This idea was in fact developed by Grundfos for high-speed electric motors, not for speaker drivers at all. But, fortuitously, Grundfos is close to DALI in Jutland in Denmark, about ten miles away, and after a while the subject of using the idea for speaker magnetic structures came up (the idea was actually suggested by Grundfos, according to Worre in the video link). Of course, some work was needed on how to carry this out, but the idea has a fundamental rightness to it that strikes one immediately. Like many really good ideas, once this one has been brought up, it seems entirely natural.
And what can one say but that DALI and Grundfos have made it work? In measured terms, the odd-order harmonic distortion, which has been widely observed to be the kind that sounds bad, is all but gone. People tend to think of distortion in speakers as arising from break-up of the driver cone, and a lot of work has been done on making cones so as to minimize distortion of this sort. DALI has addressed that here as well, with special wood-fiber driver cones, which seem to work admirably. But the distortion from the motor mechanism also counts, and here in the Epicon Series, this problem is addressed in a new way, as noted. And it does the job in listening terms as well as in distortion measurements. (The new structure is also said to minimize problems from magnetic hysteresis effects.)
The sonic effect is, as mentioned, immediately observable and extremely pleasing. Or at least one supposes that it is this one is hearing; that the speaker sounds unusually pure and liquid is definitely the case. The attribution to the new magnetic approach is less obvious, but I am prepared to take DALI’s word for it that that is the cause of the unique sound heard. And the measurements surely back DALI up.
The Sound Overall: The Frequency Extremes
So take it for granted—not that you will have any trouble noticing!—that the Epicon 6 has an unusually low level of perceived distortion, a kind of meltingly liquid sound that one does not expect to hear this side of Quads. There are, of course, other aspects of the sound to be discussed, though the perceived low distortion of the speaker already makes it of compelling interest.
Let me start with the frequency extremes. The DALI has an unusual high-frequency driver, comprising a dome tweeter that is rather larger than usual (29mm) surmounted by a ribbon tweeter to fill in the top of the top octave—and actually a long way beyond (ribbon drivers tend to go way on out there). The result is a very high level of perceived high-frequency clarity—you will hear a lot of the micro-detail so beloved of audiophiles, helped on by the ultra-low distortion all the way down, as already noted.
This speaker has resolution and clarity in spades. The idea of using two tweeters to cover different parts of the treble is not new—it goes back at least as far as the Spendor BC1. But it is surely carried out to good effect here as far as apparent clarity and resolution are concerned. Things like the high percussion in one of my go-to orchestral recordings, Rachmaninoff’s Symphonic Dances (Mata, Dallas, ProArte) sounded remarkably like real cymbal crashes, with the requisite micro-structure that is really there in reality and on the recording, but that can turn into an undifferentiated blur with less than stellar tweeters. In these terms, the high-frequency compound unit of the Epicon 6s is in the top echelon, one of the best. If the high end is anything like synonymous with high end for you, you will be very happy here as far as the intrinsic behavior of the unit is concerned.