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

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

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
Dimensions (H x W x D)	88 mm (3.5", 2U) x 483 mm (19") x 310 mm (12.2")
Weight	4,9 kg (10.8 lbs)
Accessorie	RC 55, CMK 5

Product	Article No.	Designation
Pro C 28	501442	Digital FIR Controller, 120 V
Pro C 28	501441	Digital FIR Controller, 230 V