Reviewer: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 12.2), PureMusic 3.02, Qobuz Hifi, Tidal Hifi, Fore Audio DAISY1, COS Engineering D1, Aqua Hifi La Scala MkII, Fore Audio DAISy1, Metrum Hex, AURALiC Vega,
Preamplifier: Nagra Jazz, Esoteric C-03, Vinnie Rossi LIO (AVC module)
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1, F5, F6; Crayon Audio CFA-1.2; Goldmund Job 225; Gato Audio DIA-250; Aura Note Premier; Wyred4Sound mINT; AURALiC Merak [on loan]
Loudspeakers: Albedo Audio Aptica; Sounddeco Sigma 2; EnigmAcoustics Mythology M1; soundkaos Wave 40; Boenicke Audio W5; Zu Audio Submission; German Physiks HRS-120; Eversound Essence
Cables: Complete loom of Zu Event; KingRex uArt, Zu and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Black Cat Cable redlevel Lupo; Arkana Research XLR/RCA and speaker cables [on loan]
Power delivery: Vibex Granada/Alhambra on all components
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Rajasthani hardwood rack for amps
Sundry accessories: Acoustic System resonators, Verictum Silver X block on preamp and amplifier
Room: Rectangular 5.5 x 15m open floor plan with two-storey gabled ceiling, wood-sleeved steel trusses and stone-over-concrete flooring
Review component retail in France: €9'900/pr

Though the only monitor in their 7-deep speaker catalogue,
Apertura place their Kalya third down from the top. They don't position it at or anywhere near the bottom. That explains its sticker to signal ambitions. Those are further illustrated by 35-30'000Hz ±3dB bandwidth with decent 88dB sensitivity as a nominal 8Ω load. This is promised from a 20kg enclosure no bigger than 31.7 x 44.7 x 42cm WxDxH, i.e. with depth its longest dimension. Being down-ported, the 20kg aluminium/wood stand with strategic opening in its top plate is integral.

Apertura at the Munich Highend show 2015, with Lumin and Playback Design.

Where things start taking unique shapes—considering how the 2-way monitor genre is the most populated of all speaker types—is with the physical form factor. To undermine boxiness, only the top and bottom plates are parallel. The outward-curving sides are of dissimilar length and bow to set the narrower back at an angle relative to the broader front. If you orient the speakers with their rear baffles parallel to your front wall, the fronts will be naturally toed in at the listening seat. The tweeters should sit on the inside, with their crescent-shaped foam inserts facing the side walls for reduced reflections.

Deviations from the norm continue with the driver complement. It combines a 2" composite-membrane Fountek ribbon tweeter with an 8-inch isotactic mid/woofer which designer Christian Yvon sources from Seas of Norway, then modifies in-house. This choice of diameter parks the Kalya right between modern where 5.25 to 6.5 inchers are most popular; and vintage/retro where 2-ways were/are built with 10 to 12 inchers. Think Tannoy, DeVore Fidelity and Heco's Direct for the latter. Moving right along, a downfiring port for a monitor isn't exactly common though Wilson Benesch for example do have a number of models doing exactly that. The perhaps most unusual aspect is Yvon's signature compound DRIM filter. It stacks 6dB, 12dB and 24dB/octave slopes on either side of a high 2.8kHz hinge frequency for progressively attenuated steepness. This promises 1st-order phase coherence in the critical overlap window but shrinks the width of it with 7th-order flanks, i.e. far steeper than the norm. I'm aware of only Gauder Akustik with their >50dB/oct. filters doing something similar though I'm not clear on whether their networks are progressive or not.