Filter Envelope - Alesis S4 Plus Reference Manual

Chapter 6: Editing Programs
Velocity Modulation (00 to 99)
This determines how keyboard dynamics will affect the envelope level. When set to
99, note velocity controls the envelope's output; notes played hard will deliver a
higher envelope output than notes played soft. When set to 0, note velocity will have
no effect on the envelope's output level.

Filter Envelope

Filter Envelope (Page 1)
Filter Envelope is crucial whenever you want the tonal quality of a note to change
over time, differently from its overall level. Example: When you want the initial attack
of a note to be bright, but want the sustaining part to be filtered.
The following Filter Envelope variables will only have any effect if the FILTER
J
ENVELOPE DEPTH (on Page 2 of the FILTER function) is set to a value other than
0, or, Filter Envelope is a source in the MOD function.
Also note that the Filter Envelope may have no effect if some other modulation
source, or the basic setting of the filter, has already pushed the filter cutoff frequency
to its maximum.
Attack (00 to 99)
This is the amount of time the envelope will take until it reaches its maximum output
level. Setting the Attack to 0 will give a sharp edge to the sound (if the Delay is also
set to 0 in FENV Page 2--see below); a setting of 99 will result in a much slower
attack, taking many seconds before the envelope gets to maximum.
Decay & Sustain (00 to 99)
As soon as the attack portion of the envelope finishes (when the level reaches
maximum), the envelope will decay (decrease in level). The level it reaches is set by
the Sustain control; how long it takes to get there is set by the Decay control. In the
special case where the Sustain level is all the way up (99), then there is no decrease
and the Decay time segment is bypassed. Whatever level the sustain is set to is the
level that the decay section of the envelope will head for. Depending on the setting of
the Sustain Decay control (see below), the envelope will either hold at the sustain
level until you release the note on the keyboard, or decay to 0 at the Sustain Decay
rate (which is on page 2 of the envelope). You can create a long "plateau" at the start
of a note by setting the Sustain to 98 and the Decay to 99. This will cause the
envelope to take the maximum amount of time to get from peak level to a level of 98,
before the Sustain Release portion of the envelope begins.
Release (00 to 99)
Eventually, you will let go of the note that you've been holding (either by releasing the
note on the keyboard, or releasing the sustain pedal if it was pressed). It is at this
point that the Release portion of the envelope takes effect. The Release is the time
that the envelope takes to get from the sustain level back down to nothing. Setting
the Release time to 0 is good for playing those short funky riffs that you hear on a
clavinet. Setting the Release time to 99 will take the envelope a very long time to
reach zero level.
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