The demands of modern sound reinforcement systems are higher than ever before. Besides pure performance - high sound pressure levels, constant directivity and sound quality other aspects are important for rental and production companies such as reduced weight and ease of use to optimize transport and rigging time.

HDL 50-A is changing the concept of large format arrays, providing primary performances to an extended market of professional users.



The HDL 50-A is a fully active 3-way speaker system that is equipped with both modern and innovative technology.

Each component from the power supply to the input board with DSP to the output stages to woofers and drivers has been consistently and specially developed by RCF’s experienced engineering teams for the realization of the HDL 50-A system, with all components carefully matched to each other.

This complete integration of all components allows not only superior performance and maximum operational reliability, but also provides users easy handling and plug & play comfort.

Besides this important fact, active speakers offer valuable advantages: while passive speakers often need long cable runs, the energy loss due to the cable resistance is a huge factor. This effect is not seen in powered speakers where the amplifier is just a couple of centimeters away from the transducer.

An active sound reinforcement system means more than just having amplifiers packed into a speaker housing.

Only when each single component such as high frequency drivers, midranges and woofers are controlled by individual DSP settings can the user benefit from this technology.

Scaling a line array is the most important aspect when talking about best performance and coverage. Where passive systems have limits in impedance load or number of amplifier channels, an active RCF sound system is freely scalable and individually controllable.




RCF develops advanced transducer technology including the application of high-tech materials such as Neodymium, Carbon Fiber, Pure Titanium, Kevlar, Kapton and Mylar hybrids. With over 60 years of design and manufacturing experience in the market, RCF has been instrumental in technological inventions such as carbon fiber cone molding, double silicon spiders, inside/outside voice coil windings to edge wound voice coil manufacturing and pure titanium diaphragm forming.

Our latest developments have resulted in designing state of the art neodymium magnetic circuits, radically new voice coil ventilation systems and ground breaking direct drive voice coil assemblies.





RCF’s original invention of the dual silicone sealed spider design offers many advantages: the two spiders offer double resistance to fatigue. The silicone between the cloth layers, being a very high memory material, provides the best shape stability to the spiders. The system, being sealed, functions as an air pump expelling hot air and drawing in cool air every time the cone assembly moves.






In our complex cooling designs individual components come together to create an ideal ventilation system. Finned cooling channels dissipate heat efficiently, the dust cap and the sealed spiders function as an air pump expelling hot air and drawing in cool air every time the cone assembly moves. Many openings are situated directly on the transducer’s side and on the rear plate.





RCF has developed a unique voice coil, combining the advantages of inside/outside technology to the superior quality of polyimideimide materials (wire resins and formers resins).

The inside/outside coil offers many advantages:

- The dissipation surface is doubled;

- The adhesion area to the former is doubled;

- During thermal expansion the Former is squeezed between inside and outside layers offering the best mechanical resistance.





The top of the former is bent and bonded directly to the edge of the titanium diaphragm resulting in a Direct Drive configuration. Direct Drive guarantees optimal transfer of energy between the voice coil and the dome assembly, providing smoother, extended frequency response beyond 10 KHz, reducing break up modes and lowering distortion. This assembly delivers high power handling along with excellent mechanical and thermal properties that make RCF neodymium compression drivers robust and reliable.





The HDL 50-A custom 4PATH designed waveguide allowsa 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 creates an ideal isophasic load from 700 Hz to the highest audible frequencies.





HDL 50-A features the unique RDNet interface, by means of which all components can be configured and controlled remotely from the front of house location for maximum system control. RDNet is a ‘daisy chain’ network based on the RS485 protocol, which is very stable and easy to use. An RDNet Control8 port is linked to the ‘Data Input’ of the first device, from which its ‘Data Link’ output is linked to the second device input and so on.

It is possible to link up to 32 devices to each port (max.256 speakers controlled simultaneously). When using Ethernet (through a dedicated switch), it is possible to link up to 20 Control8 per computer. Even extremely large systems can be easily organized and managed by RDNet. An innovative example is the recent large-scale installation of RCF speakers at the Baku Olympic Stadium in Azerbaijan.





A 4400 W peak power digital amplifier powers the HDL 50-A: 1100 W for the HF, 1100 W for Midrange section and 2200 W for the LF. New generation DSP handles all the processing within the cabinet and allows adjustment of Cluster size and HF projection.

All these setting are accessed by the encoder on the rear of the cabinets or using the integrated RDNet remote control. The easyto-access controls on the back of the speaker allow a number of simple optimizations to be carried out at the flick of a switch.




Finite Impulse Response filters. FIR filters offer a flat phase response starting from 250 Hz to 20 kHz. All frequencies are arrive at the ears simoultaneously and this provides correct impulse response with an unrivaled resolution and offset in depth.

The special algorithm for FIR filter’s creation permits to optimize the global latency introduced by the FIR to the system without sacrificing its filtering accuracy over all the audible frequency range.





Traditional sound reinforcement systems suffer from losses in high frequency sound due to air absorption at greater distances. RCF has developed an innovative algorithm to compensate for these high frequency loss in the system.

Special phase-neutral filters are used to achieve coherent distribution of sound for all listeners. Thanks to individual DSP settings in each module and the integrated network, this is achieved very easily and precisely.





Aiming the system is the most important pre-condition to get a proper working line array to achieve high reach and precise coverage. In each HDL 50-A line array module an inclinometer is built-in to give information about the real tilt angle of each cabinet via RDNet software.