Junger Audio d02 - Digital Dynamics Processor - Manual (Page 7)

1. THE DESIGN OF THE DEVICE
THE DESIGN OF THE
DEVICE
The d 02 digital dynamics processor can be used to process both
digital and analog audio signals. The device is primarily designed for
use with stereo signals.
Digital input signals can be connected in the AES/EBU standard
format, including SP/DIF and OPTICAL formats.
For the analog inputs high resolution 24 bit A/D converters are used.
The sample rate of the A/D-converter can be syncronised to internal
crystal clock generators or to external word clock signals. Input and
output can be selected independently. The output signals are available
in parallel in all three digital formats so that, depending on the active
input, a format conversion can also be achieved. In addition, an analog
stereo signal output is available which operates with 24-bit D/A
converters and enables a rapid acoustic monitoring.
1.1.
Basic
Functions
1
The increase of signal density and loudness level of the digital audio
signals can be achieved by the interaction of two dynamic range
control processes. Firstly, by the compression achieved by increasing
low and medium signal levels and secondly, by linear amplification
combined with an inaudible limitation of individual remaining peak
levels by the limiter.
The outstanding quality of dynamic range processing is based on the
new Multi-loop dynamic range control principle developed by Jünger
Audio.
The term Multi-loop means that there are several interactively combined
control circuits as opposed to a control circuit with a spectrum split into
several bands with different frequencies (multi-band).
A change in the dynamic range of an audio signal is a non-linear
process. The gain of a dynamic range processor is not constant as it
is with the gain of a linear amplifier. The gain varies in time
depending on the input signal and depending on the specific control
algorithm of the dynamics processor. These variations in the gain,
which represent the real control process, should take place without
any bothersome side effects such as pumping, signal distortion,
sound colouration or noise modulation, which means they should be
inaudible. 1.2.
The
Jünger Audio
Dynamics
Processor
Principle
The main problem here is to react to fast changes in the audio signal
(transients) without the control process being audible and disturbing.
The ability of a dynamic range processor to react to rapid amplitude
changes depends directly on its attack time. Long attack times do not
cause modulation distortions, but lead to overshoots because the
system is not fast enough to reduce the gain. A short attack time
minimizes the amplitude and time of a possible overshoot, but a rapid
gain change has audible side effects such as " clicks" caused by
modulation products.
1-1