Dramatic Danish invention called ‘Dali Drive’ used in revolutionary Dali Epicon 6
The bass drivers in Dali’s new Epicon 6 loudspeakers, which made their first appearance at the 2012 CES in Las Vegas, use an innovative magnetic drive system developed by Dali, which is manufacturing them 100% ‘in-house’ in its factory in Denmark: the first time in Dali’s nearly 30-year history it’s ever done this. The driver magnet uses soft magnetic compounds (SMC) that the company says eliminate variations in the flux strength in the magnetic gap and ensure linear magnetic properties throughout the frequency range. The SMC starts out as iron powder, but then goes through three different treatments to transform the powder’s physical properties, so that by the end of the process, the material is not only solid, but also completely electrically non-conductive, unlike normal iron loudspeaker magnets. ‘We’re not the first loudspeaker company to try to build a non-conductive magnetic material,’ said Dali’s Director of Innovation, Kim Kristiansen, (pictured right holding driver and magnet) who should know, since he formerly worked for two of Denmark’s most famous driver manufacturers, Vifa and ScanSpeak. ‘I don’t know if I’m proud of the fact that it’s taken us three years to get this new driver to market, but it has,’ he told Australian Hi-Fi Magazine. Kristiansen said other manufacturers tried to make their magnets non-conductive using a process known as sintering. ‘Sintering reduces conductivity by a factor of ten,’ he said, ‘whereas our process is one thousand times better again.’ Kristiansen said that the performance of the bass drivers in the new Epicon 6 was also improved by a new version of the cone material Dali has been using for some time, and also by wrapping the pole piece in aluminium. Together, all these developments have reduced the driver’s total harmonic distortion (THD) by a factor of ten compared to an identical driver not using these materials. ‘When building a loudspeaker, it’s important to always maintain a balance of ingredients,’ he said. ‘I like to use the analogy of making a chocolate cake. When making such a cake it’s essential to use the right amount of chocolate. Too little chocolate in the mix and it’s just a cake, but if you add too much, it’s no longer a cake at all. So even though the SMC is important in the design, it’s not solely that which makes the speakers sound so good.’
And they did indeed sound very good indeed in Dali’s demo room in the Venetian Hotel, listening to Madeleine Peyroux singing Dance Me to the End of Love.’ A part of this is because of the aspects of the driver’s design that make it easy for an amplifier to drive. Such as the fact that the voice-coil inductance is reduced from a typical figure of around 1.7mH down to just 0.55mH and that this low inductance remains constant right throughout the full range of driver excursion, which means that there’s the optimum conversion of amplifier voltage to current flowing through the voice-coil.
With so many advantages from the new design, we just had to ask Kristiansen if there were any disadvantages, such as an awkward resonance frequency, perturbations in the frequency response or reduced efficiency. On hearing the question, he smiled ruefully. ‘No, none of those things… the only disadvantage is the price.’ That said, you can purchase a pair of Dali Epicon 6 loudspeakers for $US13,500 in piano black, or $US14,000 (your choice of real wood veneer.) The Epicon 6 uses dual bass drivers which cross to a hybrid tweeter (a combination of a ribbon and a soft dome).
Manufacturer’s Specifications: Dali Epicon 6
Frequency Range: 35Hz – 30kHz
Crossover Freq: 700Hz/2.55kHz/15kHz
Nominal Impedance: 5-ohms
HF Drivers: 29mm soft dome, 10x55mm ribbon
LF Drivers: 2 x 6 ½”
Enclosure Type: Bass Reflex
Dimensions (HWD): 40.4” x 9.2” x 17.4”
For more information, contact Dali Distribution.
Above: Manufacturer's graph showing reduction in THD using Dali Linear Force Motor System. Red trace at top is driver without any of Dali's new technologies. The other three traces show the improvements as each of the technologies is added, with the final result being the green trace at the bottom of the graph.