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WARNING - This tutorial describes the old original JSyn API. Please refer to the current docs for more up-to-date information.
JSyn Tutorial
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What is an Envelope?
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Imagine the sound of a bell. It starts very loud and then decays smoothly
to silence. Now imagine the sound of a flute. It start less abruptly, stays
steady as long as the flautist blows, and then dies out fairly quickly
when she stops. This contour, or shape, is an important characteristic
of a sound and is called an "envelope". If the contour describes loudness,
then it is called an "amplitude envelope". But envelopes can also be used
to describe the contours of other parameters such as frequency, or filter
cutoff.
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Here is a plot showing the amplitude contour of a bell. The vertical axis
is amplitude and the horizontal axis is time.
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The envelope can be described as a series of straight line segments. Each
point on the envelope is called a breakpoint.
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Here is plot showing the amplitude contour of a flute.
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The dotted line in the middle section indicates that it could be of any
length depending on how long the note is.
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