1.*What does Kensai stand for?
The word Kensai is Japanese and can be translated in a number of ways. I take it to mean a small but great source of power, something with much aura. It is generally applied to a person, but needn't be limited to that. The word Kensei (note spelling) also exists and means sword saint; a title given to the most skilled warriors. There is some crossover between these words as no precise rules exist for romanisation of the language.
2. To whom would the Kensai be most suited? (music tastes, room size, amplifier type, etc.)
Originally the Kensai was designed for my mother! She loves music and appreciates quality sound, but has no interest in hi-fi as a hobby. As such, the design criterion were simple, it must be as small as possible and sound as good as possible. Anybody who prioritises good sound above equipment bragging rights should enjoy the Kensai. It plays all types of music equally well as this was a very important factor for me when designing the speaker. The Kensai will fill a larger room than one might expect, but maximum playback level won't be at rock concert levels. It will happily work in a room about 4m by 6m or less. The impedance does not peak high nor drop very low, so all amplifiers will find the Kensai an easy load to drive without needing large amounts of current but the Kensai's low sensitivity does require a reasonable voltage swing. To give a less technical explanation a typical solid state 50-watt amp will do well. I use a Cyrus integrated.
3. Is the Kensai designed and built in the UK?
The Kensai is about as British as a product can get these days. They are designed, machined and assembled in the UK. In fact only the tweeter (American), woofer (Norwegian) and capacitors are made outside the UK. Even the cardboard box is British.
4. Is there a specific reason for the 150x250x200mm size of the cabinet?
The Kensai was made to be as small as possible while sounding as good as possible. This meant the first job was to simulate a number of high quality small woofers and find the smallest cabinet that could still achieve reasonable bass extension a little below 50Hz. The 5 litre cabinet of the Kensai is the result. It seems to fit on most bookshelves, unlike many so called bookshelf speakers!
5. What type of high frequency unit does the Kensai use and why?
The speaker employs an isoplanar ribbon unit. Although commonly classed as a ribbon, it is closer to the workings of an electrostatic. A Kaladex (high-tech plastic) diaphragm has what are essentially circuit board traces etched on it and these conduct the music signal. Strong magnets are then positioned across the front and back of the unit in a push-pull fashion. Etching the conductive pattern on to the diaphragm allows the magnetic field to be picked up from the most linear areas of magnetic field, unlike a traditional all-aluminium ribbon. The majority of standard ribbon tweeters actually 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-woofer. This is a primary reason the Kensai can play all genres of music.
The original prototype Kensai was made using a high quality soft dome tweeter which sounded very nice for gentle music but became slightly confused with metal and rock. The isoplanar ribbon on the other hand, cut right to the heart of everything I threw at it.
6. What type of mid/low frequency unit is used and why?
The mid-woofer is a magnesium alloy unit which was 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. 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.
7. Can you describe what Aperiodic (Aperiodic Damped Front Slot Resonator) means in the context of the Kensai?
This is the type of porting the Kensai uses. The narrow but wide slot resonator (port) gives a lower Q resonance than a typical tube port, so it doesn't 'thump' at a specific frequency like a lot of small speakers. Aperiodic damping is a method that in this case reduces the woofer's movement below it's useful extension. A normal port will act like an open box below it's resonance, meaning the woofer will jump around excessively with such signals. Additional air restriction in the Kensai slot resonator means the woofer doesn't move when it doesn't need to, reducing modulation of the mid-range frequencies.
8. Why single wired, and not bi-wiring at the rear with the binding posts?
I see bi-wiring as a tactic to sell more wire. The theory of bi-wire is to limit electrical currents that should return to the amp, going to the tweeter instead. This is done by having a separate ground wire for each driver going to the amp. However, both negative connections still return to a single point at the amplifier, so why not have this singular point inside the speaker? This is the theory of star grounding where all return signals in the circuit individually go to a single point. I always prefer intelligent rather than excessive engineering.
9. Who designed the Kensai (electrically) and (Industrial design)?
AudioSmile is basically me, Simon Ashton, although I occasionally call on others when extra hands are needed. My educational background is in sound recording and my hobby was always listening to music. I suppose it was around the time of studying that I became aware of the great kick which comes from upgrading one's music system. During my studies I became very interested in acoustics and continued to teach myself in this area. The number of small professional recording studios is decreasing all the time with the popularity and affordability of home recording. So, rather than struggling to find a first job in a studio, it seemed a logical progression to take my hobby and passion to the next level and make a business from it. That was about 4 years ago, and I'm happy to say AudioSmile is still growing now!
