There aren’t very many loudspeaker companies that do in-depth research and build their own drive units in this business. DALI is a rare exception, and one that has been making some impressive technological breakthroughs in recent times. The Epicon series is DALI’s flagship range, comprising two floorstanders, a bookshelf, and a centre channel for home cinema systems. They have fabulous finishes, distinctive woodpulp cones with a maroon colouring, and all but the bookshelf has a ribbon tweeter.
The Epicon 8 is the daddy. It’s a ‘three and a half and a half way’, in that it’s a conventional three-and-a-half way loudspeaker with the ribbon tweeter counting as an extra half way in its own right. The suffix 8 springs from its use of eight inch (200mm) bass drivers that, alongside the 165mm midrange, benefit from DALI’s analysis of loudspeaker magnet systems. This research identified that eddy currents induced in a conductor by variations in the magnetic field cause breaks in power to the motor system. DALI’s engineers found that they could reduce the effect of these eddy currents by using pulverised rather than solid iron ferrite for the edge of the gap where the voice coil sits, where its lower electrical conductivity is most beneficial.
This soft magnetic compound (SMC) also displays lower lag time between magnetisation, induced by the voice coil, and demagnetisation. It doesn’t make for a more efficient drive unit in sensitivity terms, but does produce less heat and results in lower distortion. SMC was originally developed for diesel rail injectors, but being first out of the gate, DALI has patented the technology’s use in the hi-fi universe.
The drivers themselves are made from doped wood pulp which is essentially a slightly coarser version of paper, it was selected because the lower uniformity of the material avoids high Q resonances. These are bonded to soft rubber surrounds with carefully selected glues, the softer rubber chosen because it delivers better low level sound quality. This does not, I’m told, make for lower longevity as has been the case with softer surrounds in the past.
High frequencies are produced by a 29mm soft dome that hands over to a ribbon tweeter at 15kHz, making the latter effectively a supertweeter. The ribbon is specified to 30kHz, but has a relatively low output and good horizontal dispersion. This may be why DALI recommends that its speakers be positioned without toe-in.
DALI does not make any special claims about the Epicon 8 cabinet save that it’s constructed from a laminate of MDF sheets. These allow its sides to be sculpted into an inherently stiff curved shape, and the multiple layers of glue give it a degree of a self damping. DALI does mention that there are ten layers of lacquer, which produces a finish that’s remarkable even by the high standard of speakers at this price.