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This review first appeared in the July 2009 issue of hifi & stereo magazine You can also read this review of the Hornmanufaktur Allegro in its original German version. We translated it through a syndication arrangement with our German colleagues. As is customary for our own reviews, the writer's signature at review's end shows an e-mail address should you have questions or wish to send feedback. All images contained in this review are the property of or Hornmanufaktur. - Ed.

Reviewer: Ralph Werner
Sources: Analog - deck - Acoustic Solid MPX; tone arm - Phonotools Vivid-Two, SME M2 12-inch; carts Denon DL-103, Ortofon MC Rondo Bronce, Shelter 201, Zu Audio DL-103; digital - CD player - HIFIAkademie cdPlayer; Computer & Co - Logitech Squeezebox, Readynas Duo NAS-Server, HP Notebook; D/A converter - Aqvox USB2DA-MKII, Benchmark DAC1 USB
Amplification: Phono - Aqvox 2 CI MKII; preamplifier - Octave HP 300 MK2; power amp - Electrocompaniet AW180 monos; integrated - KingRex T20, LUA 4040C, Myryad MXI 2080, Rega Elicit
Loudspeaker: Thiel SCS4, Zu Audio Druid mk4
Racks & Stands: Creactiv, Taoc, Liedtke Metalldesign Stand, Shale Audio Base
... and various cables
Review component retail: €5,000/pr in Birch veneer

"For many years, Hornmanufaktur has built loudspeakers which don't conform to the usual hifi norms and fashion statements but to the frequency response of the human ear." That's how the firm whose bestselling Allegro model is today's focus puts it somewhere on their website. Without any fancy footwork on interpreting that statement, two consequences seem obvious. There's solid self-confidence at work to oppose the speaker mainstream (however you'd define that mainstream); and this maker relies more on trust in his own ears than measurement fetishism. Hence the slogan "Qui habet aures audiendi audiat". A biblical quote (Matthew 11,15) for an advert's punch line? This promised to get interesting.

The man behind Hornmanufaktur is Gerald Hüpfel, chef and developer of some pretty special speakers from Austria. His self confidence is echoed in his bio. An IT manager who enters the highly competitive loudspeaker arena better have gumption and specific skills. Hüpfel is quite the interdisciplinarian too. After completing electro technical and sound engineering studies to combine science and art, he studied musicology to focus on music theory and history. "This comprehensive background was a prerequisite to attack the design of musical playback equipment" puns Hüpfel who followed high-school with an engagement at conducting opera in Vienna..

Five years ago, he commenced horn manufacture less than 80km outside of Graz in the Southern Burgenland - back-loaded horns like today's Allegro. This type of design amplifies the lowest two octaves by funneling a woofer's rear wave through a horn. The Allegro is defined both by its rear horn and the use of a singular widebander. It's a 1-way, without crossover. The visually most distinctive element of this drive unit is its light beige color. It stems from a cellulose that's harvested from the Banaba plant, also a healing herb whose exceedingly long fibers are said to make for very stiff yet light membranes. To enhance their self-damping properties, the cones are liberally oiled which closes off the micro fibers' molecular pores. Afterwards natural lacquers increase overall stiffness but also lock in the oil to prevent migration. A close inspection confirms a "fibrous and oily" appearance..

As is quite common for the breed, this transducer combines two membranes. A 16.5cm diameter cone extends to ca. 12.500Hz whence the smaller 7cm whizzer cone takes over to improve treble with less beaming. With the Allegro, this whizzer attaches directly to the voice coil whereas the main cone couples to the whizzer via a damped bridge. At ca. 12.5kHz, this mechanical low-pass activates at about 12dB/octave and Hornmanufaktur refers to their solution as a "quasi coaxial transducer sans electrical filter". This mechanical high pass mirrors the back-loaded horn which loads the widebander in the lower octaves such as to seriously damp down excursions compared to 'normal' boxes. That reduces the front-firing output and is strategically countermanded by the 'virtual bass membrane' of the horn mouth which is driven by the cone's backside. Horn action covers about 40 to 120Hz while the separation between direct radiation and horn augmentation enters with a 24dB/octave angle.

To respond to a Physic drop-out's "whutza horn" quip, let's start basic and with radiation resistance. This determines a moving membrane's ratio of electrical to acoustical conversion in both sound pressure (gain) and air movement (loss). Conventional speakers suffer the latter particularly in the bass where losses exceed gain. Put differently, they move more hot air than create bass pressure. Naturally, frequency affects this ratio. The lower a tone, the more time the air has to evade the cone's excursion by escaping sideways rather than finding itself compressed. At higher frequencies, this reaction interval shrinks and both radiation resistance and acoustic gain increase.