KEF R Series 5.1.4 Dolby Atmos Speaker System Review

It’s been well over a year since Dolby introduced Atmos for the home, and today you’ll find the feature included in AVRs and pre/pros at virtually every price point. Atmos is capable of rendering a three-dimensional soundfield by adding elevation channels to the surround-sound experience. Currently, Dolby has the market for immersive audio almost entirely to itself, with dozens of Atmos titles already out on Blu-ray and many more on the way.

There are two ways to implement an Atmos-enabled speaker system. The first is to install speakers inside (or on) your ceiling, and the second is to bounce sound off the ceiling using dedicated, upfiring Atmos speaker modules or Atmos-enabled speakers that have the modules integrated within them.The KEF R Series system featured in this review utilizes the reflective Dolby Atmos approach to immersive audio. In this instance, four R50 Atmos modules rested on top of the ear level speakers—a pair of R500 towers and a pair of R100 bookshelf speakers—and reproduced the elevation channels.

KEF concentrates on designing and building stylish, high-performance speakers, so it’s no surprise that the R Series looks fantastic. However, in order to justify the cost of the system—$8900 as reviewed—it had better perform at a high level as well as look good. Read on to find out how the KEF R Series fared.

Features

KEF is rightly proud of its signature 2-way, concentric Uni-Q driver that nestles an aluminum-dome tweeter at the center of an aluminum mid/woofer, making them time and phase coherent. Notably, all speakers in the review system utilize the Uni-Q.

The R Series 5.1.4 Atmos system in this review consisted of five different products: Two R500 towers ($1300 each), dual R100 bookshelf speakers ($1200/pair), one R200c center ($1000), four R50 Atmos modules ($1200/pair), and one R400B subwoofer ($1700). The review speakers came in a gloss-black finish, but they are also available in gloss white, walnut, and rosewood.

The R500 tower speaker features a rear-ported 3-way design with dual 5.25″ aluminum woofers and a Uni-Q driver that combines a 5″ aluminum midrange with a 1″ aluminum tweeter. The speaker’s rated frequency response extends from 46 Hz to 26 kHz (+/-3 dB). The speaker cabinet measures 42″ x 11.8″ x 12.9″ and weighs 48 pounds.

Crossover points for the R500 are 500 Hz and 2.8 kHz, and the tower’s nominal impedance is rated at 8Ω (minimum 3.2Ω), with sensitivity specified as 88 dB dB/W/m. KEF recommends an amplifier with between 25 and 150 watts of power, and the speaker’s maximum rated output is 111 dB. Each speaker is equipped with terminals that allow for bi-amplification and features integrated feet with spikes.

KEF’s R100 bookshelf speaker is a rear-ported 2-way design with a Uni-Q driver featuring a 5.25″ mid/woofer and a 1″ dome tweeter. The rated frequency response of this speaker is 56 Hz to 28 kHz (+/-3 dB). The speaker enclosure measures 11″ x 7.1″ x 11.4″ and weighs 14.5 pounds.


The pair of KEF R100 bookshelf speakers that I used as surrounds.

The R100’s crossover point is 2.5 kHz, and the nominal impedance is rated at 8Ω (minimum 3.2Ω) with a sensitivity of 86 dB dB/W/m, and the speaker’s maximum rated output is 107 dB. KEF recommends an amplifier with between 25 and 100 watts of power, and the speaker terminals support bi-amplification.


KEF’s speaker terminals that allow for bi-amplification.

A KEF R200c served as the center channel for the system. It’s a ported 3-way design featuring dual 5.25″ woofers and a Uni-Q driver with a 5″ midrange and a 1″ tweeter. The R200c’s frequency response is rated at 65 Hz to 28 kHz (+/-3 dB). The R200c’s enclosure measures 6.7″ x 20.9″ x 12 and weighs 31.7 pounds.

Crossover points for the center are 500 Hz and 2.8 kHz, and the R200c’s nominal impedance is rated at 8Ω (minimum 3.2Ω) with a sensitivity of 87 dB dB/W/m. KEF recommends an amplifier with between 25 and 150 watts of power, and the speaker’s maximum rated output is 111 dB—it can keep up with the R500 towers. The R200c speaker is equipped with terminals that allow for bi-amplification.

