7
The Amplifier Envelope
Long-term exposure to this sound will definitely grate on your nerves, so let’s get started with changing it
into a signal you might enjoy hearing, beginning with the volume characteristics. Locate the section
labeled
AMPLIFIER
at the bottom right of the control feature panel of the Virus. Here you can see five
pots labeled ATTACK, DECAY, SUSTAIN, TIME and RELEASE, respectively. These controls will help you to
dial in volume characteristics called an amplifier envelope and put an end to the nerve-racking drone
that may remind you of one of those cheesy organs that you hear in ‘60s B-movie sound tracks.
Rotate the
ATTACK
pot while you repeatedly engage a key to hear the note. The further you turn the pot
up, the longer it takes for the sound to achieve maximum volume after the start of the note. So you can
say ATTACK controls the initial volume swell of the sound.
Presumably the ATTACK pot was set to a random position before you made any adjustments.
Nevertheless the volume automatically increased to the maximum level before you started rotating the
pot. The reason for this is that an ATTACK value of 0 is saved in the sound program - START - and this
value remains valid until you determine a new value by adjusting the position of the pot, even if you turn
it ever so slightly.
Take a look at the display of the Virus to gain an impression of the difference between these two values.
It shows two numeric values when you dial a pot: at the left you can see the value stored in the sound
program and at the right, the numeric equivalent to the value determined by the current position of the
pot.
NOTE:
NOTE:
Always keep in mind that for a programmable synthesizer the position of the control feature or
pot does not necessarily indicate the actual value of the given function. The reason for this is
that when you first activate a sound program, it will reflect the programmed value. You have to
adjust the control feature before the programmed value is superseded by the value you
determine manually.
Now fiddle with the
DECAY
pot while you repeatedly press a key to activate a note. Hold the key down
for good while. You will notice that the volume, once it reaches maximum level at the end of the
ATTACK phase, drops until it reaches a minimum level. The DECAY pot determines the speed, or in
synthesizer jargon, the rate at which the volume decreases. However, the DECAY level does not always
drop to the minimum level; you can determine a random value between the maximum and minimum
levels at which the volume remains constant. This level in turn is controlled via the SUSTAIN pot.
Whenever the SUSTAIN level is set to maximum, the volume cannot drop during the DECAY phase; in
other words, in this situation the DECAY pot is ineffective.
NOTE:
NOTE:
The individual functions of a synthesizer are designed to interact; many functions are
dependent on other functions. In a number of cases this means that some functions are
subordinate to others, i.e. the effectiveness of a control feature is altered, modified or even
negated completely by other related functions.
The next phase of the amplifier envelope is determined by the
SUSTAIN-TIME
pot: If the pot is set to
the center position (12 o’clock) indicated by the mathematical infinity symbol, then the SUSTAIN level
remains constant through to the end of the note; if you turn it counter-clockwise to the left (towards
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