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This review first appeared in the November 2011 issue of hi-end hifi magazine fairaudio.de of Germany. You can also read this review of the Kef Q900 in its original German version. We publish its English translation in a mutual syndication arrangement with the publishers. As is customary for our own reviews, the writer's signature at review's end shows an e-mail address should you have questions or wish to send feedback. All images contained in this review are the property of fairaudio or Kef - Ed.

Reviewer: Ralph Werner
Sources: Luxman D-05, Logitech Squeezebox 3, Readynas Duo, Benchmark DAC1 USB, Acoustic Solid MPX, Phonotools Vivid-Two, SME M2 12", Denon DL-103, Ortofon MC Bronce, Zu Audio DL-103, SAC Gamma Sym
Preamplifier: Octave HP300
Power amp: Electrocompaniet AW180
Integrated amplifier: Denon PMA-2010AE
Loudspeakers: Ascendo System F, Thiel SCS4
Review component retail: €1.798/pr


Any profession entails a certain deformation. By that I don’t mean a construction worker’s calluses or the desk jockey’s equivalent posterior. I mean a type of mental thick skin from doing a particular job for too long. If asked what part of my hifi cost me about  €1.500 for example, I’d have to really think about it today. I'd eventually point at the interconnects with an earnest  “those sound a lot better than the low price suggests" explanation. That's before noticing of course that unless I was talking to a certifiable high-end crazy, I’d have already set off mental alarm bells with the questioner.


The high-end reviewer counters such snobbery deformation by dealing with relatively affordable kit  Relative is vis-à-vis having turned green with jaded from the cost-no-object creations of audiophilia. Then one suddenly encounters surprises about what’s possible for a mere fraction of such budgets. Whilst I had zero expectations about Kef’s Q900 loaner from sheer unfamiliarity, I did somehow anticipate a rather smaller shipping carton. Once unpacking and setup had me eye to eye with eight (!) 8-inch drivers, the surprise compounded. Granted, this predicted as yet nothing about the sound. But I’d clearly seen a lot less material excess for the given coin.
"Designed and Engineered in the UK" it says proudly on the carton – and in ten times smaller type “Made in China". Funny. Perhaps this reflects what's now considered a perfect given in this price class. And why then highlight the obvious? The Q900 is the largest floorstander in the ‘New Q Series’ which includes two monitors, three towers, two centers, a subwoofer and one rear dipole (the precursor of this speaker family remains current as ‘Classic Q Series’).  At 1.1m height the Q9 is all fully grown up. Since it sounds to match, a bit of space is in order. A 15m² listening cabin would be too skimpy. But more on that anon. First basic tech.

Here brevity shall suffice. For the 10-course spread Kef’s very comprehensive website already offers unusually long white papers, plenty of graphics, videos, 14-page PDF downloads and such. So, starting at the front, top to bottom, one spots...
 
Very unusual but clever terminal arrangement: Turn the central knobs clockwise until the marker appears (see left knob) and the Kef Q900 operates in bi-wire mode. In the other direction the inputs are bridged for single wire.
1/ the Uni-Q coaxial driver of a sizable dome tweeter surrounded by the aluminium diaphragm of the mid/bass unit
2/ below an associated passive radiator that’s housed in the same sub enclosure
3/ the active woofer
4/ and an associated passive radiator once again sharing a common chamber.


Did this settle the obvious? Since drivers 2 through 4 look utterly identical, it’s easy to get confused. To be clear then, the Kef Q900 is a 2.5-way affair. Separation between treble and midband occurs at 1.800Hz. The vocal range is thus handled by the coaxial’s big surface. This extends unhindered into the bass where it parallels the dedicated woofer to, peu à peu, fade out mechanically not via a high-pass filter—there is none—but as it is implied by the driver’s resonant frequency and the air volume it loads into. The lowest bass is handled by just the woofer. This implies greater than usual overlap between bass and midrange to support a more homogenous blend. The counter argument would cite increased interference issues from broader joint coverage of the same band by multiple drivers.


The same can and is usually said against 1st-order filters whose shallow slopes additionally put greater demands on any given driver’s edges of its bandwidth. Incidentally Kef does rely on exactly such filters for better phase response than steeper networks and because a lower crossover parts count nets greater dynamic transparency if one uses appropriately capable drivers. It’s that rather than the filter which, so Kef, creates the true challenge with a minimal filter network.

As stated already, the Kef reaches to 1.1 meters. Its about 25cm width doesn’t make it outright slim either. Add to this cosmetic profile the outriggers which claw into the floor plus four big drivers per side and things don’t get any more feminine even with the included grill. This is really more a man’s speaker than a beating-heart beauty. Inspecting the box up close one notices a few items.


1/ Round is so yesteryear. Contrary to the Classic Q predecessors, the swooping cheeks are no more. Kef doesn’t cite cosmetic reasons for the return to flat sides but a ca. 30% larger internal volume for the same footprint which benefited bass pressure and extension.


2/ There is no port. This is a sealed box. Of sorts. The presence of two passive radiators technically makes it ‘semi’ sealed since those radiators work similar to a bass reflex system. Whilst the latter has the air column inside the reflex tube resonate, the former simply shift that action on the passives. The price to pay is obvious. Even a passive driver is costlier than a plastic tube. The advantage is an absence of flow noise which higher volumes can elicit from ports. Here there is no flow. Radiators also minimize midband leakage which can undermine overall transparency and becomes more relevant when a big Uni-Q driver handles the higher bands.


3/ For real veneer the budget was too tight. Even so the top cover isn’t plastic but recycled and stained wood fiber. It looks fine but not particularly luxurious at that.