Using Filters - Korg microX Operation Manual

Using Filters

The filters allows you to diminish or emphasize
specified frequency areas of the sound.
The tone of the sound will depend significantly
on the filter settings.
microX provides Filter1 for OSC1 and Filter2 for
OSC2. For each of these filters, you can select from
two types (Low Pass Resonance or Low Pass &
High Pass). Filter2 can be used if "Mode (Oscilla-
tor Mode)" is set to Double.
Level
Filter characteristics
Level
Filter Types
This selects the parts of the sound which will be
affected by the filter, as described below.
Low pass filter
This is the most common type of filter, which
passes the low frequency range and cuts the high
frequency range. When the overtones of the high
range are cut, a bright sound will become darker
(more mellow).
24 dB/oct and 12 dB/oct see the steepness of the
cut. 24 dB/oct means that the gain will decrease 24
dB in one octave (i.e., as the frequency doubles). A
12 dB/oct filter would decrease the gain 12 dB in
one octave. The 24 dB/oct filter produces a steeper
cut.
Low Pass
Level
Overtones included
in the original multi-
sample
Frequency (pitch)
Filter
This area of overtones
will be diminished
Overtones after
passing through
the filter
Frequency (pitch)
12dB/oct
24dB/oct
Frequency
High pass filter
This type of filter passes the high frequency range
and cuts the low frequency range. Use this when
you wish to make the sound thinner. However if
the cutoff frequency (Frequency) is raised exces-
sively high, the volume will become very low.
High Pass
Level
Resonance
When "Resonance" is set to a higher value, the
overtones in the region of the cutoff frequency will
be boosted as shown in the diagram below, giving
a distinctive character to the sound.
When resonance is applied
Low Pass
Level
Low resonance
value
When this is set to 0, there is no emphasis, and fre-
quencies beyond the cutoff will simply diminish
smoothly.
At medium settings, the resonance will alter the
timbre of the filter, making it sound more nasal, or
more extreme. At very high settings, the resonance
can be heard as a separate, whistling pitch.
To make the resonance track the keyboard pitch,
see "4–2a: Keyboard Track" (☞PG p.17).
Selecting a filter to modify the tone
Here's how to select a filter type and adjust the
"Frequency" (cutoff frequency) and "Resonance"
(resonance level).
1. Use "Type" to select a filter type.
Low Pass Resonance: This is a 24 dB/octave
low pass filter with resonance.
Low Pass & High Pass: This is a 12 dB/octave
low pass filter and a 12 dB/octave high pass
filter connected in series.
2. If you've selected Low Pass Resonance as the
filter type, you can set the parameters for Filter
A.
"Frequency" specifies the cutoff frequency.
Overtones above the specified cutoff frequency
will be diminished, making the tone more
mellow (darker).
Using Filters
12dB/oct
Frequency
High resonance
value
53