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In the hubbub that is the sensory overload of Munich HighEnd 2012, one interesting contribution to the loudspeaker art found itself barely talked about in any of the follow-up show reports and blog chatter. I'm thinking of Dome Phase's unique 180mm dome-shaped dual-concentric driver demonstrated in their Posion I and II monitor and floorstanding models. Consider Amphion's Ion+ at left. Its tweeter loads into a waveguide of the same diameter as the matching 4.5" mid/woofer. Such acoustic impedance matching symmetrizes the radiation patterns of two drivers at their crossover point. KEF's LS50 at right relocates the tweeter into the center of its mid/woofer, thus rendering the latter's membrane an effective HF waveguide. It overlays Ion's two-driver concept on a single axis.

Chinese company Microlab and their brand Dome Phase cite German, European and Japanese patents—China and US applied for—to protect their coaxial driver geometry which inverts what Tannoy, KEF, Thiel & Co. have championed for decades already. To give their embedded 28mm tweeter a field of radiation unencumbered by a constantly moving surrounding, they've placed it at the apex of what appears to be a steeply domed mid/bass driver.

Their obvious contention is that a tweeter freed from the acoustic horn loading of traditional dual-concentrics performs better.

On paper it's a quite compelling argument. Whether in practice structural weaknesses in the mid/woofer's geometry counter it remains to be seen. ATC has long employed their 75mm dome midrange very successfully. Swans has an equivalent transducer. To my knowledge however nobody has attempted a bigger dome driver. Until now? Have very specific engineering challenges held back the usual driver makers? Was it the exposed nature of the concept that seemed unattractive for potential damage in domestic or professional applications? As the above photo shows, the Dome Phase driver rather does protrude to impact cosmetics and create a bump-in obstacle just walking by.

As the photos at left show without the grille, even this tweeter remains set into what appears to be a stiff stationary umbrella from behind which the loaded mid/woofer radiation is dispersed to the sides in quasi omni fashion. In fact it nearly looks as though the mid/woofer actually faces backward, having its spider towards the tweeter umbrella to be no dome at all, just a cone driver viewed from behind. Which would make the umbrella a shield for its magnet perhaps? Regardless, the Dome Phase driver seems different to create many questions and a general curiosity. I look forward to learning—in these pages or elsewhere—whether it really bestows demonstrable advantages over the usual twin-cone drivers we're already familiar with ...

At this juncture reader Robert Gaboury rattled my fence. You may remember reviewing Artistic Audio's Möbius back in 2004? (I'd completely forgotten; see below.) As far as I know the patent belongs to Reckhorn...

Dome Phase does indeed reference the Reckhorn patent

...whilst the inverted chassis design has been made popular by Volt and  is used by PMC in their big monitors. Putting a tweeter at the top of the frame was a formality accomplished in the coaxial radial Volt RCXD3153 PA driver."

Cough. There you go then with our Editorial Oversight Commission in full swing. But it leaves a new brand with potentially promising product to investigate even if the driver technology is pre-existing and merely licensed...
Dome Phase website