KEF R5 LoudspeakerKEF R5 Loudspeaker and KF92 Subwoofer

A system with wonderful synergy.

With this article, Positive Feedback continues its content-sharing relationship with Enjoy the Music. Frank Garofalo shares his thoughts on the KEF R5 Loudspeaker and KF92 Subwoofer.

Dr. David W. Robinson, Editor-in-Chief

KEF is a company cherished in the audiophile world for bringing great sound to many around the world at all price ranges. KEF employs some of the industry's most innovative engineers and designers. KEF, in many ways, is one of the leaders in acoustic reproduction technology as KEF continues to push the envelope when it comes to perfecting loudspeaker design. KEF uses a combination of computer simulation, modeling, and measurement throughout its extraneous development process. Since most general computer applications are not suited for loudspeaker design as they are typically intended for use in other industries, KEF had to develop in house software of their own specifically for aid in designing loudspeakers. KEF has been doing this for a while and is one of the first, if not the first company, to measure a loudspeaker digitally with a computer in the seventies.

The company has a large portfolio of brilliant acoustic design patents that can be found in many of their products, all with the purpose of improving sonics. The KEF R5 belongs to the R series of loudspeakers. While the R series is not KEF's reference line, many Reference Series technology trickles its way down to the R series. The R series includes six models consisting of three floorstanders, one bookshelf, a center channel, and a Dolby Atmos surround. According to KEF, this new generation of R series speakers is a complete redesign and shares nothing in common with the previous R series besides the name.

Design

The KEF R5 contains the 12th generation of KEF's legendary Uni-Q driver which produces the mids and highs from a single point source. KEF's concentric Uni-Q driver is not to be confused with a coaxial driver configuration which is typical of a car audio speaker, where the tweeter is positioned in front of the woofer. In KEF's Uni-Q, the tweeter is fixated within the midrange driver, which should result in a more UNIform sonic presence.

The Uni-Q array is truly a complex arrangement that KEF continues to make improvements on with each iteration. In the latest generation of the Uni-Q that is featured in the R-series, KEF's engineers have made some significant improvements to the array that includes a completely redesigned midrange motor system.

In addition to the Uni-Q array, two 5.25" hybrid aluminum, sorry, "al-loo-MIN-ee-um" in British-speak, woofers take care of the lower end of the frequency range. The two bass drivers as well as the Uni-Q are color matched to beautifully blend in with the gloss black MDF cabinet. Two rear-firing ports can be found on the R5. Every part of the loudspeaker is meticulously thought out by the brilliant engineers at KEF, and the ports are no exception.

These are not just your average ports. KEF uses computational fluid dynamics to calculate the flare and profile of each port. This technology combined with a flexible port wall prevents resonance from impacting the overall sound quality of the loudspeaker. KEF even provides port plugs to control low-frequency output. Everything is encased within a strong solid cabinet that uses what is called "Constrained Layer dampened bracing" to minimize vibrations throughout the entire frequency range and dampen resonance.

Even the Grille has a lot of thought put into its design. Why drill unappealing holes into what would otherwise be a beautiful loudspeaker to hold a grille in place? Most of us would rather not stare at something so unappealing. Thankfully, KEF is aware of this, so they fit the R5 with a nice magnetic microfiber wrapped cover that fits the loudspeaker well that completes the R5's aesthetically pleasing design.

This aesthetics of the KEF R5 and KF92 paired together make for a very clean and elegant looking system that would blend in perfectly with any home's décor. Subwoofers are typically large and can be intrusive into ones living space but the KF92 is so compact it is able to fit in rooms without taking up too much space. Therefore, the R5 and/or the KF92 would be a perfect fit for a living space/small apartment. One thing you will notice immediately upon handling either of these two products is how solidly they are built. The KF92 is heavy for its size, a solid enclosure, a massive heatsink, two 9" drivers, and a 1000w amplifier do add up in weight. The finishes are done well, a clear reflection can be seen and is without the presence of any orange peel or other visual impurities. The R5 can be found in thee finishes: Black Gloss, White Gloss, and Walnut. Setup was fairly straightforward, although, I did have to make adjustments to my seating arrangement to compensate for the R5's short height.

So What Does All Of This Innovation, Technology And Brilliant Engineering Yield?

The KEF R5s and KF92 subwoofer working together in synergy to reproduce sound that is transparent, dynamic, and full of lifelike details throughout the entire frequency range with a strong, forward presence. The immersive soundscape that this system reproduces paired with hyper-realistic imaging is what really impressed me during the first listening session. The previous statement has a lot of weight coming from someone who owns a pair of Martin Logan ESL electrostatic loudspeakers, which are famous for having unique soundscape and imaging qualities. The R5 excels at throwing out a wide, encapsulating soundscape, but it does tend to lack a sense of significant depth in the soundstage. Individual Instruments and vocals are solidly present within a space that extends beyond the speakers without interfering with each other.

