Vcf - Korg EX-800 Owner's Manual

3.4.5 VCF______________________________________

The Voltage Controlled Filter (VCF) controls tonal quality
(timbre) by selectively removing and emphasizing different
overtones of the DCO waveforms. The VCF used in the EX-800
is a LOW PASS filter: it passes over tones BELOW the Cutoff
Frequency and reduces or removes completely the overtones
ABOVE the Cutoff Frequency. When RESONANCE is turned
up, any overtones very close to the Cutoff Frequency will be
emphasized.
Cutoff Frequency is the most important parameter of the VCF.
Varying the Cutoff Frequency changes the blend of overtones,
resulting in a timbre change (which helps create dynamic and
" lifelike" sounds). Cutoff Frequency is determined by the
CUTOFF ( ! ), RESONANCE ( V.? ), KBD TRACK ( S '3 ),
POLARITY ( ) and EGINT ( VS ) parameters. It can be
also be affected by DEG 3 and/or by the Modulation Gener­
ator (MG).
RESO­
KBD TRACK POLARITY EG INT
CUTOFF
NANCE
I J 1
i j z*
u z*
I ♦ IIL
1 J l
n n i r
C
j .i i j
k
▲
!
▼
▼
n rt
D 0 F F
u LI
PARAMETER NAMES AND FUNCTIONS
CUTOFF
This parameter directly sets the Cutoff Frequency of
the low pass filter.
When the Cutoff Value is set to S3 (assuming both
KBD Track ( '-13 ) and EG INT ( S'S ) are set to 8 ),
all waveform overtones from the DCOs are passed
without any effect, and the sound is very bright.
As Cutoff Value is reduced, more and more harmon­
ics are cut off, producing a more rounded or less bright
sound.
When the Cutoff Frequency Value is near
all of the waveform is filtered out, resulting in almost
no sound.
16
TRIGGER
I J u i j r i j r
1 1
* I
j i
i c
"i
FULL
,? / x 1
"l
▲ MULTI
HALF
▼
SINGLE
\y
/
: (J
t
VCF
0
Bright, unchanged timbre
of DCO waveform
Almost no sound
RESONANCE
Resonance emphasizes the harmonics near the Cutoff
Frequency, producing a characteristic "wah" or " band
pass" type of sound.
u
The higher the Value, the stronger the effect of the
Filter on the tonal quality (timbre). Resonance can
produce typical synthesizer " wah-wah" sounds, helps
make instrumental sounds more realistic, and gener­
ally provides a good variety of subtle and dramatic
effects.
Effect on tone quality
Large (Very peaky sound)
S 3| KBD TRACK
Keyboard Tracking controls how the VCF Cutoff Fre­
quency changes as you play up and down the key­
board. There are three Values: Full, Half and Off.
Full ( .? )
, nearly
TIMBRE
t
Soft timbre
I
VALUE
1
Small
I
None
Cutoff Frequency rises and falls in EXACT
PROPORTION to the pitch of the HIGH­
EST note sounding at any given time
(whether played on the keyboard or pro­
duced by the Chord Memory feature).
This tends to keep timbre (tonal quality)
relatively constant as you play up and
down the keyboard.
VALUE
0
15
0