One quiet afternoon some eight or so years ago, I got a call from Simon Ashton. Young, enthusiastic and oblivious to the perils of the audio industry, he told me he’d designed a new pair of loudspeakers. As editor of a popular British hi-fi magazine, I got plenty of such communiques at that time but it was his passion – and the fact that his speaker had a ribbon tweeter – which caused me to investigate further. The world and his dog were (are) all brilliant speaker designers you see, and I’d regularly be told by callers to the magazine that every new MDF box with bought-in drivers was revolutionary, and how I just had to review it. The Kensai however, really was different…
Originally launched for £1,999, this loudspeaker is made in Kent, and very well too, it transpired. Indeed, its fine cabinetry proved very well damped and unresonant, whereas the detail work was excellent. The treble driver interested me, being an isoplanar ribbon with an effective area equivalent to 2.5 times that of a conventional dome, according to Audiosmile. Simon Ashton noted that, “The majority of standard ribbon tweeters have very high distortion and small surface area, which produces the typical shiny sound and necessary high crossover point resulting in poor driver integration. The Kensai ribbon is quite the opposite, having the lowest distortion of any tweeter of which I’m aware, and a large surface area, allowing a low crossover point and good integration with the mid/bass unit.”
The tiny a 120mm bass/midrange driver is also an interesting piece of work. It uses a magnesium alloy cone, “chosen for having the lowest distortion of all units I tested, while at the same time having excellent headroom and bass extension for such a small item”, says Ashton. “I generally don’t like metal cone woofers because they exhibit a break-up peak which adds a hard edge to the presentation. The Kensai woofer is small and stiff enough that this peak is twice as far out-of-band as a typical 6” driver, so the sound remains clean and natural throughout the range.”
The crossover is phase aligned and utilises high quality components, with the transition being made at 2.2kH. It is not biwirable, the company choosing to fit a single set of high quality binding posts per speaker. The bass port is aperiodically loaded to reduce woofer movement below its useful range. The finishes at launch were Beech and Walnut with black or white leather neatly and continuously wrapped over the front baffle and rear panel, and fixed out of sight within the confines of the slot port. AudioSmile claim low 83dB efficiency, so the Kensai is insensitive and requires a powerful transistor amplifier to produce serious levels.
Indeed, this is the biggest issue with the speaker. The later MkII Kensai got a more efficient mid/bass unit and a redesigned crossover, which Ashton claims makes the speaker useable even with valve amplifiers, but this first example of the breed is extremely power-hungry and you’ll need the thick end of 100W RMS per channel at the very least. Being so small, it will never work in a large room convincingly – but give it some serious power and a medium sized room, and it’s surprisingly convincing…
Properly set-up, this little AudioSmile is one of the best small speakers I have heard. Unlike most, it’s very musical; you can hear the company demonstrate it at hi-fi shows playing loud reggae music (yes, really!) and it’s infectiously enjoyable. Bass is highly tuneful, and it integrates superbly with a bouncy midrange that just wants to jump from one beat to the next. Not only this, but it’s surprisingly transparent too – thanks in no small part to that superb tweeter. Treble is superb, being wonderfully delicate, finely resolved and super-smooth. You’ll struggle to hear better under £10,000 in this respect.
Because of the Kensai’s intrinsic rightness, the soundstage is also handled very well – again credit goes to the isoplanar ribbon. Those tiny cabinets dissolve and the the speaker throws out a far larger sound than you’d expect, right across all three dimensions. It makes popular benchmarks like the LS3/5a (and its ilk) sound dull as ditchwater, congested and boring. The only caveat is that this speaker isn’t brilliant at dynamics; it tracks them well, but cannot defy the laws of physics and when given the full weight of a symphony orchestra at highish volumes, tends to compress things a bit. That said, it’s excellent with those all-important ‘micro dynamics’ – the nuances of musicians’ playing – which are so vital.
Overall them, a fascinating little loudspeaker and one that’s less popular than perhaps it deserves to be. AudioSmile is not a large company with a big marketing budget, which is why most people simply never get to hear the Kensai. If they did, I suspect it would be one of the best selling small speakers around – and rightly so.