Junger Audio d02 - Digital Dynamics Processor - Manual (Page 27)

5. APPLICATION NOTES
APPLICATION NOTES
5
It is possible to choose one of eight different control
characteristics for the dynamics processor. Each of the four
different sets of control characteristics provides ideal dynamics
control for a different type of programme signal as follows:
5.1.
Presets
stereo mode 2-channel-mode
1 - universal 5 - universal
2 - pop music 6 – pop music
3 - speech 7 - speech
4 - live 8 - live
Selecting a particular preset sets up the optimum parameters of the
dynamics processor (attack and release times, threshold levels
and interactions between the multiple signal dependent control
circuits) for a particular kind of programme material.
For example, generally speaking, release times are longest when
using the universal setting and shortest when using the live setting.
(In order to understand the basic Multi-loop principle of the Jünger
Audio dynamics processors please refer to chapter 1.2).
Fixed presets containing optimised parameters for different types of
programme signal are used because, with the great number of
parameters used and the interactions of parameters used in
different stages of the multiloop system, changing of individual
parameters by the user could cause problems.
5.2.
Processing signals
containing
emphasis
If the audio signal was recorded with emphasis, the additional
information of the digital input signals contains a definite emphasis-
control-bit in the AES/EBU or SP/DIF format. This is sometimes the
case in older recordings because it slightly improved the signal-to-
noise ratio of currently used analog-digital converters. Similar to noise
reduction methods in analog magnetic tape recording, the higher
signal frequencies are raised prior to recording, and subsequently
lowered in playback, causing a lowering of the higher frequency noise
level.
If such a signal is compressed or limited in a dynamics processor,
problems will occur as the peak levels for high frequencies do not
represent the true values. The dynamics processor causes a change
in peak levels which would, however, lead to a change in the treble
content after passing through the external deemphasis filter.
Prior to dynamic processing a signal recorded with emphasis must
therefore be linearized, i.e. pass through a digital deemphasis filter.
This filter in the d 02 is automatically switched on if the corresponding
control bit is set in the AES/EBU or S/PDIF format. If the filter is
turned on, the colour of the AES input LED will change to red.
5-1