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Conclusion. Does it mean that the D-1 is flawless and can safely replace any floorstander provided you gave up on a narrow range of the very lowest frequencies? Not really. One needs to favor a closely shown palpable warm foreground and dense sound. This is how the Danish speakers emphasize coherence. They also tend to focus the listener's attention on what is happening just in front. Decays, reverb and details located deep in the back of the soundstage are very natural and distinct but covered by what’s in front of them to perhaps seem fainter and less clear. One also needs to know that true low bass won't exist. The extension on Dominic Miller’s Fourth Wall and the 24-bit version of Depeche Mode’s Delta Machine was impressive because it was part of something bigger and never for its own sake. But the lowest end also apparent with the double bass was only hinted at and not really reproduced. The overall density of sound was thus lower than with the Harbeth though not by much and we may never notice it due to a close-up presentation where the impression of bass becomes the exactly opposite.

These however are only minor things against which we get a whole lot of goodness including excellent resolution, coherence, fluidity, dynamics, warmth, softness and imaging. While I still think that the Dynaudio tweeter of the old Sonus faber Electa Amator has even more resolution and delicacy, the difference is not large by any means. From now on Raidho's quasi ribbon secures second place in my personal tweeter pantheon. The D-1 is huge money but the sound is equally big as is the pleasure of listening to music with these boxes. This is bona fide engineering with high development/parts costs and great performance.

Design. Two-way speakers almost always look the same - small rectangular boxes with two drivers mounted to the front baffle. In most cases the cabinet is made of MDF, sometimes fiber board, sometimes multi-layered hardboard or plywood. Very few are made of solid wood. Their fundamental shape was modified by Franco Serblin in first his Sonus faber and then Accordo speakers where the cabinet sides curved back into the cross section of a lute. Speakers of this type have a wide front baffle and a narrow spine. The D-1 follows that archetype but also the latest Magico and Sonus faber speakers with their stiff metal front and rear baffles. Here the front is actually made of two slanted portions, the vertical upper half for the quasi ribbon tweeter and the lower up-angled one for the 115mm mid/woofer. The sides, top and bottom are wood-veneered MDF.

Both drivers are in-house Raidho issue which makes them stand out from speaker manufacturers buying off the rack. The quasi ribbon tweeter sports a 0.02g aluminum membrane and powerful neodymium magnet. Neodymium magnets are also used in the pistonic mid/woofer where they are arranged vertically in a push-pull configuration around a dual voice coil. This creates an open structure for unhindered air flow. It's a very expensive design with a highly durable basket. As in the C-1 the cone is made of a tri-layer sandwich of aluminium core with sintered ceramic skin which then get an additional coating of thin diamond to give the cone even greater stiffness. The back panel features a single pair of terminals and a bass-reflex port. Internal wiring is made of the most expensive Nordost Odin Supreme Reference. Lars Kristensen’s Nordost connection clearly paid off. It is extremely rare for a speaker manufacturer to use such expensive premium cables in their designs. Off the top of my head I can only think of Crystal Cable doing it too.

The cabinet is not only reinforced with aluminium plates on the outside but heavily braced inside with a vertical window-pane MDF frame. There is no damping material in the front but the space behind the dividing brace is tightly packed with natural wool. The same damping is used in a small tweeter chamber. All internal surfaces look as if they were impregnated with a wax-like material. I didn’t manage to see the crossover network apart from a large ribbon coil silicon-mounted into a frame opening. Removing the back panel showed that the designer didn’t neglect the reflex port. Where even Harbeth use paper tubes with plastic flares, Wilson Audio goes metal as do do Raidho – their exit flare is aluminium and the port tube some kind of plastic, probably polyethylene. The level of workmanship and finish quality is exceptional as is the quality of all the components which must cost a fortune. Nothing was left to chance. Apart from that it’s a classical two-way stand-mount rear-ported monitor.

Specifications according to the manufacturer:
Type: stand-mount speakers
Frequency response: 50Hz - 50kHz
Impedance: >6Ω
Crossover frequency: 3kHz/2nd order
Cabinet: rear-vented
Drivers:1 x quasi ribbon tweeter, 1 x diamond coated sintered ceramic/aluminium sandwich 115 mm mid/woofer
Finish: Black piano lacquer plus all available veneers and lacquer colors
Dimensions: 200 x 370 x 360mm
Weight: 12.5kg/piece
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