During our Munich chat, Grzegorz was open to loaning me either model in his current roster which won't expand anytime soon. There's Gemini at €23'499/pr, Libra at €8'499/pr and matched stands at €1'399/pr. Non-standard finishes like gold, silver, patina, rust and more charge extra and are first discussed with the designer. He's open to other ideas as long as the tech at his disposal allows for their execution. I opted for Libra primarily due to its compact footprint and already ace street cred. When convenience talks, I listen. The loaner set came from Maciej Lenar of AudioPhonique. Each speaker inside its own cardboard box nested in precisely cut foam cradles to support the asymmetrical shape. Powder-coated white steel stands had their flat bits secured by circular foam because I had no space to store two more large boxes.
As far as tech details go, Gemstone's site and Grzegorz are quite tight-lipped. We know that each speaker measures 45 x 37 x 22cm DxHxW and weighs 8kg so is unusually deep yet perfectly manageable by one adult. Libra's declared sensitivity is 86dB and it's obviously a rear-ported 3-way. Nominal impedance and bandwidth are given as acceptable and sufficient. Though I was told exact numbers which seemed honest and was also briefed on parts choices to better understand the product, none of it is meant for public consumption. Grzegorz wants listeners to evaluate his speakers based on their actual performance not parts and specs. However, Grzegorz was quite open about his enclosure, arguably the most intriguing part of this design. Concrete cabinets aren't new per se. We've already seen quite a few over the years. The density and weight of concrete make it a material with great mechanical properties of resonance absorption and mass damping. Concrete tends to be very heavy but Libra isn't. That's because it exploits a novel mineral compound that's mechanically inert and light. Prior to learning about it, Grzegorz had sampled dozens of similar materials. That alone took several years, multiple trial 'n' error experiments and significant financial investments. We don't know what exactly constitutes the man's final chemistry but specialist concrete powder and resin are two ingredients on a far longer list. The manufacturing stage involves casting as one step of many whose timing is critical. Past the initial cast, the compound needs 30 days in specific environments to become chemically stable and ready for post processing. Libra's front panel uses a different compound which increases manufacturing complexity. The enclosure's variable wall thickness spans from 10 to 15mm.
I'm not entirely sure whether today's photos communicate it but Libra in the actual stone is one gorgeous looker. The concrete texture with its uneven cracks and crevices feels very nice to the touch. It's just personal preference but I'd take this finish over veneers, lacquers and most woods in a heartbeat. Libra's elegantly raw exterior makes it very much a premium design that was neither cheap nor easy to make. This racy enclosure tilted on the rear uses multiple angled planes to minimize internal standing waves. Since the faceted result resembles a gem, the brand name seems fitting. As far as fit 'n' finish go, Libra is excellent. All edges are finished nicely, tolerances are tight. I applaud Grzegorz for expertly incorporating WBT speaker posts and drivers in his composite cabinets. Although the identity of Libra's drivers remains a secret, we see that it's a three-way affair. There's a cellulose mid/woofer, aluminium dome tweeter and ribbon super tweeter. I can't say much but the ribbon is actually more than a super tweeter and the interaction between mid/woofer and dome tweeter unusual as well. The filter network occupies a large PCB which keeps all aircore foil coils as far from one another as possible. Crossover parts are from Mundorf and Jensen, hookup wiring is from Neotech. Two cross braces reinforce the cabinet and support the filter board. The asymmetrical driver alignment can set up the dome tweeter in or out where Grzegorz suggests in but experiments are welcome.
It was crystal clear that Libra would have to battle my resident monitor above, the Swiss sound|kas Vox 3awf. Both are in a roughly similar financial ballpark. My Trilogy 995R monos pack enough power to accommodate both loads with their noticeably different sensitivities where Libra is the far harder nut to crack. In my room it also behaved like a conventional rear-ported design. Move it too close to the front wall and bass overloads. Limit boundary gain too much and bass leaves the building. Determining my best balance was hardly a chore but allowable wiggle room just ~30cm. One meter from the wall still had the bass way out of proportion, bloated, boomy and slow. Half a metre more and it got too lean for my taste. 130cm was the golden ticket. Now Libra's lows showed muscle, reach and substance and kept smear and unwanted turbulence at bay. Room talk didn't factor either. This was good for a rear-ported design relatively close to my brick wall. A gentle toe-in with the dome tweeters facing inward sealed the deal. It's worth noting that the Vox stands are significantly shorter so I wondered whether this was about to become an issue. It didn't. The naturally tilted Swiss speaker set radiates at an up angle and aims exactly at my head. The newcomer on its own tall a good meter closer to the front wall had the extra distance secure imaging that felt coherent and not overly elevated. The comparison of the two monitors on their stock stands was a go.