Vcf; Vca; Adsr; Lfo - MFB SYNTH LITE II Operator's Manual

VCF

----------------------------------
Each oscillator's output is set with its LEVEL control. These signals plus any signal
connected to the AUDIO IN are mixed and routed into the voltage controlled low pass
filter. CUTOFF sets the filter working point. Any frequency higher than the cutoff
frequency will be attenuated. And since the VCF operates with 24 dB/oct the
attenuation is quite steep and effective. EMPHASIS enhances the CUTOFF frequency area
by boosting it. When turning up EMPHASIS fully clockwise the filter even starts to self-
oscillate with a sinoid wave. It might be useful to couple the cutoff frequency to
incoming keyboard notes. This can be done in the System Settings by setting Keyboard
Follow to ON.
External signals connected to AUDIO IN are routed directly to the VCF.
CONTOUR adjusts the cutoff modulation by envelope ADSR.

VCA

----------------------------------
The final stage in signal processing is the voltage controlled amplifier. Its shape is
controlled by envelope ADSR 2.

ADSR

----------------------------------
The SYNTH LITE II has two envelope generators: ADSR1 (VCF) and ADSR2 (VCA). They
each offer four parameters. ATTACK (time from zero level to maximum level when
triggering a note), DECAY (time from maximum level to sustain level), SUSTAIN (level
while holding a note) and RELEASE (time from sustain level to zero level after releasing
a note). RELEASE has no individual control. It is either fixed in duration or equivalent to
DECAY (set in System settings).

LFO

----------------------------------
The LFO (low frequency oscillator) offers selectable triangle, saw tooth and square
waveforms. RATE sets the oscillation speed between approximately 10 sec and 100 Hz. If
all three LEDs are lit the LFO is set to saw tooth one-shot mode. Here, the modulation is
not cyclic but runs through the waveform only once when triggered.
DEPTH sets the modulation target and intensity. Turn counter clockwise from centre to
modulate the oscillator section in pitch (or pulse width) with increasing intensity. Turn
clockwise from the centre position to modulate the filter's cutoff frequency. Leave the
control in centre position disables LFO modulations.

Oscillator sync

----------------------------------
Oscillator sync is activated if all OSC 2's LEDs are lit. Every new wave cycle of OSC 1
forces OSC 2 to restart its cycle, too. OSC 2 is therefore controlled or synchronized to
OSC 1 frequency. With Sync activated, modulation will only target OSC 2, resulting in
intense timbres instead of pitch modulations.