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.
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
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
in the original multi-
This area of overtones
will be diminished
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.
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
When this is set to 0, there is no emphasis, and fre-
quencies beyond the cutoff will simply diminish
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"
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
"Frequency" speciﬁes the cutoff frequency.
Overtones above the speciﬁed cutoff frequency
will be diminished, making the tone more