About Signal Processing - Alesis QS6.1 Reference Manual

Part 8: Editing Programs
LFO (L
OW
The pitch, filter, and amp modules each have a dedicated LFO module for
modulation. The term LFO stands for low frequency oscillator, and comes from how
modulation was created in the early synth days (an oscillator set to a low frequency
could modulate some aspect of the sound; routing the LFO to the pitch, for example,
would create vibrato). The LFO creates a cyclic (periodic) modulation; this amount
can be constant and/or varied with a variety of modulation sources (mod wheel is
one of the most popular). Each LFO has a waveform shape and speed, along with
other controls.
E
NVELOPES
Envelope generators provide a modulation signal that varies over time, from the time
you strike the key until after you let go. There are three independent envelope
generators (for pitch, filter, and amp) in each Program Sound. An envelope generator
has different effects on different modules. Example: The Amp Envelope creates level
changes. Amplitude that decays over time creates percussive effects (plucked strings,
drums, etc.). Amplitude that increases over time gives the effect of brass, woodwind,
and some bowed instruments.
Each envelope generator has the standard attack, decay, sustain, and release
parameters found on most synthesizers, along with delay, sustain decay, and
different triggering options.
A S
BOUT IGNAL
The QS6.1 features a signal processing section based on the Alesis QuadraVerb 2. It is
a complete digital signal processing unit with four input buses, simultaneous
multiple effects, and flexible signal routing.
Sound 1
Effects parameters are edited separately from either the Program or the Mix, using
Effects Edit Mode (but must be stored within a Program. More in Part 6: Editing
Effects). In Program Edit Mode, each of the four Sounds in the Program has its own
Effect Level control and can be assigned to any one of the four effect buses. Effects
settings, Effect Level and Bus information are saved with the Program when you
store it back into memory.
110
F O
REQUENCY SCILLATOR
L
E
V DELAY ATTACK
E
L
TIME
NOTE ON
P
ROCESSING
)
DECAY
SUSTAIN LEVEL
RELEASE
SUSTAIN DECAY
NOTE OFF
Effects
Processor
(reverb, delay,
chorus, etc.)
QS6.1 Reference Manual
Main L
Main R