KEF R8a Review: The perfect Dolby Atmos speakers

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Over the past years, the KEF R Series has enjoyed consistent popularity among brand fans. Having evaluated the potential of this category of acoustics, the company decided to make the R-series even better, bringing it as close as possible in terms of characteristics to the top Reference line.

The company claims that KEF was the first to apply such a number of technological solutions and achieve such a high quality of reproduction in acoustics of this price category. Once again, we note that the loudspeakers of the new R-series are not updated speakers compared to the models of the previous generation, but completely new devices: the number of changes made to the design of these loudspeakers is 1043!

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At the heart of the design of the models of the new line is the proprietary 12th generation Uni-Q driver, which is equipped with a new motor system to improve sound at mid frequencies. In addition, the developers paid great attention to the influence on the sound of the gap between the HF and MF diaphragms of the Uni-Q, which should be minimal, but can expand at certain resonant frequencies.

The new structure and special damping behind the tweeter eliminate these resonances, resulting in softer, more transparent and detailed high frequencies.

As with other KEF loudspeakers, the Uni-Q module’s midrange serves as a kind of waveguide for high frequencies, but in the models of the new R-series, in addition to this, a special Ring Flare was used: it radically reduces the influence of diffraction effects that occur on the edges of the speaker box. As a result, the sound of the speaker system becomes much cleaner and more transparent.

For the new R Series, KEF has developed woofer drivers that enable high quality bass reproduction when used with smaller speaker diameters; the latter was necessary to make the front bezels of the loudspeakers narrower, in line with current design trends. The new woofers have longer travel, a low-distortion motor system and a stiffer diaphragm.

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The new R-Series uses the Constrained Layer Damping system, which provides additional damping for the anchoring points of the struts to the speaker cabinet walls. This method effectively dampens unwanted vibrations.

As you know, bass-reflex acoustic design allows a loudspeaker to reach lower frequencies, but often creates problems due to turbulent noise and port resonances, which usually “creep out” in the mid-frequency range.

Therefore, KEF engineers faced a new task – to somehow level the weaknesses of the phase inverter design, while preserving its positive aspects. To find a solution, the KEF R&D department used computational aerodynamics and FEA (Finite Element Method) methods to test many options for bass reflex systems and settled on the original design. The port has specially shaped bells at both ends to eliminate air turbulence and reduce lateral resonances. The pipe walls are made of flexible material to combat the longitudinal resonances of the port.

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Another important innovation in the KEF R Series speaker is the suede-look microfiber grills. For each speaker, 1801 holes are made in the grill, which minimizes the effect of the grill on the sound of the speakers and provides a high degree of protection for the cones. The speaker design of the new R Series deserves a special mention. These loudspeakers have slimmer cabinets with narrow bezels. The acoustics are available in three color finishes – black lacquer, white lacquer and walnut veneer. The speaker cones, speaker feet and brand logos are all in the same color as the speaker cabinet – a first for this.

The new 2018 KEF R Series includes the R11, R7 and R5 floor standing models, the R3 bookshelf speaker, R2c center speaker, and R8a, a dedicated speaker module for Dolby Atmos.

The R-Series is well suited to handle the new 3D sound formats as it includes dedicated KEF R8a speaker modules designed for overhead mounting on front and rear home theater speakers.

The KEF R8a speakers are designed for Dolby Atmos reproduction and are installed over existing front and rear speakers. The vertical dimension is essential for the breathtaking effects Dolby has achieved in theaters. Built around a state-of-the-art UNI-Q module (25mm vented tweeter and 130mm woofer), the speaker radiates sound upward, enveloping you in a faithfully reproduced field in which the sound sources move as in real life.

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The KEF R8a loudspeakers have an improved damping system for the aluminum dome tweeter, resulting in improved low-frequency reproduction. KEF not only applies computer calculations to calculate crossover circuits and match driver pairs, but even the air movement through the bass reflex ports has been optimized using CFD.

Conclusion

Equipped with a single Uni-Q driver, these loudspeakers are directed towards the ceiling to create a special vertical dimension and to convey the effects inherent in the new Dolby Atmos format. The model received a closed case, which looks like a concert stage monitors. This speaker weighs 4.5 kg. Separately, the company pays attention to the possibility of mounting these Atmos speakers on the walls.

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