Hybrid OB. From a DIYer's archetypal plank of Ply stabilized by L brackets to turnkey versions from Emerald Physic, Diesis, Kyron, sound|kaos, Spatial and Thorens, standard open baffles share a basic concept. They differ mostly in cosmetic detail, baffle shape and whether said baffle is one piece or breaks up into angled facets. Full-range planars by Soundlab and Magnepan too fall into this group. Then there are visually more radical concepts like reflector's four-leafed clover aka the Bespoke from Latvia which Dawid Grzyb reviewed 5 years ago.

In the hybrid open-baffle realm with dynamic drivers not a Martin Logan/Muraudio-style mix of transducer tech, arguably none are as successful as Carl Marchisotto's, first under the Alon by Acarian brand now Nola. His combine classic box bass with dipole mids and tweeters. New Polish company Qualio introduced their own take on his concept at AVS 2022 with the IQ.

For cardioid midrange loading, the Dutch & Dutch 8c which Marja & Henk reviewed shows similar execution to today's Challenger. Its primary deviation is venting its rear emissions out the sides not front so like Amphion. The basic idea is the same: to cause deliberate acoustic short-circuiting for reduced sidewall reflections. Then of course the 8c ('c' for cardioid) diverges massively from today's by going active and using a sealed rear-firing bass array meant to place quite close to the front wall for best effect.

Against these precursors, we can appreciate the Challenger's particular mix of ingredients and execution; including that heavy clam-shell steel frame. We also note that unlike various OB projects by the late Siegfried Linkwitz, today's applies zero DSP to linearize its bass response and delay its 6dB/oct. acoustic roll-off. With this type loading and no DSP, going low tends to depend on exponentially more cone surface. It's why the Challenger's bass array adds up to the membrane area of one 17" woofer per side. Unless stacked and rotated 90° like Lindström's Iso 85 to hide woofers behind a narrower front baffle, going with one big woofer gets ever more broad. It's possible of course but not as likely to lure converts away from classic narrow box speakers. For theirs Silent Pound promise 30Hz reach. And they refer to it as a 3½-way design. The lower woofer operates across narrower bandwidth than the upper one. Dual 6" mids equal the surface of one 8½" driver. There too the Lithuanian packs more.

Here then is the sales proposition for Lithuania's Challenger. It's a compact quite short floorstander of modern styling, 4Ω impedance and standard efficiency. It bolts on controlled directivity across the bandwidth to promise better sound from normal untreated rooms. This I thought demanded closer inspection. Everybody whose space isn't festooned with deflector and absorber panels plus necessarily massive bass traps suffers sub-optimal sonics. It's a global malaise; hifi's own pandemic. To enjoy the benefits of professional room treatments without installing any promised to be a discovery.