Danish manufacturer Raidho demonstrates diminutive hand-made D-1 stand-mount speakers at Australian AV and Audio Show 2014.
The D-1 is a unique speaker, because both its sealed ribbon tweeter and its 115mm diameter bass/midrange driver (with a diamond-coated cone) are made by hand in Northern Denmark. On hand to demonstrate the speakers to showgoers was one of the co-owners of Raidho, Frits Dalmose. ‘Raidho’s one of a kind sealed ribbon tweeter has an ultrathin membrane weighing less than 0.02grams that is driven by extremely powerful neodymium magnets,’ he told Australian Hi-Fi magazine. ‘Due to the low mass, the tweeter stores no energy, has no resonances, and as a result leaves no sonic footprint on the music.
The Raido D-1’s bass/midrange driver is, like the tweeter, hand-made in Denmark. The 115mm cone is made from aluminium which is first chemically treated so that its surface oxidises into an ultra-hard ceramic material. The cone is then bombarded with carbon particles that are fired at it at such high speeds that some of the carbon is transformed into diamond, ultimately building up a 10 micron -thick diamond layer over the ceramic surface. This further stiffens the cone material, which has the effect of moving its fundamental resonance frequency above 20kHz, high enough that the D-1’s crossover will damp it by more than 36dB. As for the magnets, Raidho uses multiple small neodymium magnets arrayed in two separate ‘rings’ around a copper voice coil mounted on a titanium voice-coil former. ‘We use titanium so there’s no hysteresis in the voice coil gap’ said Dalmose. ‘Because of the strength of the magnetic field, we can also have a much larger than usual magnetic gap, which completely eliminates air compression.’ Dalmose said that both drivers were entirely the work of Raidho’s designer, Michael Borresen, who Dalmose claimed was a genius. ‘Michael’s brain is really strange,’ he said. ‘He seems to know so much about everything. He’s not only a genius at speaker design: he’s also designed running shoes for Nike, fishing rods, and gun housings for the Eurocopter. He’s so fanatical about his designs that he wouldn’t let us use even the most expensive state-of-the-art capacitors in the Raidho crossover… he insisted we had to make them ourselves, because he said we could do better.’ The crossover is also unique, because rather than looking at voltages, Raidho says it wants the current through the high-pass section of the crossover to be the same as the current through the low-pass section. ‘This locks the two drivers together in a truly unique manner,’ said Dalmose.
Raidho loudspeakers are distributed in Australia by Entertaining Environments, which has recently introduced what it calls an EE price guarantee. ‘What we do is guarantee that Australians will pay no more to own a pair of Raidho speakers than anyone else in the world,’ said Rob Sanders, of Entertaining Environments. ‘And everyone who hears them will want to own a pair, because every one of their models is astounding. The speed of the drivers is awe-inspiringly fast, and every time I listen, I continue to be amazed. They also partner spectacularly well with Moon Audio’s amplifiers, which we also import and distribute in Australia, and which are also covered by the EE price guarantee.’
Pictured Below: Frits Dalmose showing the unique hand-made bass/midrange driver that's used in the Raidho D-1
For more information, contact Entertaining Environments