A plucked envelope would require Decay 2 Level = 0
Decay2 Level = 0 in your MODX amplitude envelope generator describes a
hammered,
struck or
plucked envelope.
Hammered (piano, is an example), struck (vibraphone or a drum, is an example) or plucked (guitar or harp is an example) are the percussive family of musical sounds. The musical vibrations are put in motion by this triggered event. And no matter what you do after having hammered, struck or plucked the instrument, the sound will eventually die out. Even using the “sustain” pedal on a piano does not prevent the vibration from eventually stopping. A sustain pedal (so-called) only delays the inevitable fate of all musical events in the percussive family... they return to silence on their own. It is the hidden forces of gravity and air friction that end the vibration.
The other major family of musical instruments are described as “self-oscillating” instruments... these initiate the musical vibration by bowing or blowing. These have envelopes where
Decay2 Level is
not 0. The note event ends only when the musician stops putting pressure on the instrument. These self-oscillating instruments can maintain the musical vibration, ‘forever’... they can defy the inevitable return to 0
Bowed (a violin, viola, cello are examples), blown (a clarinet, flute, oboe, trumpet are examples - these make up the reed family - lip reeds, single reeds, double reeds, jet reeds.
Bowed instruments can continue sounding by artfully changing the direction of the bow. They are not limited to a single trigger event (as in percussive envelopes) - they can maintain pressure by continuing to move the bow across the string. Blown instruments can continue sounding by artfully
circular breathing. This is where the player uses the lungs exhaling to start musical vibration, they can maintain that outward pressure by collapsing the cheeks while taking air in via the nose (refilling their lungs).
In the self-oscillating instruments the player decides when Decay2 Level reaches 0 (not gravity, not air friction). Whenever they stop applying pressure - which translates to KeyOff on your synthesizer, the AEG immediately advances to the Release Time setting (how the sound will disappear after KeyOff - how it returns to silence).
Try to understand the stages of your synths envelope in terms of these two fundamental families.
Attack describes the start of vibration. Immediate or very near immediate, best describes a percussive attack. It spikes in amplitude at the attack, and often dies to a secondary stage of loudness.
Decay1 Level
Picture a bass drum being struck a mallet... the trigger event spikes as the contact is made... it reaches its loudest almost immediately. The percussive attack is typical heard as a ‘click’ or ‘snap’ at about 1.2kHz through 2kHz. Then the actual size of the bass drum comes into play as the ‘boom’ -- this is described by the envelope moving into the longer low frequency response of the bass drum.. while loud, it is not as loud as that initial attack. That initial attack is called a “transient peak”. This second envelope stage called the Initial Decay can be described in the MODX using Decay1 Level
All hammered, struck and plucked instruments have this “transient peak” located at the front end of their amplitude envelope... and a varying length stay at Decay1 Level. A church bell that rung is loudest at the Attack... it then settles in to its long sustained ring (Decay1 Level) slowly losing energy to gravity and air friction which act to stop it.
Contrast this to the beginning of bowed and blown instruments. While percussion instruments are like vocal “plosives”, bowed and blown instruments can start gradually like words that start with the letters “s”, “f”, etc...
”smooth”,
”freedom”, the sound gradually rises up from silence. Unlike the percussive word beginnings like
“petunia”, or
“boom” which explode with an initial transient attack before the milder sustain portion. The bowed or blown instrument can maintain the exact same volume throughout, they can even adjust that volume during the sustained portion... which can be truly sustained at the same volume if desired... all the way through Note-Off.
If your goal is to create an amplitude envelope that dies out in spite of the key being held... then Decay2 Level must be 0.
And it must arrive their by first traversing the other stages that precede it.
But what about those other settings?
What you need to get a sense of is the TIME parameters... if your TIME parameters are too long, your constructed amplitude envelope may take too long to develop. With TIME parameters the higher the number the longer it takes to traverse this portion of the envelope. Even if you set Decay2 Level = 0 (which we are saying defines “percussive behavior) not all percussive sounds are quick.
Think of a large bell... it is struck once and can ring for more than a minute on a single strike. This is because the TIME settings prior to Decay2 Level are set very high...allowing a long slow AEG.
TIME is how long it takes to travel from one point to the next in the envelope. The higher the number the longer it takes to travel...also how far it travels, or has to travel, also influences your result.
LEVEL in this case, is how loud it is at that time.
Suggestion: Avoid extremes - change settings gradually - they values are NOT linear. Repeat - they are NOT linear! These are constructed specifically to be musically relevant— and are weighted toward where they would be most useful.
Call up the MODX Preset Performance:
“Bass Morpher” — made from sampled (Prophet V sawtooth waves)
In the screenshot below I have selected Part 1
Dropped into [EDIT]
Muted Element 2, 3 and 4 so we can concentrate on just Element 1 (It is important when working on envelopes to isolate the item you are working on - makes it easier to hear your changes.
Navigate to “Elem1” > “Amplitude” > “Amp EG”
As you move the cursor to a Time or Level parameter notice the white pixel in the graphic will indicate where in the AEG you are.
Amplitude Level is the y-axis (up/down) — Time is the x-axis (left-to-right).
I highlighted Decay1 Time = 64
As you slowly increase and/or decrease this parameter value notice the change in behavior of the envelope... re-strike notes to restart the AEG
You can lengthen the Time, the white pixel moves to the right along the x-axis, the sound takes longer and longer to return to 0 but you cannot sustain it forever, because eventually the LEVEL parameters dictate that it will disappear (reach the bottom or floor of the graphic.
A sound will sustain ‘forever’ if Decay2 Level is set to a significant value
and you are holding the KEY or the Sustain Pedal (which takes the place of holding the KEY). ‘Forever’ in quotes because in music that is a fictional quality... we know it as applying pressure to the instrument. If you stop applying pressure to a musical instrument, the sound moves immediately to Release Time... Release Level is not a necessary parameter because it is “musical” silence.