By Roy Gregory | May 11, 2019
Raidho Acoustics is a company with a short but undeniably colorful history, its founders combining a talent for self-promotion with driver technology as distinctive as their products’ appearance. In an industry that’s not exactly short on flamboyant characters and overnight success stories (or failures), Raidho still managed to cut a vivid arc across the market in a dramatic — and suitably loud — rise to prominence. But all that bluster was covering some pretty substantial cracks. Impressive technology and striking looks couldn’t hide the fact that many of the models as had crossover-related balance issues that tended to get worse the bigger and more expensive the model, creating an uneven and extremely room-dependent range. If you ever attended one of those early Raidho show demonstrations and wondered why the speakers were placed as far as possible from the walls, now you know.
Throw in reliability and consistency issues that soon caught up with the brand, helping to explain the rapidly revolving door of different distributors that represented it, and it was no great surprise when the company collapsed in 2009. That’s the point where Dantax, a longstanding and extremely successful Danish audio brand (they established and ran Scan-Speak for twelve years in the late 1970s and early 1980s) brought the company’s assets out of administration, re-employing the original design team two weeks later.
Their first order of business was to stabilize the brand, bringing organization to the market and consistency to production, dealing with the mountain of accumulated customer issues and broken products — even to the extent of retooling and reproducing new drivers for the earliest models that had been left unserviceable. That was always going to be a long and involved process, but ultimately the brand achieved a degree of stability and restored trust in the marketplace. Meanwhile, improvements in manufacturing consistency and a first round of crossover changes, the result of input from established, in-house engineers at Dantax, produced the .1 models, speakers that finally started the move toward a more consistent and balanced performance — albeit retaining the odd idiosyncrasy, like four loosely coupled and non-adjustable feet, thus ensuring that one was always going to rattle.
Dantax also took the opportunity to leverage much of the thinking and technology inherent to the Raidho line into a far more affordable range, the Scansonic MB series. Starting at around €1500 for a pair of compact stand-mounts and reaching up to the €10,000 mark for the slender, seven-driver, three-way MB-6, these offered considerably more than a taste of the Raidho recipe — for a fraction of the price. With Dantax input from the start, they also offered a far more consistently balanced voice across the range.
It was finally time to really rework the designs, bringing the best out of the still-evolving technology, while eliminating the engineering flaws that marred their performance. It soon became apparent that several of those flaws were firmly lodged in the DNA of the original design team, a philosophical disconnect that soon led to a final and irrevocable divorce, leaving the development of the brand, the existing models and the unique technology embodied in the driver diaphragms and basketless motor assemblies (where the supports or “legs” that support the motor bolt directly into the back of the baffle, the cone surround glued directly to its front face) firmly the responsibility of Dantax and their design team.
The first fruits of their efforts were the .2 series speakers, a really significant advance over the .1s and a seriously promising start, swiftly followed by the XT-5 (€35,300 or €39,800 per pair, depending on finish), the brand’s first new model designed entirely by the Dantax team. Featuring the latest iteration of the ceramic sandwich cones that had always featured on the bass and midrange drivers, these boasted seven layers including dual plasma-deposited titanium “‘skins” on both sides, significantly improving both the stiffness and self-damping of the diaphragm itself. The speaker was a conspicuous success, and for a while, this tall, elegantly sculpted model positioned at the top of Raidho’s entry X series was also their best-sounding floorstanding design, despite the significantly more expensive models available further up the range.
Which brings us almost up to date — and the start of the latest chapter in the Raidho story. In December 2017, Dantax acquired another, long-established Danish audio company Gamut. With a well-respected range of both high-end electronics and speakers already on the market, the real significance of this move was to bring Gamut’s owner/designer under the Dantax umbrella, Benno Baun Meldgaard (above right) being just the man to take the Raidho project to the next level. Cutting his teeth on the Scansonic MB series offered him the opportunity to get to grips with the technology and crossover topologies, to grasp the design philosophy that had also generated the Raidho products. With the revised MB-B series put to bed, it was time to turn his attention to the core product range and take on the challenge of the Raidhos proper.
A recent trip to the Dantax/Raidho factory in Aalborg, Denmark, gave me a chance to catch up with both CEO Peter Jensen (above left) and Benno, to get a status report on the “Raidho project” and a look and a listen to the latest fruits of their labors, in the elegantly sculpted form of the new TD4.2 (€107,000 or €125,000 per pair, depending on finish), debuted at Axpona.
