September 20, 2020 4 min read

Radian Audio Engineering developed a unique concept of using planar ribbon High-Frequency transducers in true coaxial drivers. Radian’s patent pending design pioneered the use of high performance ribbon driver in such systems. The advantage of placing a HF driver behind LF magnet system is well known. The HF is loaded on a waveguide that is comprised from an axisymmetric opening inside the center pole with expanding profile that smoothly transitions into waveguide section formed by LF driver cone.

Such designs provide exceptional acoustic gain for HF driver in its lower passband.



There is another advantage in this configuration. Both LF and HF drivers now comprise a single well integrated system with nearly coincident sources that can be summed in a single coherent points source providing very uniform dispersion over a wide coverage angle.

There are just too many benefits for coaxial drivers that can be successfully used in many professional, commercial and residential applications. The advantage of combining coaxial drivers with a planar ribbon is in the dramatically lower distortion than any other HF driver that uses a traditional motor with voice coil — where the significant inductive component and inherent asymmetries in the magnetic system, generate audible distortion.

To make things worse, most coaxial drivers on the market use compression drivers for their HF section. On top of distortion generated in the electromagnetic domain, compression drivers are notoriously prone to distortions related to the acoustic section — compression chamber and phasing plug.

When it comes to high performance applications where ultimate transparency and naturalness of sound is required, there is no substitution for Radian coaxial ribbon drivers.

Having a very smooth transition from center pole opening into cone geometry profile, Radian CR drivers provide exceptionally smooth SPL with very wide coverage. A very significant gain allows planar ribbon driver to be crossed over at a low 1.5 kHz point, ensuring proper integration of LF and HF sections.



The Radian CR line consists of four models, 6.5-inch, 8-inch, 10-inch, and 12-inch drivers. The same HF ribbon driver is used in all four models to ensure similar matching sonic characteristics and the possibility to mix and match these drivers depending on application. A larger waveguide is provided as each LF cone size increases, adding significant gain to HF output and thus allowing to use the same HF driver across the entire line.

Common characteristics of this new Radian CR line are its exceptional sonic transparency, midrange coherency and even dispersion over coverage area. Each driver has its own optimized XO network making installation easy.

In the past, such drivers were primarily used for studio monitors and high end home systems, because of its superior sonic presentation, especially in the vocal range, combined with an almost unheard of transparency that allowed us to look “into” a recording. The Radian CR drivers inherit those traditions, have very high sensitivity and can be used for demanding high performance home systems when augmented with a woofer or subwoofer. Studio monitoring is a very special application and we encourage you to consider using coaxial ribbon drivers to hear the difference. Very often, recording and mastering engineers experience too much of a room influence or other effects of the environment that may impart their effects on recorded sound. Having a coherent point source system with very even and constant dispersion helps to reduce effects that a recording facility may have and obtain a more consistent sound from your monitors. The same goes for any other application where speakers are in close proximity to room boundaries. Such effects cannot be overstated. They can be very detrimental to overall system performance and can reduce or sometimes completely negate investment put into the system.

Our first hand experience with home cinema and other residential applications, using these drivers, shows that they can rival any top solutions used in the custom installation market. 

The Radian 6CRS5130 and 8CRS5130 models have proven to be a winning solution when it comes to new immersive home cinema formats. The key to proper reproduction of all those formats is in having high output, wide dispersion drivers with similar sonic characteristics. Radian CR drivers are just that.

Radian 12CRS6430,  12” drivers, are used as surround speakers in premium commercial cinema installations in theaters up to 200 seats. Radian 10CRS6430,  10” drivers, are used in rooms with up to 100 seat capacity. In all those applications they withstand very rigorous tests that are required by new commercial surround sound formats.

For home cinema and other residential applications we would recommend the Radian 6CRS5130 and 8CRS5130 drivers.  A simple solution for any home theater could be using those drivers all around for all channels. Surrounds channels may have a single coaxial driver with bass managed at 80Hz or 100Hz. A screen channel may have similar or slightly larger in size driver, augmented by single or two LF transducers for a full range system. Such a system, using all Radian CR drivers, is in fact be an ideal immersive audio system with precise coverage and nearly identical sonic performance coming from every speaker in the system.

Even though the depth of the Radian 6CRS5130  (6.5”), the smallest model, is larger than of a typical shallow in-wall speaker, very often when it comes to custom home theater, one could accommodate the 4.5” driver depth by having a slight wall protrusion using a custom built grille bezel. 



If in-wall space is limited by a 2x4 stud bay without any chance for beyond wall protrusion, CR drivers can be used exclusively for ceiling channels. Unlike most consumer speakers, Radian CR drivers have much higher output capability and offer compression free performance with exceptional dynamic range.

When it comes to commercial applications, we recommend our customers to look for available Lowell or Atlas hardware, plates and UL approved metal back boxes if plenum rated speakers are required. Speech intelligibility and listening comfort within a sonic scape created in a modern commercial environment is a requirement today. The low distortion and exceptional transparency of Radian CR drivers provide comfortable listening and communication environments in any commercial space. 

Radian Audio Engineering always supports our customers helping to find the best and technically optimum solution for each project. We also offer complete custom system fabrication for  special cases if required.


Copyright ©2020, Igor Levitsky. All right reserved.

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