Alesis A6 User Manual
Chapter 7: LFOs, S&H and Process
A
NDROMEDA
A6 R
EFERENCE
M
ANUAL
175
TRIG Page
As important as how an LFO operates is when it begins to oscillate. It is usually
assumed that an LFO starts when a key is played or MIDI Note is received, or at
the end of the Delay stage. All three of these scenarios are correct, but more
accurately, it is the trigger that originates from the keyboard or MIDI that starts
the end of the Delay stage. All three of these scenarios are correct, but more
accurately, it is the trigger that originates from the keyboard or MIDI that starts
the LFOs’ oscillation. This page allows you to do more than that.
The
TRIG
page in the LFO section is mostly about allowing you to start the
LFO's oscillation from something other than a key hit. None of the variables on
this page will take effect until the
this page will take effect until the
VOXTRG
parameter is set to
ON TRIG
. Its
default setting is
ON VOX
which initiates the LFO when a voice is activated from
the keyboard or MIDI, as is customary.
SOURCE
Trigger Source
This menu is probably familiar to you by now—it contains the 79 Mod Sources
covered in Appendix B.
Depending on the source, you may set an LFO to start only above or below certain
key ranges, or when a particular envelope stage is set, or in response to a MIDI
message. The possibilities are huge.
key ranges, or when a particular envelope stage is set, or in response to a MIDI
message. The possibilities are huge.
LEVEL
Trigger Input Level
This sets the threshold level for the trigger, up or down. A setting of zero is in the
middle. For many trigger sources, the level must be positive to achieve a trigger.
But for others, you may need to reduce it so that the LFO is triggered only when
you want it to be.
But for others, you may need to reduce it so that the LFO is triggered only when
you want it to be.
Range: ±100.00 in increments of .01.
TYPE
Trigger Type
This sets the conditions or rules under which a trigger will occur as the input
source crosses the threshold level. See page 143, the
source crosses the threshold level. See page 143, the
POLAR
parameter, for
explanations of the values for Trigger Type. The illustrations on pages 155-157 in
the Modulation section will also help you understand the meaning of
NEGATIVE,
POSITIVE, BIPOLAR, ABS NEGATIVE, ABS BIPOLAR,
and
ABS
POSITIVE
.
ENABLE
Trigger Enable (ON or OFF)
Soft Knob #6 of this page turns the whole Trigger source for the LFO on or off.
When it is ON, the
When it is ON, the
TRIG
LED on the top panel (next to the LFO's
VIEW
button) will
light.
Even if TRIG ENABLE is ON, the LFO will not be triggered from the selected trigger
SOURCE unless
VOXTRG
is set to
ON TRG
. The TRIG LED doesn't have to be on
for the LFO to be triggered by the standard voice/key on trigger path.
VOXTRG
LFO Trigger from Voice (
ON VOX
or
ON TRG
)
Soft Knob #7 of this page determines whether the LFO will start from its default
source (
source (
ON VOX
, meaning when a key or MIDI input triggers the voice) or from
the trigger source chosen by Soft Knob #1 on this page.
FREERN
LFO Freerun (ON or OFF)
Soft Knob #8 of this page determines whether the LFO will always start at the
beginning of its cycle when it receives a trigger (Freerun OFF), or simply keep
oscillating and not restart when it receives a trigger.
oscillating and not restart when it receives a trigger.