Junger Audio d07 - Digital Transmission Processor - Manual (Page 41)

B1 – The Junger Audio Dynamics Processor Principle
THE JUNGER AUDIO DYNAMICS
PROCESSOR PRINCIPLES
Changing the dynamic range of an audio signal is inherently a non-linear process.
Unlike an ordinary line amp, the gain of a dynamic range processor is not constant
– it varies with time depending on the specific control algorithm of the dynamics
processor and the changing amplitude of the input signal. These variations in the
gain, which represent the real control process, should take place without any
bothersome side effects to the audio signal itself, effects such as pumping, signal
distortion, sound coloration, or noise modulation. In other words, they should be
inaudible.
The setting of the attack time parameter of a dynamics element effects how the
unit will react to rapid amplitude changes in the audio signal. A long attack time
leads to overshoots (and consequent distortion) because the system is not fast
enough to reduce the gain. A short attack time minimizes the chance of
overshoots, but the more rapid gain changes in such cases have audible side
effects such as "clicks" and other modulation artifacts.
Traditional Compressor and Limiter Designs
Traditional compressor and limiter designs only have one control circuit with one
attack time and one release time. They must be adjusted manually by the user to
optimal settings for processing with as little disturbance as possible through a
process of trial and error. A lot of experience and a lot of time is necessary to get
acceptable results. These settings, once found, are only the right choice for a
certain program signal and must be changed for other program types.
Multi-band designs
These units split the audio frequency spectrum into several frequency bands. The
attack and release times are set independently for each frequency band, giving
independent processing for each band. The problem with this multi-band approach
comes when the outputs of each band’s processor are combined together to
produce the output audio. The spectral balance of this output signal is always
different from the input. The balance of high, mid, and low frequencies is inherently
disrupted, which is particularly objectionable when the signals are music, as in
commercials, concerts, etc.
Multi-Loop designs
The Junger Audio Dynamics Processors work according to a Multi-loop principle .
The various loops each work over the entire frequency spectrum. They work in
parallel, each with a different set of attack and release parameters. Each loop
develops a control signal which is then summed with the controls from the other
loops to produce a single gain control signal applied to one gain control element.
Please see the figure below.
B
1