Korg MS-20 Owner's Manual page 11

5} Features and functions
Voltage Controlled Oscillator WOO]
The VCO is the source of all sound for the M5-20 synthesizer. it is
here that all pitch and basic tonal color elements are determined. The
MS-20 is equipped with two wide-range VCOs.
(I) Scale:
This control is an Octave selector. With each halving of the number
displayed, the pitch goes up one octave. For example the 4' ifootl
scale indication is one octave higher than B': similarly, 16' is one
octave lower than B'. VCO-1 is variable from 32' to 4': VCO-2 is
variable from 16' to 2'.
@ Waveform:
This selects the various waveforms that detemtine the basic tone
color itimbrel. VCO-1 has four vvavafomts:/\,[\,|_|;fi_ "fl": NCO-
2 has three waveforms:|\|_]_ |l_ , plus a Fling Modulator setting.
Each waveform has its own unique characteristic sound.
/\
{Triangle Wavel: A very basic waveform having few harmonies, and
possessing e soft, round tone color. Excellent for flute, vibes and
other such effects. The Triangle Wave may be changed into a Sine
Wave ihaving no hermonicsl by using the Low Pass Filter.
N
lSawtootlii: A waveform rich in all harmonics, and one of the most
useful to the synthesist. Used for string, brass, voice and other
hermonically rich sounds. The Voltage Controlled Filter i'v'CFl is
highly effective on Sawtooth Waveforms.
FL- IL
[Rectangle Wavel: A variable waveform having different timbres
depending on the width of the top [celled Pulse lnlidthl. When the
too and bottom widths are equal, the waveform is called e Square
Wave, and pomesses the "hollow" qualities of the reed family [i.a.,
the clarinetl. As the pulse width prollflrtioneteiy decreases. a
strong shift in tone color occurs: the sound becomes "nasal" in
quality. This waveform is called a Pulse Wave. Pulse Width is varied
on the MS-20 using the PW control {see belowl.
{White Noisal: An unpitched sound consisting of equal amounts of
all frequencies. Used for wind, surf, gunshot, percuwion instrument
and other such effects. The use of filters will emphasize certain
frequencies over others, creating many different sound effects.
FL
i5t|uare Wavel: A variation of the Flectangle Wave with equal top
and bottom widths. A "hollow" sounding wevefonn with only odd
numbered harmonics present. Used to simulate reed instnsments
and other closed pipe sounds.
{Pulse Wave]: This Rectangle Waveform has e relatively narrow top
width, and is characterized by a "nasal" tone quality, with strong
presence of upper harmonics. Used to simulate double reed instru-
ments lea, the oboe] and certain plucked string sounds leg, harpsi-
chord and clevinati.
iFi|NG}Ring Modulator: This setting combines the sounds of both
VCO's in such e way as to create sums and differences of all her-
monics present. The result is a clangorous, "metallic" sound which
is useful for gong, chime and other such effects. The two Scale
controls as well as the Finch and FIN controls all affect the resulting
sound, and should be used iudiciously to create the desired effect.
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@ Pitch:
This control varies VCO-2's pitch over a range of s one octave You
can either match VCO-2's pitch to VCO-1, or set it at any relative
interval leg, third, fifth, etc.i. Once set, pitch levels remain ex-
tremely stable troughout the playing range, thanks to Korg tech-
nology.
@ F"llll:
This control varies the pulse width IFWII of VCO-1's Rectangle
Wave. At "O", the waveform is symmetrical ii.B., Square Wave}.
Fiotating the control clockwise proportionately decreases the pulse
width. Near the full clockwise position, the pulse width becomes
so narrow as to virtually disappear, and no sound will be heard.
BEL-> lib L-cu-
(E) Portamento:
Varies the rate of "glide" . . . the time it takes the MS-20 to go from
note to note. The ability to effect smooth transitions batvveen notes
is unique to the monophonic synthesizer, and adds to the creative
effects available.
@h"lester Tune:
@VCO Mixer:
Independent output level controls for VCO-1 and VCO-2 allow the
user to freely adjust volume balance of the two oscillators, or
eliminate both 'v"CO's when processing external sound sources.
Voltage Controlled High-Pas Filter lVCHFFl
This removes portions of the harmonic elements present in the
waveform chosen with the VCO section. The cut-off frequency is
variable from the low range on up. Use the Cut-Off Frequency knob
or an external control voltage to determine the out-off frequency.
®Cut-off Frequency: The scale on this knob goes from 0 ~ iii
lbut in the "C" position, the filter is completely open and the basic
tone color of the waveform is left unchanged. As you turn up the
Knob, the tone color becomes brighter. Play a note on the keyboard
turn the knob, Hid note the effect.
ifilfleak: This itnob determines the amount of emphasis applied to
the area right before the low range cut-off frequency chosen with
the knob above. When turned up to around its maximum position,
the filter itself begins to oscillate, becoming in effect another sound
source. This self-oscillation capability is another big feature found
in the MS-EC.
Voltage Controlled Low-Pass Filter lVCLFFl
This removes upper herrnonic elements of the waveforms chosen
with the VCO section. The cut-off frequency is variable from the
high range down and is adiosted by means of the Cut-Off Frequency
knob or an external control voltage.
®Cut-Off Frequency: The scale on the knob goes from C ~ 10
but in the "10" position, the filter is completely open and has no
effect on tone color. As you turn the knob counterclockwise the
sound will gredu ally become more rounded. At the lowest setting
it becomes barely recognizable as a sound. Turn the knob while
playing a key and note the effect.
®Feak: This emphasises the point right before the cut-off
frequency. Near its highest position, the filter itself begins to
oscillate. This self-oscillation effect may be used as a separate
sound source.
Cut-off Frequency htodulation Controls:
This control varies the pitch of both VCO"s over e range of 1 2 semi- Th"; °""'i"J'5 Fun" "film" Pam 5* "'9 "i""t""5iZ°" 'F '"'i="'\" "Eh
tones, so that you can match the syntheslzer's pitch with that of
other instruments.
Frequency Modulation controls:
filte|"s out-off frequency, in a manner similar to VCO frequency
modulation.
®lii'lGl'T. EXT:
These controls allow other para of the synthesizer to affect the ycoe The liledvlaliee lfiaearaierh Triansle Wave output modulates the
pitch, for such effects as vibrato, trills, pitch bends, "sweeps", etc.
® lvlerr. ext.
Varies the intensity of 'vibrato from the Modulation Generator iMGl
Triangle Wave output. or whatever signal is patched into the TOTAL
jeclt.
@ee1iex"r=
With no patch in the patch panel's FFIEO jack, this control varies the
effect of Envelope Generator 1 on the 'v'CO's. Advace the control
and play a note on the keyboard. hlote that the pitch of the note
rises and falls corresponding to the Envelope curve isee Envelope
Generator 1i. With any external controller patched in ice. Control
Wheel, Fleverse Envelope, etc.i, the control now varies the intensity
of this effect.
filter frequency, for filter vibrato, automatic "we-we", etc.
risers-zlex'r=
This control varies the modulation intensity from Envelope
Generator 2 iwhen no patch is in the respective filter CUT OFF
FH EO. jacltl. This highly useful effect is called "filter contouring",
and allows you to obtain changes in tonal quality over time. Learri
to use this function, and to experiment with different settings of
Envelope Generator 2 controls.
When an extemai device ie.g., Control Wheel, Pedal, Reverse Envelope
etc.i is patched into the appropriate filter CUT OFF FH E0. lack on
the patch panel, this control varies the intensity of the external
modulation effect.
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