Every single note projected from this system had a seamless and uninterrupted path from the formation of the note, to the sustain of the note and to the decay of the note. The low end of the R5's without the KF92 is clean with the port plugs installed, without, the bass deepens and becomes more open and dynamic. Midrange and upper frequencies were absolutely full of detail and articulate but not bright or overbearing. Personally find myself able to listen for hours without any fatigue. The R5 does a good at being resolving, bringing you all the detail within a recording, all while being forgiving to recordings that are not of the greatest quality.

As is the case with most speakers, the KEF R5 greatly benefits from proper electronics. While a buffet of high-end components is not required, significant improvements can be seen when moving up in the food chain of amplification. This is proof of just how capable of a speaker the KEF R5 is! A grand total of four different means of amplification were used during this review. From my Marantz AV receiver to my higher end Ayre V5-xe. While the R5 was able to sound its absolute best when powered by my Ayre V5-xe.

The warmer 2-CHerry power amplifier by Digital Amplifier Company and the Rouge Audio Cronus Magnum II also provided desirable results, both of which are similar in price to the R5. It can be said without surprise that when powered by my Marantz AV receiver, the combination did not give an experience that would satisfy an audiophile. But would still be acceptable for home theatre use.

Small Sub, Big Wub

KEF's KF92 subwoofer packs two 9" drivers within a small ~14" x 13" x ~14" sealed enclosure. This is possible as the two drivers are positioned in a back to back force canceling configuration. Powering the subwoofer is a massive 1000W amplifier (each driver has 500W dedicated). A massive heatsink can be found on the subwoofer's rear to keep everything nice and cool. Setup of the KF92 was easy with the multiple placement dependent EQ preset you can switch between. There is an EQ preset for the room for when the sub is placed more towards the center of the room.

There's a Wall for when the sub is placed near a wall, corner, cabinet, and apartment preset can also be used when the sub is in their respective position. The feature works well, when placed in the corner of the room, the corner EQ preset tightens up and controls the bass. Throughout the review, the KEF KF92 floorstanding speakers were mostly left in the room or wall EQ setting. For $1999, it would be nice to see the KEF KF92 ship with a remote or have the capability to be controlled remotely via an app. This isn't that big of a deal but with so many new subwoofers coming on to the market with some sort of remote included its odd to see KEF not jumping on the boat.

The amount of bass that this little sub can throw down is genuinely impressive. Seriously, this little guy packs a punch. It is not just the quantity of bass that impresses me, the bass has some speed and is impactful. I mean, physically impactful. You don't just hear the performance; you can feel it. The improvement from the addition of the KF92 does not stop at the increase in bass performance. The KF92 opened up the soundstage that the R5s are already so good at reproducing. There was more space, more depth, and a more solid overall sonic presentation with the inclusion of the KF92. The same effect was heard when pairing the KF92 with my Martin Logan ESLs.

Great Value

KEF's extraneous engineering efforts in loudspeaker design clearly pays off when they are able to sell a highly capable product in this price range. At $2999.98, it can be safe to say that the KEF R5s are one of the best performers in that range. For someone who is shopping in this price range, it is truly great to see so much technology trickle-down from KEF's highly esteemed Reference series to the more affordable R series. KEF's KF92 subwoofer unifies the presentation of the entire system and greatly complements the R5 loudspeakers.

This system does a wonderful job with all genres of music and is forgiving when it comes to recordings that are not of the greatest quality. This is to be expected coming from one of the largest audiophile loudspeaker manufacturers who must cater to a larger consumer base with varying tastes. My time spent with this system will influence my next loudspeaker purchase.

Reference System

Speakers: Martin Logan ElectroMotion ESL
Amplification: Ayre V-5xe, Rogue Audio Cronus Magnum ii, Digital Amplifier Company 2-CHerry
Pre-Amplification: Ayre K-5xeMP
DAC: T+A Music Player, Geshelli Labs Enog2 Pro
Phono: EAR 834p
Source: Project Debut Carbon with an Ortofon Rondo Red cartridge, PC with Foobar2000 & Tidal
Cables: Nirvana Audio S-L series interconnects and speaker cable
Surround Processor: Marantz SR7012
Subs: SVS SB1000
Room:12' 6" x 13' 8" x 10' 2" (WxDxH)

KEF R5

Type: Three-way bass reflex loudspeaker
Uni-Q Driver Array: 1" vented aluminum dome tweeter centrally-mounted within a 5" aluminum cone midrange
Bass Driver: Two 5.25" hybrid aluminum cone drivers
Crossover Frequency: 400Hz and 2.9kHz
Frequency Range: 38Hz to 50kHz (-6dB)
Harmonic Distortion: < 0.3% 120Hz to 20kHz (90dB @ 1m)
Maximum Output: 110dB
Nominal Impedance: 8 Ohm (minimum 3.2 Ohm)
Sensitivity: 87dB/W/m
Weight: 60.2 lbs.
Dimension: 40.4" x 6.9" x 13.5" (HxWxD)
Finishes: Black Gloss, White Gloss, and Walnut
Price $2999.98 per pair