Next up are the R50 Atmos reflected-sound modules—the system included four of them serving as elevation channels. These modules are a perfect aesthetic match for the R500 towers and R100 bookshelf speakers, sitting directly on top of those speakers. The modules feature a sealed 2-way design and use a Uni-Q driver with a 5.25″ mid/woofer and a 1″ tweeter.


KEF R50 Atmos modules, seen here with and without magnetically-attached cloth grills.

The R50’s crossover point is 2.5 kHz, and its nominal impedance is rated at 8Ω (minimum 4.8Ω) with a sensitivity of 85 dB dB/W/m. KEF recommends an amplifier with between 25 and 100 watts of power, and the speaker’s maximum rated output is 106 dB. Cabinet dimensions for the R50 are 6.9″ wide x 7.1″ deep x 10.2″ high, and the module weighs 9.9 pounds.

Last but certainly not least, the R400b subwoofer is a dual-opposed sealed design that uses twin 9″ aluminum drivers. Total rated power is 500 watts thanks to dual 250-watt class-D amplifiers—one per driver. The R400b’s maximum output is rated at 111 dB, and its rated frequency response is 26 Hz to 140 Hz (-6dB). This compact sub measures a mere 14.4″ high x 13″ wide x 13.8″ deep (the enclosure itself is a perfect 13″ cube) and it weighs 47 pounds.


The R400b dual-driver force cancelling subwoofer.

The R400b’s dual-opposed driver configuration provides the benefit of force cancellation, which virtually eliminates unwanted vibrations—when you feel the bass, you know it’s not just the floor shaking. The sub includes stereo RCA line-level inputs as well as speaker-level inputs. It also sports a phase switch, a selectable EQ switch (0 dB, +6 dB, and +12 dB), a variable crossover dial, and a volume knob. The R400b is probably the smallest high-end subwoofer I have ever used in a full-sized surround system.

Setup

I followed standard operating procedure when setting up the system, placing the speakers in a classic 5.1 configuration. Atmos-enabled reflective speakers and modules work with most rooms that have a flat, acoustically reflective ceiling, such as the one in my 11′ x 19′ x 9′ studio.

I used a Marantz SR7010 AVR for Atmos processing, room correction, power for the R50 modules. For the five ear-level speakers, I used a 200-watt-per-channel Classé Sigma AMP5 to provide ample power. The R500 towers served as front left and right channels, and the R100 bookshelf speakers performed surround duty. As you’d expect, the R200c served as the center channel, while the R400b subwoofer handled deep bass.

I connected each speaker—including the R50 Atmos modules—to the matching outputs on the SR7010 and AMP5 using 12-gauge Monoprice speaker cables. Next, I set up the SR7010’s calibration microphone and selected the appropriate speaker configuration in the AVR’s menu: 5.1.4, with Atmos-enabled speakers. Finally, I started the Audyssey XT32 auto-calibration routine.

When Audyssey finished, I reviewed the settings to make sure there were no obvious issues. I made a couple of small adjustments, such as increasing the subwoofer’s output by 3 dB—I like a bit more emphasis on the low end than what Audyssey prescribed. I also changed the front left and right speaker size setting from “large” to “small” and assigned a 60 Hz crossover to the R500s, thus matching the 60 Hz crossover point the system picked for the R200c center. Audyssey set the crossover for the R100 surrounds to 90 Hz and the R50 Atmos modules to 110 Hz, and I kept those settings.

Performance

Subjectively speaking, I was utterly thrilled with the performance of the R Series Atmos system. It delivered a top-tier immersive audio experience and looked good doing so. Perhaps it’s the timbre-matched, time-aligned, and phase-coherent nature of the Uni-Q drivers that allowed the system to totally disappear, but there was no question it exceeded my expectations.

I was surprised to find that the output of the KEF system felt energetic in a way that I usually associate with pro audio gear. With a good recording, you can feel the music. When I turned up the volume, the system didn’t strain, I didn’t hear distortion, and there was no obvious sign of dynamic compression—right up to the point where the system was maxed out. I found the output of the KEF system sounded very consistent, regardless of where I set the volume knob.

