CHAPTER 21. LIVE AUDIO EFFECT REFERENCE
315
21.19.1
Dynamics Processing Theory
To understand how to use the Multiband Dynamics device, it helps to understand the four
different methods of manipulating dynamics.
When we use the term compression, we're typically talking about lowering the level of
signals that exceed a threshold. This is how Live's
Compressor
works, and is more accurately
called
downward compression
because it pushes loud signals down, thus reducing the
dynamic range. But it is also possible to reduce a signal's dynamic range by
raising
the
levels of signals that are
below
a threshold. This much-less-common form of compression
is called
upward compression.
As you can see from this diagram, employing either type of
compression results in a signal with a smaller dynamic range than the original.
original
dynamic
range
smaller
dynamic
range
downward compression
(common)
original
dynamic
range
smaller
dynamic
range
upward compression
(uncommon)
Downward and Upward
Compression.
The opposite of compression is expansion. A typical expander lowers the levels of signals
that are below a threshold. This is how Live's
Gate
works, and is more accurately called
downward expansion
because it pushes quiet signals down, thus increasing the dynamic
range. It is also possible to increase a signal's dynamic range by
raising
the levels of signals
that are
above
a threshold. Like upward compression, this technique is known as
upward
expansion
and is much less common. This diagram shows that either type of expansion
results in a signal with a larger dynamic range.