E-Mu Ultraproteus Operation Manual page 109

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 two different envelope generators on
UltraProteus. The Alternate Volume Envelope generator controls the volume of
the primary or secondary instrument over time and has 5 stages: Attack, Hold,
Decay, Sustain, and Release. There is also an Auxiliary Envelope generator
which is a general purpose envelope and can be routed to any realtime control
destination. The Auxiliary Envelope has an additional delay stage before the
attack. 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 vol-
ume, then slowly dies away. A bowed violin sound fades in more slowly and dies
away slowly. Using the Alternate Volume Envelope, you can simulate different
types of instrument volume envelopes by programming them appropriately. By
routing the Auxiliary Envelope to control the pitch (realtime control screen)
you can easily hear the shape of the envelopes you are creating.
The envelope generator parameters can be described as follows. Refer to the
diagrams on the following page.
Delay
The time between when a key is played and when the attack phase begins.
Attack
The rate at which the envelope will go from zero to the peak (full) level.
Hold
The time the envelope will stay at the peak level before starting the decay
phase.
Decay
The rate at which the envelope will go from the peak level to the sustain
level.
Sustain
The level at which the envelope remains as long as a key is held down.
Release
The rate at which the envelope will fall to the zero level after the key is
released.
PRESET PROGRAMMING
Chapter 7: Preset Programming
SHORTENING THE RELEASE
TIMES OF THE ALTERNATE
ENVELOPE CAN ALLEVIATE
CHANNEL "RIPOFF" PROBLEMS.
ULTRAPROTEUS EXAMINES THE
ALTERNATE ENVELOPE TO
DETERMINE IF A CHANNEL CAN
BE REUSED.
Piano
Organ
Strings
Percussion
THE GENERALIZED ENVELOPE
SHAPES OF A FEW TYPES OF
SOUNDS ARE SHOWN ABOVE.
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