Synthesis page
20
Filter
Type
[Polysix, MS-20 LP, MS-20 HP, 2-pole LP, 2-pole HP, 2-pole
BP, 2-pole BR, 4-pole LP, 4-pole HP, 4-pole BP, 4-pole BR,
Multi Filter]
LP (Low Pass).
This cuts out the parts of the sound which
are higher than the cutoff frequency. Low Pass is the most
common type of filter, and is used to make bright timbres
sound darker.
HP (High Pass).
This cuts out the parts of the sound which
are lower than the cutoff frequency. You can use this to make
timbres sound thinner or more buzzy.
BP (Band Pass).
This cuts out all parts of the sound, both highs
and lows, except for the region around the cutoff frequency.
Since this filter cuts out both high and low frequencies, its
effect can change dramatically depending on the cutoff setting
and the oscillator’s multisample.
With low resonance settings, you can use the Band Pass filter
to create telephone or vintage phonograph sounds. With
higher resonance settings, it can create buzzy or nasal timbres.
BR (Band Reject).
This filter type–also called a notch filter–
cuts only the parts of the sound directly around the cutoff
frequency. Try modulating the cutoff with an LFO to create
phaser-like effects.
2-pole LP, HP, BP, and BR:
These produce 12dB/octave slopes
for LP and HP, and 6dB/octave for BP and BR. A classic
synthesizer expander module used this type of filter.
4-pole LP, HP, BP, and BR:
These produce 24dB/octave slopes
for LP and HP, and 12dB/octave for BP and BR. In comparison to 2-pole filters, these create a sharper roll-off beyond
the cutoff frequency with more delicate resonance. Many classic analog synths used this general type of filter.
Multi Filter.
This is a complex filter which is capable of all of the 2-pole filter types, and many more besides. See “Multi
MS-20 LP and HP:
These 12dB/octave, self-resonating filters lovingly recreate the distinctive timbral signature of the
classic Korg MS-20. Raising Resonance will cause increasing amounts of saturation and overdrive, creating a more
aggressive tone. Input volume can have a strong effect on this character; for more information, see “Gain” on page 22.
Polysix:
This 24dB/octave, self-resonating low-pass filter provides the strong, sweet sound of the classic Korg Polysix.
Cutoff
[-4.00 or +8.00…+136.00 or +138.00 semitones]
This controls the cutoff frequency of the filter, in semitones mapped to MIDI note numbers (60.00 = middle C). The
frequency in Hz is also shown. The specific effect of the cutoff frequency will change depending on the selected Type, as
described above. Most filter types have a range of
-4.00
to
+138.00
, but the
MS-20 LP/HP
and
Polysix
range from
+8.00
to
+136.00
.
Resonance
[0.00…100.00%]
Resonance emphasizes the frequencies around the cutoff frequency, as shown in the diagram below.
When this is set to
0
, there is no emphasis, and frequencies 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.
Low Pass
High Pass
Band Pass
Band Reject
Cutoff Frequency