Advanced Sound Programming
29
One-Shot LFO as Additional Envelope
If LFOs are otherwise not required (e.g. for pitch or formant modulation), they can be put to good use as additional envelopes. Although
there is no special one-shot LFO mode in the
V-Synth
, this can be simulated using the following trick. Again, this is only an experiment
to show how it works - the sound itself is not particularly useful!
Dive
Start with
512:INIT PATCH
and go to
OSC1
. Touch the
LFO
tab ,
select
SQR
and take
Rate
down to
zero
. Activate both
Key Sync
and the “
ON>>
” Fade button
. Change the
Time
value to
40
. You should now see a short downward sloping
ramp in the LFO graphic display - this is our extra envelope.
5
4
3
2
1
To demonstrate how this could be used to “modify” an envelope, select
OSC1
/
Pitch
,
flip
Sustain
down to
zero
and change
Decay
to
64
. Take
Env Depth
up to +40 so
that the pitch drops at a medium rate
. Play a note and listen to the shape of the decay
- it appears to be linear. Now change
Pit LFO Dp
(Pitch LFO Depth) to
-27
and play a note
. At
-27
, the rising LFO (it was falling, but the modulation depth is negative) cancels out
the first part of the envelope exactly, and you end up with a plateau as long as the LFO
Time
parameter, followed by the rest of the “dive” caused by the envelope.
Of course you can make the one-shot LFO have the opposite effect, e.g. adding it to the
normal filter envelope for an additional short “pluck” at the beginning of each note.
4
3
2
1
1
2
3
4
4
5
1
2
3
4
Pitch Envelope
One Shot LFO
(Pit LFO Dp=-27)
Result of addition
Inverse Envelopes
Not many people ever consider putting envelopes upside-down, although this can be
very useful sometimes. The individual segments change their meanings completely:
A
becomes a decay to minimum after an instantaneous attack
D
becomes a rising slope if the S value is not 127 (minimum!)
S
is inverted i.e. maximum becomes minimum and vise-versa
R
becomes a final rising slope
A D
S
R
Normal Envelope
A D
S
R
Reverse Envelope
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