parametric mode to shelving mode, set the gain of the filter to
0dB and then turn the ‘Q’ control anti-clockwise until ‘HiSHF’ or ‘LoSHF’ is displayed.
Now set the frequency and gain as required. To set the filter back to a parametric
section, just ensure that the gain is at 0dB, otherwise the ‘Q’ control will have no
effect.
