• 8000 Watt power, 4 x onboard amplifiers
  • 143 dB max SPL
  • RDNet networked management and monitoring
  • 48 kHz, 32 bit DSP processing
  • 2 x 12” neodymium woofers
  • 4 x 6" neodymium woofer midrange
  • 2 x 3” titanium dome neodymium compression drivers
  • Remarkably compact and lightweight

The HDL 50-A 4K is an active 3-way line array module for large-sized events, indoors and outdoors. It features a sound pressure level of 143 dB SPL with a built-in 8000 W PEAK, 4000W RMS Class-D four-channel amplifier. Equipped with eight best-of-class transducers, it offers excellent playback quality ideal for professional musical applications. The proprietary 90 x 10 degrees 4PATH waveguide with the symmetrical design of the cabinet delivers optimal coverage.


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The most powerful HDL array ever made by RCF

The 4K amplifier doubles the power of the HDL 50-A to achieve new levels of clarity and absence of distortion. Transducers work at full performance and the SPL output is more than doubled. Furthermore, we improved the power supply section with a tripled current level on fast transients, for a level of detail usually achieved only in high-end studio monitors.

Faster and more powerful

The 4K amplifier is an essential part of HDL 50-A reengineering effort. The 4000 W RMS Class-D power operates at very low impedance producing a quick and detailed transient response, while the high damping factor improves sound quality and detail.
The HDL 50-A 4K power section is tailored to the transducers and the cabinet design to reach excellent efficiency, low distortion and high signal-to-noise ratio. The amplifier module features a solid machined aluminum structure that stabilizes the amplifier during transportation.
The control panel on the back adjusts volume, bypass, delay, presets and advanced functions. The signal input preamplifier features a double opto isolation to avoid noise and ground loops.
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DSP Processing

New generation DSP handles processing inside the cabinet and allows for the adjustment of Cluster size and HF projection. The low-latency 32 bits DSP section deploys a remarkable amount of processing power for live performances with straight-forward control and monitoring of individual sections of the module, including the onboard inclinometer and transducer performance via RDNet. An entire set of protections preserve product life and reliability. All settings are controllable by the encoder on the rear of the cabinets or using the integrated RDNet remote management. The easy-to-access control panel allows for simple optimizations of the module.
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Networked control and much more
RDNet is a robust management network and control platform for small, medium and large arena-sized sound systems, as well as complex and extended installations. Based on a proprietary network protocol, RDNet provides intuitive control and monitoring of every connected device/object in the RCF audio system. Each device has DSP to address specific presets or modifications of parameters to single or groups of objects. A network user can change level, delay, EQ (linear phase FiR as well) and other settings, including advanced subwoofer configurations. RDNet is not only designed for loudspeakers—you can control parameters and routing of multiple RCF devices, such as digital matrixes or amplifiers.
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V-shaped symmetrical design

The symmetrical design of the cabinet produces identical left / right coverage. The component arrangement and the special DSP crossover filtering of the HDL 50-A allow for a constant directivity without spots of break up or attenuation. The V-SHAPED front baffle provides:
  • Coplanar midranges and woofers
  • Controlled LF dispersion
  • Central space to host the HF guide
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The custom 4PATH designed waveguide allows a precise coverage of 90 x 10 degrees, while also delivering a superb, linear high frequency response. The unique shape of the four ducts forming the guide create an ideal isophasic load from 800 Hz to the highest audible frequencies.

Neodymium RCF precision transducers

High frequencies - Two ND 840 large format compression drivers are one of the key advantages of the HDL 50-A. The 3.0” voice coil allows for a crossover point of 800 Hz. The driver itself delivers a sizable portion of vocal range with better intelligibility.
Mid frequencies - 4 x 2.0” voice coil 6.0” neo midranges - Water resistant fiber doped cone - Polycotton M-roll surround - High power magnetic structure.
Low frequencies - 2 X 3.0” voice coil neodymium 12” woofers - Water resistant fiber doped cone - Polycotton M-roll surround - Hypervented magnetic structure.
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The RCF engineers constructed an innovative housing consisting of rigid plywood and polypropylene side panels with integrated handles to lower the total weight.

Fly-ware & hardware

The integrated rigging hardware is both fast and reconfigurable, allowing the system engineer to create J-shaped and spiral arrays starting with 0.5° splay angles. The angling of the system develops on a single backbone. Up to 20 HDL 50-A 4K modules can be fastened on a single flybar. The hardware design let angle adjustments before use / on the ground and slip automatically into the correct position when pulling up the array. The system administrator has then only to fix it with a lock pin. Easy and fast set up. The heavy-duty front grille is powder-coated. A special transparent-to-sound foam backing inside helps to further protect the transducers from dust.

New perspective on linearity

RCF speakers are designed using a proprietary and advanced digital FiR technology, conceived to deliver transparent sound, absolute clarity, and perfect imaging to the listener. The special FiRPHASE filters allow for coherent distribution of sound for all listeners without phase distortions, ensuring minimum latencies in the system.
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Acoustical specifications
Frequency Response:
40 Hz ÷ 20000 Hz
Max SPL @ 1m:
143 dB
Horizontal coverage angle:
Vertical coverage angle:
Compression Driver:
2 x 1.4'' neo, 3.0'' v.c
4 x 6.0'' neo, 2.0'' v.c
2 x 12'' neo, 3.0'' v.c
Input/Output section
Input signal:
Input connectors:
XLR, RDNet Ethercon
Output connectors:
XLR, RDNet Ethercon
Input sensitivity:
+4 dBu
Processor section
Crossover Frequencies:
200 Hz - 800 Hz
Thermal, RMS
Soft Limiter
Cluster size, HF correction, RDNET
Power section
Total Power:
8000 W Peak
High frequencies:
2000 W Peak
Mid frequencies:
2000 W Peak
Low frequencies:
4000 W Peak
Powercon IN/OUT
Standard compliance
Safety agency:
CE compliant
Physical specifications
Cabinet/Case Material:
Baltic birch plywood
Integrated Mechanics
2 side, 2 rear
366 mm / 14.41 inches
1171 mm / 46.1 inches
502 mm / 19.76 inches
58.4 kg / 128.75 lbs
Shipping information
Package Height:
400 mm / 15.75 inches
Package Width:
1200 mm / 47.24 inches
Package Depth:
600 mm / 23.62 inches
Package Weight:
62.4 kg / 137.57 lbs