Our two friends now decided to investigate an in-between solution. Max efficiency would be scrapped as today's users aren't shy on powerful amplification. They also decided to focus on bona fide hifi not pro drivers. The best way to maintain useful sensitivity, in their opinion, would be to horn up their conventional drivers. This should give them the best of both worlds: high dynamics, controlled dispersion but no hard 'compressor' sonics. This led to today's Diva Grandezza. The name arose from the notion that in some ways a hornspeaker is comparable to a famous stage diva: insanely capricious but oh-so glamorous too.  Remembering Maria Callas' extreme behaviour, one had to decide whether to love her or not. This genuine conflict motivated their loudspeaker project. They meant to reach an ideal of diva-esque magnitude. Once other Austrian audiophiles expressed desire to acquire their loudspeaker, our initial DIY initiative acquired an entrepreneurial dimension. Vienna Physix was born. Robert Göschl and Hubert Pfautsch each put a foot into the high-end loudspeaker arena with a very original proposal of their own.


Again, the starting point for their design work was a choice of good dome and cone drivers of sufficient sensitivity and neutrality. Hubert and Robert ended up with a French Audax tweeter and midrange.  Audax are one of the very few hifi suppliers with high-efficiency quality drivers. The chosen tweeter is a TWO24A26, a 25mm silk dome tweeter, the midrange unit a 5" HM130Z10 cone. For bass, Robert and Hubert went after the Visaton TIW 250XS for their top 10-incher that would strike the right balance between woofer/subwoofer applications without needing undue cubic volumes to maintain proper WAF. Their choice was also predicated upon not wanting a typical long-stroke subwoofer driver which would absorb fine detail in trade for extension and shove. With any decision always a compromise, the Visaton appeared to them the best tool for the job which means, being loaded in a vented 48-litre enclosure, with the port and its exit flare solid 1.8kg aluminium.


Having selected their three drivers, it was time to construct, design and measure. Because their day jobs kept them busy, this process took them about four years. The challenge was to come up with an industrial design that would be fit for conventional living rooms and approval by ordinary house wives. Considering the average size of any full-range loudspeaker, design and aesthetics are a definitive issue especially when speakers are really only being used once or twice a week, serving as decorative accessory the rest of the time. I personally cannot contest this consideration. Even the choice of my speakers and acoustic treatment in a dedicated room, used 7 days a week, had to still be approved by my wife. Thus, Vienna Physix said 'no' to a rectangular wooden box that might double as flower pot holder.


Beyond a rather pleasing appearance, the Diva Grandezza is designed from a very ambitious technical perspective. Shapes were drawn to guarantee maximum stiffness in minimal space. That's why the bass enclosure is egg-shaped. It avoids parallel wall and angles to reduce internal standing waves and diffraction issues. Ditto for the midrange's rear housing. The egg shape's constantly diminishing diameter and internal absorptive liners reduce the driver's rear radiation to prevent re-emergence through the horn. One of the most unusual design achievement relates to the horn shapes. Robert Göschl used his own professional IT equipment to draw specific curve profiles that occur between an exponential and tractrix shape. The Shockwave Apparat software originally calculated the shape of a medical shockwave reflector where sound waves transmit focused energy inside the human body to heal several heart diseases. The two designers were able to hijack this program because Robert for years was involved in designing similar devices. Avantgarde's spherical horns by the way differ in using a zero offset at the aperture of their horn mouths. This guarantees that the emitted sound of each horn is not reflected by the adjacent horn but does not allow a positioning of the acoustical driver centers in perfect vertical alignment. Non-perfect vertical alignment usually leads to compromised phase transmissions and a bent frequency response. The latter can to some extent be compensated for by the crossover network if a designer is willing to accept imperfect phase transitions in the filter range.


Vienna Physix believe that vertical alignment solves the timing problem but also risks reflections from the back-set tweeter firing into the rear of the midrange horn. To minimize this, Göschl modified his tweeter's radiation for stronger beaming as a function of crossover frequency and horn geometry. This was optimized after a specialist's modifications to their software arrived at the ideal parameters. Like Avantgarde, Vienna Physix power their bass system to equalize for its sensitivity offset with the horns. This hybrid approach keeps to relatively small proportions for the bass section and thus, good decorator appeal. Amplification is a typical class D ICEPower module from B&O's ASP range, delivering 500 watts into 8Ω. The signal for the amp is taken from the high-level outputs of the main amplifier. Those split into a feed to the passive filter for the hornloaded drivers; and to the internal amp by way of a ground-lifted DC-filtered interface. This protects the main amp during wrong connections and also avoids ground-loop hum. The internal circuit adjusts the low cut, high cut, phase and gain. An external knob controls bass volume from – 3dB to +3dB where flat equals the 12 o'clock position.