In the June 2020 edition of Voice Coil magazine, Vance Dickason measures in detail the latest Radian Audio Engineering’s LT6 Horn-Loaded Ribbon Device.
Radian is a pro sound driver OEM well known for its great sounding compression and coax drivers, several of which have been featured in Test Bench over the last several years, including the 1.4” 835PB ferrite magnet and aluminum diaphragm compression driver featured in the February issue of Voice Coil magazine. However, the sample Radian sent for this Test Bench article was neither a compression driver nor a coax, instead it is one of its new waveguide planar transducers, the LT6 shown in Photo 1.
Intended to be a more hi-fi substitute for 1” compression drivers, the LT6 and all of the other new Radian ribbon high-frequency devices were designed by 35-year loudspeaker engineering veteran Igor Levitsky. Levitsky began designing planar ribbon drivers and speakers in the former Soviet Union in 1986 as a young engineer after graduating from Kiev Technical University in electroacoustics.
Beginning in 1995, Levitsky worked with Hi-Vi Research, where he developed a complete production process for manufacturing ribbon diaphragms. Over the next 20 years, Levitsky developed planar ribbon drivers and speaker systems for the consumer market for BG Radia (acquired by Christie Digital in 2014) and for the pro market with SLS Audio (acquired by Dolby in 2014). Levitsky also worked with OPPO and Dai-Ichi on the development of the award-winning OPPO PM1 and PM3 planar magnetic headphones. He joined Radian Audio Engineering in 2018 with the goal of bringing the latest planar ribbon technology innovations to the pro sound market. Levitsky holds a total of six patents on planar ribbon driver and speaker design.
SoundCheck CSD waterfall plot of the Radian LT6.
Features for the LT6 waveguide ribbon transducer include a FEA-optimized neodymium magnet motor structure, Kapton diaphragm, a continuous power handling of 40 W AES with a 150 W short-term IEC power handing, a 1.7 kHz to 2 kHz recommended crossover frequency (with a minimum 12 dB/octave high-pass network), and a 1 W/1 m 103 dB sensitivity (average output across the operational frequency range with the LT6 waveguide). The LT6 waveguide directivity is 100° × 40° and is optimized for line arrays.