Since the above review the Kantus have been subject to continuous improvement. Although the outer cabinet shape has remained the same, with its elegant proportions hard to better, further refinement has been produced by improved internal cabinet bracing, internal profiling and constrained-layer damping. They continue to be a 3.5 way system with a dedicated midrange unit.
Most importantly improved drivers have become available as materials technology has progressed, leading to improved cone break-up and lower distortion of their sound output. At the heart of the new Kantus is the superb 100mm midrange unit made from high strength aluminium alloy coated on each side with very hard ceramic so that it remains pistonic well above its crossover point. This results in extraordinarily low distortion through the critical midband region allowing these vital frequencies to come through crystal clear and without the hardness or muddle of many loudspeakers in this region.
Another feature is its excellent tweeter made of beryllium (Be) metal, one of the lightest and strongest materials but also very expensive – half a tonne of it is used in the recently launched Webb telescope because of its lightness and strength but its total cost was over $10 bn! The clarity of the tweeter means that fine details of the performers’ art are revealed but because the ultimate breakup frequency is above 40 kHz there is also a natural ease about its sound.
The Kantus continue to use a low-distortion bass unit made from very strong aluminium alloy with radial ribs to increase its strength even further to ensure ‘break-up’ occurs well outside the frequency range over which the driver is used. Together with excellent motor and suspension systems, the ensuing low distortion allows the listener to hear tonal structure in bass notes, again resulting in greater realism of the reproduced music – and not just some homogenised version.
The revealing clarity of these drivers is maintained by their high-quality crossover filter components. With the Kantu Be we have used very high quality (and expensive) polypropylene capacitors in series with the very high quality (and expensive) Be tweeter plus high quality polypropylene capacitors in the midrange and bass Xover filters.
Likewise the inductors have been chosen to meet the requirements of the particular driver – though they are all air cored so have none-of the hysteresis distortion of iron or ferrite cored ones (due to their atomic magnets getting ‘stuck’). With the inductors that are in series with the bass units that need large currents we have used some flat-wire copper inductors that I had in stock and have the same very low resistance as 3 mm round wire. The midrange and tweeter inductors are much smaller and pass less current so use 1 mm wire.
Finally we use only high wattage (so they don’t change resistance with temperature) resistors that are non-inductively wound to prevent any high frequency loss. All components are soldered directly to each other to reduce path lengths and soldered to the input connectors and drivers using very high quality cable.
As shown by the attached measurements, because the new Kantus are so accurate with such flat frequency response and low distortion they are very faithful (high ‘fidelity’) and truthful to the music and equipment preceding them in the reproduction chain so will take on the latter’s sound character. If you prefer your music ‘warm or sweet’ then you must partner them with a suitably ‘warm or sweet’ amplifier – perhaps a valve amplifier. Or if you enjoy your music fast & dynamic then choose a suitable fast & dynamic solid-state amplifier. But given the right preceding equipment you will hear all the emotional drama and nuances of the artists’ playing. Like being there!
A leading recording engineer wrote of the Kantu 9s: “The overall clarity of these is exceptional – particularly the upper mid-band as one of the critical factors I seek is natural voice reproduction – without excessive sibilance or ‘chestiness.” The new tweeter and midrange units of the Kantu Be add further clarity plus ease and naturalness to this reproduction.