My benchmark for Atmos-system evaluations are the Blu-ray demo discs provided by Dolby at trade shows. The latest version of the disc came from CEDIA 2015, where I attended a significant number of Atmos demos. Furthermore, I’ve played the Dolby trailers from the disc at home on various Atmos-enabled speaker systems—it’s as close to a standard reference as I’ve got.

The KEF system rendered Atmos effects from Dolby’s trailers with precision; to my ears, the soundfield was seamless. The sense of sounds coming from and moving around overhead was as distinct and well rendered as anything I’ve heard coming from a reflected-sound Atmos system. When compared to in-ceiling speakers, the overhead soundfield tends to be a bit more diffuse, but sometimes that quality is actually an advantage—think room ambience, echoes, rain, wind, etc. Even so, I could also track individual overhead sounds—think helicopter, a fly buzzing around, or birds in a forest. The point is, the Atmos part of the speaker system worked as it’s supposed to.

I also used the KEF R Series Atmos system to watch a number of movies with Atmos soundtracks on Blu-ray. They included Mad Max: Fury Road, Insurgent, Mission Impossible: Rogue Nation, The Man from U.N.C.L.E, San Andreas, and the remastered Bram Stoker’s Dracula. I had a blast watching them all, and frankly, I had to force myself to acknowledge the speaker system, because most of the time, the immersion was so complete that I was simply lost in the movie. I did not hear anything that would hint that I was listening to reflected overhead sound instead of well-integrated in-ceiling speakers.

There were a couple of instances when I found the performance limits of this particular R Series system. Invariably, that limit involved the R400b subwoofer—I’d wind up maxing it out when watching movies with a lot of (very) deep bass, such as Olympus Has Fallen and The Avengers. Although it was very graceful when it approached its limit, I found myself bumping up against the subwoofer’s peak output when I pushed the system really hard.

Going with the Audyssey default subwoofer level setting instead of boosting it by 3 dB bought me some more headroom, but at the expense of the visceral bass I like. I’m used to running dual JL Audio e112s as reference subs, so I’ve grown a bit spoiled when it comes to bass reproduction, and I’ve always been a multiple subwoofer kind of guy—25 years and counting.

Aside from the fact that I love bass so much that I can’t get enough, the reality is the R400b sounds tight, accurate, powerful, and most importantly invisible to my ears—I was never able to localize it. Again, I just wish I had requested two of them for the review. As an experiment, I ran the KEF speaker system with the twin JL e112s handling bass, and I found that combination extremely compelling; I would expect something similar from dual R400bs.

KEF’s R Series speakers are very musical, and I found great pleasure in using the Atmos Dolby Surround upmixer to play a wide variety of tunes. With music, the R400b sub never broke a sweat. The sound was tight, accurate, and detailed—it’s some of the best audio fidelity I’ve heard from a review system. No matter the genre— jazz, hip-hop, reggae, dubstep, rock, even orchestral music—the KEFs rendered lively, deep, detailed sound that consistently put a smile on my face. Impressively, I completely forgot that I was listening to only one compact subwoofer whenever I was listening to music.

Conclusion

I’m happy to say that the KEF R Series system lived up to the company’s reputation for making exceptional speakers. In terms of both aesthetics and performance, the system ranks in the top tier among those I have auditioned. The use of Uni-Q drivers in all the system’s speakers pays clear dividends in terms of the level of immersion it achieves.

The key to the system’s appeal is how simple it is to set up, how absolutely smashing it looks, and how well it works with Atmos content. Of course, the system requires a room that meets Dolby’s guidelines for reflected-sound elevation channels. When used in such a space, the fidelity it delivers is truly top notch and worth experiencing.

If you’re interested in achieving maximum decibels per dollar—aesthetics and speaker cabinet size be damned—then this might not be the right system for you. However, if you can afford the refined engineering found in KEF’s R Series, and you appreciate speakers that squeeze very high performance into a relatively compact yet strikingly stylish package, you will be richly rewarded with the immersive audio environment that a KEF R Series 5.1.4 Atmos speaker system creates.

REVIEW SYSTEM

Processing and Amplification

Marantz SR7010 AVR
Classé Sigma AMP5 5-channel amplifier

Sources

Windows 10 PC
Samsung BD-H6500 Blu-ray player