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The company's two flagship models incorporate an AMT which in Elac speak is a JET; plus a built-in 4pi Plus.2 super tweeter on top. It's the Germanic take on the same recipe which the Mythology M1 pursues by marrying an already very capable main tweeter with a dedicated super tweeter.

Other well-known purveyors of discrete super tweeters include Tannoy and Townshend. Similarly to how a sub can connect speaker level via a 'biwire' cable where one half connects to the mains, the other to the subwoofer, so super tweeters are fed the same signal as the mains (usually by jumpering directly off the speaker terminals for a shorter run but possibly also by doubling up on the amp's outputs). You thus have another cable hanging off your speakers. That could become a minor eye sore at least from the side. But as all women in pointy high heels would tell us, beauty comes at a price. No pain, no gain.


On actual wallet cramps, here it means €2'098/pr. That's serious money for what might seem but a tweak and nothing you'd throw at a pair of $1'500 mini monitors. In fact the inherent see-saw principle of building out the frequency extremes nearly demands that your main speakers be bass complete. In most reasonable cases that should mean an actual infrasonic subwoofer rather than attempting this feat with a passive tower. The sub-ject for music of course is quite taboo. Most close-minded audiophiles associate subwoofers with nothing but T-Rex foot falls, submarine rocket launches and other Hollywood excesses. It's the super tweeter which remains well beyond adolescent pursuits. Super tweeters don't make your pants flap. They don't dislocate pictures from the wall. They don't annoy your neighbours. In fact with adolescent music replayed as compressed MP3 over inferior hardware, they make for very poor and ineffective demonstrators indeed.


Super tweeters are for connoisseurs. They must trust their own ears since there is no truly compelling scientific argument to rationalize the device. Perhaps that's why compared to subwoofers, super tweeters are so rare. It's nearly impossible to argue their merit successfully without having first-hand experience. Even then many you'll talk to will merely grant you a blank stare or commence a litany of arguments to prove your folly. For another commercial realization of a ribbon-based omni tweeter by the way, there is the rarely seen Raal Requiste by Aleksandar Radisavljevic of Raal Ribbon. My photo shows the prototype's circular ribbon array.

To complete introductions, Elac the company goes back to 1926 as Electroacoustic GmbH. After WWII, a Siemens contract for a radio set put Elac on the audio track. By 1948 they had their first record player with changer automatic. Production of loudspeakers began in 1984 and the first iteration of the 4pi omni tweeter occurred a year later. By 1998 Elac had its own in-house magnet manufacture. 2 years later they began to produce their JET tweeters with SCARA robots. 2003 saw the JET in its 3rd iteration. 2005 launched the dual-concentric X-JET. In 2008 they began to supply the automotive market with OEM drivers.


All throughout, the base of operations was always Kiel where I grew up and went to school. It's a harbour town on Germany's East coast. It not only serves as a very busy ferry terminal to Scandinavia but also hosts the annual Kieler Woche. That's a world-famous sailing regatta in the Baltic Sea that's grown into one of the globe's biggest events of its kind.


For final tech inquiries, Yvonne Meinhardt connected me with Rolf Janke. I wanted to know whether the 4pi Plus.2 was a circular AMT derivative or actual ribbon (their drawing suggested the latter); whether its sensitivity adjustments were basic voltage dividers or a multi-tapped transformer; and how steep or shallow the hi-pass filter slopes were. Obviously adding a parallel nominal 6Ω load increases amplifier demands even if tweeter bandwidth isn't current hungry. Still, your amp should be stable into 4Ω even if your speakers are of the 8Ω type. Depending on adjustment, the 4pi Plus.2 can present a minimum 3.5Ω load.

For wiring up the 4pi, Elac don't recommend anything above 2 x 1.5mm² for up to 4-meter runs unless the main speakers are low-impedance types. That might warrant 2 x 4mm² conductors for the super tweeter. Obviously one shuns highly resistive cabling due to its counterproductive HF roll-off. The 4pi diaphragm is a 5µm aluminium foil embossed with a wave pattern driven from a custom transformer to guarantee 53'000Hz bandwidth. Because this transformer's quality and stability are critical, the efficiency adjustments are made with resistors, not secondary windings. The filter slope is a 2nd order function both acoustical and electrical. At the maximally 1cm wavelengths involved, Rolf Janke opinined that phase wasn't that interesting. The high-pass frequency is adjusted with capacitor changes. The enclosure and wave guides are diecast aluminium. Rolf was quick to stress the vital importance of their non-lossy switches which must operate with very low voltages. "These switches are silly expensive" he laughed on the phone, "but essential to the peformance."

Finally and as you may have figured out already, the 4pi Plus.2's circular dispersion implies that it will at the very least restore full-space HF radiation to correct in-room power response for the treble which always falls off seriously above 7kHz. That's true even if its 3'500 to 53'000Hz coverage won't add actual bandwidth beyond an advanced main tweeter (Elac's own JET makes 50kHz). That's where the Elac goes beyond competing super tweeters to propose that its primary benefit isn't bandwidth at all. It's its unique 4pi dispersion. It's precisely why this Elac had my attention over a revisit with the monopole planar Sopranino. Gallo's 180° CDTIII tweeter does wonders for soundstaging. Didn't it stand to reason that the 360° 4pi Plus.2 might graft a satisfying echo thereof—or even more than an echo—onto normal speakers?