HK Audio CDR 210 F - Manual (Page 64)

Manual
COHEDRA
® & COHEDRA ® Compact
1 Digital Field
Controller (DFC)
Courtesy of its virtual crossover, the Digital Field
Controller lets you operate COHEDRA
® and all
other biamped sound reinforcement systems of the
HK AUDIO
® Concert Sound Series as you would
active three-way sound reinforcement systems.
This is possible because the DFC splits the input
signal into three frequency bands – the low, middle
and high ranges. It then equalizes, limits, and per-
forms similar functions separately for each frequency
band. After processing the incoming signal, the
DFC blends the middle and high frequency bands
to create a composite signal, thereby delivering the
midrange/high frequency signal required to drive
biamped systems.
This means that even though one power amp channel
drives a mid/high unit via a passive crossover and
using a single speaker cable, you can set levels and
delay times separately for the cabinet's midrange
woofers and high frequency drivers, as well as use
virtual functions to invert phases and mute signals.
The Digital Field Controller designed for use in the
Amp Rack. It implements in digital format all the
functions required to control HK AUDIO
® sound re-
inforcement systems composed of speakers and the
VX 2400 amp. The DFC features FIR filters enabling
comprehensive frequency and phase response cor-
rection. Used in combination with the specially de-
veloped PC control software and Remote Interface,
you have a logical and amazingly convenient control
system readily available. It handles intuitively, en-
abling you to master even the most daunting sound
reinforcement challenges with ease. Its hallmark
features include specially developed filter sets pre-
programmed to EQ varying system and stacking con-
figurations of HK AUDIO
® Concert Sound systems
in combination with VX 2400 power amps.
The DFC features the following functionality:
• PA Remote Management
• System Equalization
• Phase Correction
• Peak / RMS, Temperature and Overshoot Limiter
• EQ
• Delay.
The DFC is equipped with an analog input and a
digital AES/EBU input for patching in signals.
The DFC's analog input is electronically balanced.
Input impedance is 15 k-ohms. Input sensitivity is
0 dBV (equals 1 V RMS); the maximum permissible
input level is 24 dBV. An electronic filter serves to
protect the device against HF interference.
FIR filter technology
FIR filter technology lets you correct the phase and
equalize the frequency response of HK AUDIO
®
sound systems independently. Unlike IIR filters,
FIR filters do not consist of a specific number of
separately computed filter elements. Instead, they
contain a complete sampled copy of the function
required for equalization. The entire filter is re-
computed every time a filter setting is modified.
The DFC features an extendible database archiving
functions for equalization, phase correction, and
power handling capacity specifications of different
HK AUDIO
® speakers and sound reinforcement
systems. You can load new filters programmed for
specific cabinets and speaker configurations into
the DFC's memory using HK AUDIO
® Controller PC
software (see chapter 2.15).
Frequency and phase equalization
The crossover splits the input signal into three
frequency bands. The selected filter equalizes the
entire sound system's frequency and phase response.
This includes all components following the DFC in
the signal chain – amps, passive crossovers, spea-
ker chassis, and speaker housings.
Limiters
The DFC is equipped with temperature and RMS
limiters for all three frequency bands. They feature
forward-looking algorithms that anticipate the
amount of power routed to the amp's outputs. In
the event of impending electrical, mechanical or
thermal overload, they cut the output to allowable
Figure 1: DFC front view