Oscillator Section - Novation KS Rack User Manual

Oscillator Section

Oscillator Section
The Oscillators generate pitched waveforms (as described in the
Synthesis Tutorial chapter) and these are fed into the Mixer. Most of the
controls which determine the pitch and waveform of the Oscillators, and
how they react to modulation are in this area of the front panel.
portamento semitone
detune
-1
1 0
2 +1
+2
3
oscillator solo octave
OSCILLATOR Select Button
There are three independent Oscillators. Each one can be independently
controlled by the buttons and knobs in the Oscillator area. To make make
the controls active and to see waveform and octave settings for Oscillator
1, press the OSCILLATOR button once or more until LED 1 lights. For
Oscillator 2, press until LED 2 lights and for Oscillator 3 press until LED 3
lights.
SOLO Button
While this button's LED is lit, only the currently selected Oscillator can be
heard. The other two Oscillators are muted. This feature is useful for audi-
tioning Oscillators individually while creating complex sounds. press the
SOLO buttun again to resume normal operation.
Note that this button's status is not stored when a Program is saved.
OCTAVE Button
Sets the basic pitch of Oscillator 1, 2 or 3 in Octave jumps. To change the
basic pitch of the selected Oscillator to +1 octave for example, repeatedly
press the OCTAVE button until the +1 LED lights.
NOTE: The 0 position corresponds to the pitch of 440Hz when note A
above middle C is played.
PW SELECT Button and PWM DEPTH / PW POSITION Knob
The function of the PWM DEPTH / PW POSITION knob is dependent on
the selection of the PW SELECT button. With the POSITION setting
selected, the PWM DEPTH / PW POSITION knob will manually control
the pulse width of a square waveform (the selected waveform for the
Oscillator must be Square wave for this to happen). In order to under-
stand how the Pulse Width knob affects various waveforms, examples,
using factory presets are used. See the following paragraphs titled:
Obtaining a classic Square/Pulse PWM sound and Obtaining a
Double Saw 'thick' detuned sound.
With the PW POSITION knob in the central position, the Pulse Width
wave becomes a square wave. As the knob is adjusted clockwise, or anti-
clockwise, the Pulse Width becomes narrower producing what is termed
as a Pulse Wave.
With the LFO 2 position selected by the PW SELECT button, the width of
the Pulse Wave may be modulated by LFO 2. The intensity of this modu-
lation is determined by the PWM DEPTH knob. With the Pulse Width
knob at central position there is no effect. Turning clockwise or anticlock-
wise introduces the effect. Continuous variation in the width of a pulse
waveform (which is what is happening when LFO 2 is modulating it)
changes the harmonic content. This is pleasing to the ear, especially at
lower pitches where all the associated harmonics fall within the audio
range. This creates the classic PWM sound, as described below.
waveform pwm depth/ mod env
pw position depth
position
lfo 2
mod env
more
pw select lfo1 depth
MAIN FEATURES AND OPERATION
When modulated by the MOD ENV, the effect is most apparent when
using fairly long Mod Env Attack and Decay times.
Obtaining a classic Square / PWM sound
The PWM sound is one of the classsic analogue synthesizer sounds.
Select one of the factory initialisation sounds ( 311 - 499) All of these ini-
tial sounds use only use Oscillator 1 as the source waveform. Select a
square waveform using the WAVEFORM button in the Oscillators section.
Notice how the timbre changes to a more 'woody' sound. Select POSI-
TION using the PW SELECT button.
Rotate the PWM DEPTH / PW POSITION knob and notice how the sound
changes to a very thin nasal sound when the knob is towards the clock-
wise or anticlockwise end stop positions. (If fact the sound will extinguish
completely at maximum settings). Leave the knob at the 12 o'clock posi-
tion.
Select LFO 2 using the PW SELECT button. Slowly rotate the PWM
DEPTH / PW POSITION knob. Notice that there will now be some move-
ment in the sound. Select LFO 2 in the LFO's section using the LFO but-
ton. Rotate the SPEED knob in this section and notice how the speed of
the movement will change. Experiment with the above controls until the
desired sound is achieved.
Obtaining a Double Saw 'thick' detuned sound
A thick 'Double Saw' detuned sound using just a single Oscillator may be
created easily. If necessary, this sound can be stacked using additional
Oscillators to product a 'huge' sound. Select one of the factory initialisa-
tion sounds ( 311 - 499). All of these initial sounds use only use Oscillator
1 set to a sawtooth as the source waveform. Select POSITION using the
PW SELECT button.
Rotate the PWM DEPTH / PW POSITION knob fully clockwise. As the
control is rotated, a double sawtooth wave is generated. At this fully clock-
wise position the pitch will appear to double.
Select LFO 2 using the PW SELECT button. Slowly rotate the PWM
DEPTH / PW POSITION knob. Notice that there will be some movement
in the sound. Select a sawtooth LFO wave using the WAVEFORM button
in the LFOs section. Press the LFO button to select LFO 2. Rotate the
SPEED knob in this section and notice how the speed of the movement
will change. Experiment with the above controls until the desired sound is
achieved.
PORTAMENTO Knob
This knob adjusts the Portamento effect. With this control set to zero,
when the keyboard is played, the pitches of notes change instantly from
one pitch to another as different keyboard notes are played. Turning the
knob clockwise introduces the Portamento effect. Notes will glide smooth-
ly from one pitch to the next. Increasing the amount will slow the time
taken for the pitch of the first note to reach that of the second note played.
WAVEFORM Knob
This knob sets the currently selected Oscillator's waveform. As the knob
is turned, the WAVEFORM LEDs indicate which waveform is currently
selected. There are 32 waveforms available. The first 4 of these are the
traditional waveform shapes found on classic analogue synthesizers. The
next 4 are special noise types. The remaining 24 are digitally sampled
waveforms that provide useful sources fro emulating more tradional instru-
ments and percussion sounds..
When this knob is at the fully anti-clockwise position, the Sine waveform
is selected. As the knob is turned clockwise, the other traditional wave-
forms are selected. After these, the more complex harmonic waveforms
are available. Whenever one of these is selected, the MORE LED will be
lit on the front panel.
On the following page is a table of all the Oscillator waveforms available.
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