With Steve Marsh being 6moons' resident Bastanis man—he owns a pair of Prometheus MkII to double as our go-to guy when US Bastanis dealer Frederic Crane wanted the Wildhorn reviewed—I learnt that "Robert has supplied Andreas with his TOTL AlNiCo widebander which he no longer supplies for his own Bastanis speaker lineup. It used to be in the TOTL Apollo model. A local friend of mine bought it after hearing my Bastanis speakers but Robert has since discontinued it."

At 11.8 inches, the Seligkeit driver called Soul is clearly enormous for a widebander. It's perhaps most closely related to a vintage 12" Tannoy. Where those Scots went dual-concentric to handle the treble bands which remain out of reach to such a woofer-sized midrange, Andreas adds a separate tweeter. That's loaded into a horn which mounts offset. It makes for tweeter-in/tweeter-out setup options. His huge 18" woofer hides behind the vertical front slot and determines overall width of the bass bin. This visually complements the big rising sun disc of the widebander's shallow waveguide.

Whilst cosmetically vaguely suggestive of an Avantgarde Acoustic Duo gone woody and a bit flat on horn depths, a look at the Seligkeit's rear end would quickly kill off any such comparison even if voltage efficiency is surprisingly close. Purely on paper when I accepted the assignment, I related to these cosmetics as being far more attractive than Trenner & Friedl's refrigerator-sized Isis boxes whose sound had so impressed us during the recent HighEnd Suisse show in Zürich. The Isis too had been a vintage-inspired three-way with a hornloaded Titanium compression tweeter, 8-inch paper mid and 15-inch treated paper woofer. At 91dB alas, they simply belong into a different transducer class. And on looks... well, they're unapologetically giant boxes.

Expecting these souls to be heavy customers—the website lacked any indication but common sense could add up all that wood—I would rely on a two-man team from Germany for delivery up our three flights of external stairs before one hits the main door and landing. From there it'd be a furniture dolly and an elevator unless the packaging proved too tall and/or wide for the latter. In that case it'd be another round-and-round staircase up to our top-floor flat. No matter, for once it'd not be my problem. I'd watch others sweat. Yousa!

Relative to our listening space, I'd forwarded Andreas the pictorial feature I'd written on it plus a blueprint just to make sure the Seligkeit wouldn't be too big and I better off with a smaller model. The designer was confident that all would be well. With those items ticked off, it was time for me to go on a fact-gathering mission for more background on the Bastanis/Zugspitz collaboration. Robert Bastani: "The Zugspitz speakers are designed by me but a bit more advanced than my own because l add time-intense treatments which I don't for Bastanis. Thus the Zugspitz drivers are unique and better by a few percent. The Seligkeit does run AlNiCo widebanders but there are 10 years between the Bastanis Apollo and it so the Soul driver is a full step ahead. The same applies to the woofers. The Apollo had a very good 15" sealed woofer, the Seligkeit gets a specially commissioned 18" driver for its H-frame dipole cabs. In short, the Seligkeit is based on exclusive new drive units which are specific to Zugspitz and the best I've yet designed."

As the Jamo R907 and Kyron Kronos show, passive open baffle dipole speakers need very large woofer cone-surface area.
About Bastanis in general: "The central part of any Bastanis speaker design is always a xover-less direct-connected widebander. When a driver sports a proper mechanical roll-off, there is no need for crossover corrections. All crossover parts suffer energy storage effects and even the most exotic costly parts will only adversely affect sound quality. They can never increase the quality of the signal. Some Bastanis designs use big-diameter widebanders. Those produce a very natural midrange without beaming effects. Big-diameter drivers don't need to move a lot to generate even very high SPL so the sound stays relaxed. Transient response is superior and the huge radiating surface offers dynamic headroom far beyond home hifi's requirements. The high efficiency, dynamic headroom and crossoverless direct coupling to the amplifier are responsible for the amount of fine detail even at the lowest listening levels. This makes music come alive and the listening experience reach maximum intensity levels. Bastanis speaker designs use widebanders up to 7kHz or 8kHz depending on the model. Their bandwidth contains nearly all the musical information. They behave as a single point source causing images to be big and natural. Our large-diameter widebanders exhibit bending-wave behaviour at higher frequencies. The cones break up very early and show controlled resonance behaviour across the full bandwidth they work in. Resonances remain far below a disturbing level and the mechanical roll-off to the higher frequencies also is free from disturbing resonances. To achieve this behaviour, we needed new methods of cone treatments to make the paper more elastic. These additional treatments rely on a variety of home-brew lacquers and minerals which dampen and soften different small areas of the cones depending on their behaviour over the pass band.

"At the peak of what's possible" is the Zugspitz slogan reappearing across their website.

"The bigger Bastanis 12" and 15" widebanders are extremely efficient and equal the most efficient hornloaded speakers. Their tweeters need to match in efficiency of course which dictates hornloading. Our Bastanis horn tweeter will easily reach 2.5kHz but since our widebanders well exceed that mark, we cross our tweeters in at about 8kHz. This guarantees freedom from distortion and dynamical compression. Our Bastanis Gemini tweeter works as a horn dipole to eliminate resonances off the back chamber. Its sonic purity and dipole radiation benefit imaging and its high-pass capacitors are made in-house. The hookup wire too is specific to us and even the paralleled resistors for some models are."

For some technical reading on aspects of dipole* speaker performance, Siegfried Linkwitz's website provides quality background from an acknowledged thinker on the subject. His designs incorporate serious DSP correction. Another American designer fond of dipoles is Carl Marchisotto, formerly of Dahlquist and Alon by Acarian, now Nola. As the photos of just a few competitors in this sector show, a common challenge for open baffles is training them for housebroken looks. By design, magnets and baskets aren't enclosed. They're hanging out in plain view. Whilst not visible from the front, it certainly is from the sides and back. This could spell not-in-my-house vetoes. Not having seen any photos of the Seligkeit's backside—even saints have arse holes—I was very curious how Andreas had dealt with that aspect. Purely from the front, I thought the Seligkeit had crossed off the basics of drivers on a raw sheet of Plywood better than any competitor I could think of. But this far into the narrative, I still had no clue as to sell price. Dealing in custom work, the Zugspitz website remains mum on money. I wondered whether it was a case of 'if you have to ask'. Not that it matters when one's main job is sonic commentary.
dAudio's W1

* One obvious aspect is that dipole drivers on an open baffle encounter perfectly—or near-perfect if we discount basket/magnet effects—symmetrical loading. The radiation resistance on both sides of the driver is the same. Here the Seligkeit diverges from the basic concept. For matching reasons, the tweeter is hornloaded; and even the widebander faces a shallow wave guide on just the front. Even so, the principle of not opposing the driver's retraction with higher air compression than it sees on the excursion remains in place. With dipoles, the asymmetrical damping of cones and domes in boxes is much weaker.

This collage on the Zugspitz website shows the relative size of their top model. Given that all tweeters want to be at ear height whilst sitting, the total height of this speaker vis-à-vis a standing man of standard size is no surprise. Despite its bandwidth and dynamic ambitions, the Bliss delivered wouldn't be enormous. On that count it should probably work for most rooms. Dipole radiation of course tends to prefer some distance from the front wall. This delays reflections outside the incident window where the ear/brain automatically sums reflections with direct sound.