Novation Bass Station II - Manual (Page 12)

12
SIMPLIFIED BASS STATION II BLOCk DIAGRAM
Oscillator 1
Ring Mod 1 * 2
Noise
External Input
Oscillator 2
Sub Oscillator
Sub Oscillator
Mixer VCA
Mod Envelope
LFO 2
Filter Overdrive Distortion
Amp Envelope
Oscillator 1
Mod Envelope
LFO 1
LFO 2
pitch
pulse width
Oscillator 2
Mod Envelope
LFO 1
LFO 2
pitch
pulse width
Bass Station II Block diagram
Oscillator modulation controls
1. Audio flow
2. Mod flow
3. Sub Osc control from Osc 1
1. Mod flow
2. Sub Osc control from Osc 1
BASS STATION II IN DETAIL
The Oscillator Section
18 12 13 11 20
15 14 16 17 19
Bass Station II’s Oscillator section consists of two identical primary oscillators, plus a
“sub-octave” oscillator which is always frequency-locked to Oscillator 1. The primary
oscillators, Osc 1 and Osc 2, share a single set of controls; the oscillator being controlled
is selected by the Oscillator switch 11 . After adjustments have been made to one
oscillator, the other may be selected and the same controls used to adjust its contribution
to the overall sound, without altering the settings of the first. You can constantly reassign
the controls between the two oscillators until you get the sound you’re after.
The following descriptions thus apply equally to the two oscillators, depending which is
currently selected:
Waveform
The Waveform switch 13 selects one of four fundamental wave shapes -
Sine,
Triangle, (rising) Sawtooth or Square/Pulse. The LEDs above the switch
confirm the waveform currently selected.
Pitch
The three controls Range 12 , Coarse 14 and Fine 15 set the Oscillator’s fundamental
frequency (or Pitch). The Range switch is calibrated in traditional “organ-stop” units,
where 16’ gives the lowest frequencies and 2’ the highest. Each doubling of stop length
halves the frequency and thus transposes the keyboard pitch down one octave. When
Range is set to 8’, the keyboard will be at concert pitch with Middle C in the centre. (Note
that Oscillator range setting is completely independent of the keyboard’s Octave Shift
function, set with the Octave buttons 3 ).
The Coarse and Fine rotary controls adjust the pitch over a range of ±1 octave and ±1
semitone respectively. The LED display shows the number of semitones above or below
concert pitch as Coarse is adjusted. When Fine is adjusted, the display shows the variation
above or below concert pitch in cents, where 1 cent = 1/100 of a semitone.
Modulation
The frequency of either Oscillator may be varied by modulating it with either (or both) LFO
1 or the Mod Env envelope. The two Pitch controls, LFO 1 depth 17 and Mod Env depth
16 control the depth – or intensity – of the respective modulation sources.
Note that only one LFO – LFO 1 - is used for oscillator modulation. Oscillator pitch can
be varied by up to five octaves, but the LFO 1 depth control is calibrated to give finer
resolution at lower parameter values (less than ±12), as these are generally more useful for
musical purposes.
You will find the following parameter settings generate musically useful
pitch swings:
6 = a semitone 12 = a tone 22 = a perfect fifth
32 = one octave 56 = two octaves 80 = three octaves
Negative values of LFO 1 depth “invert” the modulating LFO waveform; the effect of this
will be more obvious with non-sinusoidal LFO waveforms.
Adding LFO Modulation can add a pleasing vibrato when a sine or triangle LFO waveform
is used, and the LFO speed is set neither too high nor too low. A sawtooth or square LFO
waveform will produce rather more dramatic and unusual effects.
Adding envelope modulation can give some interesting effects, with the oscillator pitch
altering over the duration of the note as it is played. The control is “centre-off”, the LED
display shows a range of -63 to +63 as it is adjusted. With the parameter value set to
maximum, the oscillator pitch will vary over eight octaves. A parameter value of 8 shifts
the pitch of the oscillator by one octave for the maximum level of the modulation envelope