E-Mu PROTEUS FX Instrukcja Użytkownika Pobierz pdf (Strona 106)

7 - Synthesizer Basics

Envelope Generators

106 Proteus VX Operation Manual

Envelope Generators

An envelope can be described as a “contour” which can be used to shape the sound in

some way over time. There are three envelope generators per voice and all of them are

the rate/level type.

 The EOS envelope

generators are just like

standard ADSR’s, except

that they have two

segments for each stage.

To create a standard

ADSR curve, set the “2”

levels the same as the “1”

levels and set all the “2”

rates to 0.

This is how the rate/level envelopes work: When a key is pressed, envelope starts from

zero and moves toward the Attack 1 Level at the Attack 1 Rate. As soon as it reaches this

first stage, it immediately begins the Attack 2 phase and moves toward the Attack 2

level at the Attack 2 rate. As long as the key is still held, the envelope continues on

through the Decay 1 and Decay 2 stages. If the key is still held when the envelope

reaches the end of Decay 2, it simply stops there waiting for you to release the key.

When you release the key, the envelope continues through its Release 1 and Release 2

stages, stopping at the end of the Release 2 stage. The rate/level envelopes give

maximum flexibility to program both complex and simple envelopes.

The Amplifier Envelope generator controls the volume of the voice over time and has 6

stages: Attack 1, Attack 2, Decay 1, Decay 2, Release 1 and Release 2. The Filter

Envelope generator controls the filter morph and also has 6 stages. Unlike the amplifier

envelope, however, the filter envelope has the ability to go negative as well as positive.

There is also an Auxiliary Envelope generator which is a general purpose envelope. The

auxiliary envelope is identical to the filter envelope and can go negative as well as

positive. The time of each stage can be adjusted to create myriad envelope shapes,

which in turn shape the sound over time.

The way the volume of a sound changes over time determines how we perceive that

sound. For example, a bell struck with a hammer is instantly at full volume, then slowly

dies away. A bowed violin sound fades in more slowly and dies away slowly. Using the

Amplifier Envelope, you can simulate different types of instrument volume envelopes

by programming them appropriately.

Retriggering

The Filter and Auxiliary envelopes can be retriggered by an LFO or any other

modulation source such as clock divisor. (See “

Clock Modulation” on page 108.)

Patch the desired modulation source (using a positive value) to Filter Env Trigger or

Aux Env Trigger. Envelopes are triggered on a positive-going edge.

Complete Mode

In Complete mode, the envelope generator continues through all six stages when a key

is pressed, ignoring the status of key sustain. This feature allows you to create long

evolving soundscapes with a quick tap of the key, enveloping percussive sounds such

as piano and drums, or plucked strings. This mode is also useful to conserve CPU

resources, since the voice will turn off as soon as the amp envelope cycle completes.

Atk1

Atk2

Dcy1

Dcy2

Rls1

Rls2

Key

Down

Key

Released

Sustain

time

level

Holds here

until key release

1 2 ... 101 102 103 104 105 106 107 108 109 110 111 ... 133 134

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