Types Of Dynamics Processing - PRESONUS STUDIOLIVE 16.4.2 - V1.12 User Manual

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5.3 A Brief Tutorial on Dynamics Processing

Types of Dynamics Processing

5.3.2
Dynamics processing is the process of altering the dynamic range of a signal, thereby enhancing
the ability of a live sound system or recording device to handle the signal without distortion or noise
and aiding in placing the signal in the overall mix.
Compression/Limiting
Punch, apparent loudness, presence—these are just three of the many terms used to describe the
effects of compression/limiting.
Compression and limiting are forms of dynamic-range (gain) control. Audio signals have very wide
peak-to-average signal-level ratios (sometimes referred to as dynamic range, which is the difference
between the loudest level and the softest level). The peak signal can cause overload in the audio-
recording or sound-reinforcement chain, resulting in signal distortion.
A compressor/limiter is a type of amplifier in which gain is dependent on the signal level passing
through it. You can set the maximum level a compressor/limiter allows to pass through, thereby
causing automatic gain reduction above some predetermined signal level, or threshold. Compression
refers, basically, to the ability to reduce, by a fixed ratio, the amount by which a signal's output level
can increase relative to the input level. It is useful for lowering the dynamic range of an instrument
or vocal, making it easier to record without distorting the recorder. It also assists in the mixing
process by reducing the amount of level changes needed for a particular instrument.
Take, for example, a vocalist who moves around in front of the microphone while performing,
making the output level vary up and down unnaturally. A compressor can be applied to the signal
to help correct this recording problem by reducing the louder passages enough to be compatible
with the overall performance.
How severely the compressor reduces the signal is determined by the compression ratio and
compression threshold. A ratio of 2:1 or less is considered mild compression , reducing the output
by a factor of two for signals that exceed the compression threshold. Ratios above 10:1 are
considered hard limiting.
As the compression threshold is lowered, more of the input signal is compressed (assuming a nominal
input-signal level). Care must be taken not to overcompress a signal, as too much compression
destroys the acoustic dynamic response of a performance. (That said, overcompression is used by
some engineers as an effect, and with killer results!)
Limiting refers to the processing that prevents the signal from getting any louder (that is, it prevents
any increase in the signal's amplitude) at the output.
Compressor/limiters are commonly used for many audio applications. For example:
• A kick drum can get lost in a wall of electric guitars. No matter how much the level is increased,
the kick drum stays lost in the "mud." A touch of compression can tighten up that kick-drum
sound, allowing it to punch through without having to crank the level way up.
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