15
Main Features and Operation
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 that determine the pitch and waveform of the
Oscillators, and how they react to modulation are in this area.
OSCILLATOR Select Button
There are three independent Oscillators and each one can be inde-
pendently controlled by the buttons and knobs in the Oscillator area. To
make make the controls active and see waveform and octave 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.
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.
WAVEFORM Button
This control sets the currently selected Oscillator’s waveform.
Repeatedly press until the desired waveform shape LED light.
PW (Pulse Width) SOURCE button and PWM (Pulse Width
Modulation) 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
anticlockwise, 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
modulation is determined by the PWM DEPTH knob. With the Pulse
Width knob at central position there is no effect. Turning clockwise or
anticlockwise introduces the effect. Continuous variation in the width of
a pulse waveform (which is what is happening when LFO 2 is modulat-
ing it) changes the harmonic content. This is pleasing to the ear, espe-
cially at lower pitches where all the associated harmonics fall within the
audio range. This creates the classic PWM sound, as described below.
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/Pulse 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
initial 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 POSITION 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 clockwise or anticlockwise end stop positions. (If fact the sound will
extinguish completely at maximum settings). Leave the knob at the 12
o’clock position.
Select LFO 2 using the PW SELECT button. Slowly rotate the PWM
DEPTH / PW POSITION knob. Notice that there will now be some
movement in the sound. Select LFO 2 in the LFO’s section using the
LFO button. Rotate the SPEED knob in this section and notice how the
speed of the movement will change. Experiment with the above con-
trols 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 addi-
tional Oscillators to product a ‘huge’ sound. Select one of the factory
initialisation 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
clockwise 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 move-
ment in the sound. Select a sawtooth LFO wave using the WAVE-
FORM 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 smoothly 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.
SEMITONE knob
Raises or lowers the selected Oscillators pitch in semitone increments
up to a full octave. By setting the pitch of Oscillator 1 to zero and
adjusting the pitch of Oscillator 2 and 3 by differing amounts results in
some musically pleasing intervals. Settings 5 (a perfect 4th), 7 (a per-
fect 5th), 3 (minor 3rd), 4 (major 3rd), 8 (minor 6th) and 9 (major 6th)
offer the best results.
DETUNE Knob
Sets the detune amount in Cents for the selected Oscillator 1,2 or 3. If
it is set fully clockwise, Oscillators pitch will be 50 cents sharper than
its basic pitch, fully anticlockwise and it will be 50 cents flat.
Slight detuning between each Oscillator will enrich the sound by intro-
ducing a beating between the Oscillators (in the same way a 12-string
guitar sounds richer than a 6-string). Bass and lead sounds can be fat-
tened up using a small amount of detune. Large amounts of detuning
will lead to more extreme effects.
MOD ENV DEPTH Knob
Controls the amount of pitch modulation to the currently selected
Oscillator from the Mod Envelope. In the centre position there is no
effect on the oscillator's pitch, anticlockwise the effect is negative (i.e.
the pitch drops and then rises) and clockwise positive (the pitch rises
and then falls).
See Envelopes Section, on Page 18 for the setting of the rise and fall
times.
To Next Page
Loading...