4.5 Envelopes
There are two envelopes in Saurus that are directly tied to the relevant section they
appear in, the Amp Envelope in the global section, and the filter envelope. But Saurus
offers an additional envelope called Aux (Auxiliary). This can be used for further
modulation of various parameters which can be assigned to the envelope inside
the modulation matrix.
What is an Envelope?
An envelope generator allows a synthesizer to mimic acoustic instruments’ properties of
changing volume and timbre over time. Traditionally, an envelope generator produced a
control voltage that varied over time which could be used to automatically change the filter
cut off or amplifier volume.There are many different types of envelopes but the most common
one is known as an ADSR which is an acronym for Attack, Decay, Sustain and Release which
describes the four controls of the envelope.
Attack – Is a time value which states how long it takes for the envelope to go from zero to
maximum peak when a key is pressed.
Decay – is a time value which states how long it takes for the envelope to drop to the
sustain level.
Sustain – Is a level value which states the highest value while the key is being held down
after the Attack, Hold and Decay stages.
Release – Is a time value which states how long it takes for the the envelope to drop back
down to zero after the key has been released.
4.6 LFOs
There are two LFO's available within Saurus. Both are freely assignable from within the
modulation matrix and can be used basically anything from modulating the filter cutoff to
modulating an oscillator's waveform (LFO>PWM)
LFO WAVEFORM BUTTON – This cycles
the waveform for the LFO to be used. The
available waveforms are :
I) Triangle
II) Square
III) Saw
IV) Ramped random
Note: Additional LFO waveforms (Like a sinoid or smoothed versions) can be created by using
the filter (X) function in the matrix.
FREQ. - This controls at which frequency the LFO runs; the LFO speed
BPM – This will synchronize the LFO's frequency to the host.
PHASE – This will adjust the starting position of the LFO's waveform, when the knob is
turned completely to the left it the LFO will be free running.
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