KLEIN + HUMMEL, Pro C 28 - Digital FIR Controller

General Description

Characteristics

Stereo-4-Way digital loudspeaker controller designed for use with studio- and PA-loudspeaker systems
Special digital FIR filtering for a completely independent equalization of system amplitude and phase (FIR = Finite Impulse Response)
"Linear phase" equalization resulting in a constant group delay over the entire frequency range of the system
Additional IIR digital filter section providing user-defined equalization with real-time control of changed parameters:

Parametric EQ with 10 full parametric bands of equalization independently for each channel
Room-EQ with IIR filters

Four separate digital limiters included in every single output channel:

Peak/RMS limiter to avoid distortion and loudspeaker damage by restricting the peak power of the power amplifier
Thermo/excursion limiter to avoid speaker damage caused by overheating of voice coil

Compact 19" 2U rackmount unit
All important set-ups are done automatically by loading the individual parameter setup which is delivered for each studio monitor together with the Pro C 28
All settups in the different menus of the controller can be stored in a system setup
The possibility to optimize the system performance in a given installation by creating individual, room-specific FIR filter setups which can match every desired room equalization

State-of-the-art audio technology and performance

Electronically balanced symmetric analogue input stage with lowest noise figures and distortion
2 stacked AD converters (D/S) on each channel ("Gain Ranging" technique) to provide an input dynamic range of more than 130 dB
Digital signal processing with 48 BIT precision
Latest generation DA converters (D/S)
Smooth LP filtering after DA conversion to guarantee a very musical and clear sound
High performance power supply to provide double voltage regulation for each functional block
Wide connection facilities for analogue and digital signals
Highest quality input transformer can be switched into the analogue input circuit

Extensive limiter concept
Every output channel (4 outputs left channel and 4 outputs right channel) features the following limiter structures which work independently from each other:

Digital peak and RMS limiter in "look-ahead"-technology with digital modelling of the power amplifiers´ load-performance

Short attack time constant for safe prevention of power amplifier clipping
"Controlled Overshoot" allows to use full peak power of the amplifier
RMS limiter restricts the maximum continuous power to the power amp´s max. value

Digital thermo and excursion limiter with modelling of voice-coil temperature and cone excursion

Long attack time constants which is adapted to voice coil heating process of each driver
Prevention of thermal driver damage
Prevention excessive cone excursion

All limiter settings are included in the parameter setup and will be loaded automatically at system setup

Comfortable Operation

Easy stand-alone operation via front panel controls
Alternative operation via remote control RC 55 (optional)
Optional operation via IBM-compatible PC (RS232 port integrated)
Connection of several units via internal MIDI port (IN, OUT, THROUGH)
New parameter setups transfer into the PRO C 28 by connecting a PC to the RS232 port
Internal memory of storing up to 70 different parameter setups
Switching between different parameter setups can be done in real time during normal operation
Every setup (even the selected parameter setup) can be stored within a general system setup
Remote control providing direct access selection of up to four different system setups

Operation with monitor specific parameter setups

To upgrade analogue K + H studio monitors (i.e. K + H models O 300 D)

Room and positioning equalization using the IIR EQ section and creating a room specific FIR filter setup for maximum system performance.
Simple connection between Pro C 28 and K + H monitors via a multicore cable with dedicated multiple pin XLR terminals
System enhancement with one or more additional subwoofers (i.e. K + H model O 900)
Subwoofers will be considered in the parameter setup so that amplitude and phase equalization is extended to the lowest frequencies

One way full range operation

High end digital EQ with multiple delay options and sophisticated limiter concepts in a single unit

Equalization of other studio monitors and sound reinforcement systems
Possibility to use the IIR EQ section and / or the integrated FIR filters to realize filters with a linear phase response

Features

Cutting-edge audio technology

Low distortion electronic or transformer balanced analog inputs
2 stacked Delta-Sigma A/D converters per channel providing more than 130 dB dynamic range
48-bit digital signal processing
High-quality Delta-Sigma D/A converters
Moderate low pass filtering after DA conversion guarantees a “musical” sound stage
Comprehensive power supply with double voltage regulation for each channel
Numerous connection options for analog and digital signals
High-quality input channel can be switched to analog

Comfortable operation

Attractive Blue Vacuum Fluorescent Display (VFD) shows all settings
Simple 3-level shallow menu structure accessible from the front panel
Optional Klein + Hummel RC 55 remote control
PC compatible RS-232 port
Connection of several units for synchronized operation using internal MIDI port (in, out, thru)
Internal memory can store over 70 different parameter setups
Switch between parameter setups during use
All settings can be stored inside the hardware memory
Switching between setups possible using remote control

Delivery Includes


	1x Pro C 28
	1x Power cord
	1x Operation manual

Technical Data

Connections

Analog inputs 2 x XLR, electronically balanced or transformer balanced (switchable)

Impedance 10 kΩ

Max. input level 24 dBu

CMRR > 80 dB @ 15 kHz

Crosstalk > 80 dB

Analog outputs 8 x XLR, balanced

Impedance < 70 Ω

Output rang steps 16, 12, 6 dBu

Resolution, type 24 Bit DA, DS

Digital inputs AES/EBU, XLR (110 Ω transformer balanced, AES3id, S/P-DIF BNC (75 Ω)

Digital outputs (insert) AES/EBU (XLR, transformer balanced)

Remote control, interface MIDI, RS232 (D-Sub D 25)

Baud rate 9600, 31520

Remote control IR remote RC 55 (optional)

Performance

THD 0,0004 % unweighted, 20 Hz - 20 kHz

Noise AD - 126 dBFS

Signal treatment

AD conversion 24 Bit stacked AD, DS

Sample rate 44,1 kHz, 48 kHz

DA conversation 24 Bit, DS

Latency time Basic latency 5-7 ms, channel-dependent)

Filter latency time Depends on filter type

Filter section and limiter

Factory parameter setups

Filter algorithm FIR-filter (Finite Impulse Response)

Max. number of parameter setups Depends on filter length, typ. 50

Filter types Linear phase, mixed linear / minimal phase, minimal phase

Number of output ways 1-4

Equalizations
Individual according to connected speakers, linearized amplitude and phase

Slopes Freely definable up to approx. 96 dB/oct.

Peak limiter Look-ahead type with 1,5 ms and "Controlled Overshoot" to use amplifier´s max. impulse output power

Thermo limiter Simulation of voice coil and magnet temperature

Room-specific parameter setups Same as factory parameter setups, requires individual system alignment by K+H

User-defineable parameter equalizer IIR filter algorithm (Infinite Impulse Response)

Number of filters/channels 10 filters, can be configured as fully parametric, High/Low-Shelving 6/12dB/oct, high/lowpass 6/12 dB/oct; peak filter

Room EQ IIR Filter algorithm (Infinite Impulse Response)

Filtertypes Low-cut; low; mid; high

Delay Master delay 0-999 ms, channel delay 0-92 ms

Power supply

Mains 120 V AC (90-130 V), 230 V AC (160-250 V) internally switchable

Power consumption 32 VA

Mechanical

Height x width x depth
88 (2HE) x 483 (19" EIA Standard rack) x 310 mm,
3.5" (2RU) x 19" (EIA Standard rack) x 12.2"

Weight 4,9 kg (10.8 lbs)

Accessorie RC 55, CMK 5