The ‘4.2 an interesting choice of subject for a makeover. The discontinued D4.1 was the darling of the expensive D series, by far the prettiest and also amongst the better-sounding of the larger Raidho speakers. Walking into the factory listening room, I noted that the elegant proportions and attractive curves remain unaltered on the ‘4.2, with only the finer details betraying any changes to the practiced eye. There are new terminals on the rear — that thankfully now allow you to tighten spade connections properly, while arguably even more subtle but much more significant is the switch to the outwardly almost identical TD (tantalum/diamond) cones first seen in the TD4.8 (€134,000 or €149,000 per pair, depending on finish) at Munich last year, in place of the original’s D-series diamond ones. If the presence of those new drivers suggests a significant departure from the original model, it’s a suspicion that is quickly and emphatically confirmed by the sound.
Listening to the new speaker, it is immediately obvious that this is a far more integrated, communicative and confident performer. With serious scale now present to back up the always impressive dynamics, with genuine low-end extension and weight to underpin the musical contrasts and drama, as well as offering some much needed dimensionality, the TD4.2 suddenly got all grown up. Sloughing off the shock value of hyped dynamics and the uncouth interjections of a lumpy, detached bass, what was always one of Raidho’s more refined three-ways has been sent to finishing school. It’s most obvious on simple material, the sort of naturally miked recordings that immediately reveal disturbances in the linearity or energy spectrum of the loudspeaker. Playing the Janis Ian track “Some People’s Lives” (from the gold CD of Breaking Silence [Analogue Productions CAPP 027]), the TD4.2 — driven by a suite of Gamut electronics — really captured the natural perspective, dimensionality and presence of this crossed-pair recording, the fragility in the vocal and the deft phrasing, hesitations and vocal inflexions that make this song so powerful. It’s a performance that demonstrates the improved integration, control, phase coherence and overall musical clarity that now define this speaker. The XT-5, which I had for review, demonstrated the sheer resolution and impressive dynamic range of the second-generation Raidho drivers, but the TD4.2 adds significant bandwidth, scale and color to the mix, arguably the first Raidho that really lets the music breathe. This is a first impression that is reinforced the more material I listen to, the bigger and more demanding that material becomes.
But what is perhaps most significant is the way those attributes allow the speaker to fasten on the performance as opposed to the quality of the recordings being played. Playing the Giulini/CSO recording of Mussorgsky’s Pictures (from the Giulini In Concerto boxed set [Deutsche Grammophon Gesellschaft 4829510]) underlined just how comfortable the TD4.2 was with large-scale works and towering crescendos, demonstrating its sudden dynamic response and revitalized tonal palette. The percussion had a real snap to it, while the Chicago brass was its richly ripping self, bringing the character of both the orchestra and this performance to the fore — despite the less-than-brilliant recording. Once again, something that was apparent with the XT-5 has been reinforced and writ large with this bigger, more expensive and more complex speaker, which suggests good things about the integrity of the underlying engineering.
Speaking of engineering, just what changes have been made to the original design? Starting with the drive units, both the cone drivers (4 1/2″/115mm bass and 4″/100mm midrange) now have the latest seven-layer tantalum/diamond diaphragms, while the instantly recognizable Raidho tweeter has also been significantly modified, sharing only the diaphragm and faceplate of the original design. The magnet system and rear chamber are entirely new, reducing resonance in the critical area behind the diaphragm by 35dB and improving sensitivity by 2dB. So, perhaps it would be a good time to define terminology when it comes to Raidho-speak. Right from the word go, a big part of the Raidho story has been their distinctive cone technology. Original models used what the company referred to as a “deep ceramic” process to create their cones. This consisted of a surface penetration treatment that started with an aluminum cone and ‘ate’ ceramic skins onto its surface, creating a three-layer sandwich with ceramic front and back and a softer aluminum core in the middle. By controlling the depth of the ceramic skins, the self-damping behavior of the cone could also be influenced or improved, if not fully controlled. The next step was the creation of the so-called Diamond cones. These added an additional plasma-deposited diamond skin over the ceramic layer, stiffening the cones still further. But performance has since taken another step up with what I refer to as the second-generation cones. Like the Diamond cones, these add additional layers to further control the mechanical behavior of the cones. In the case of the more affordable XT series, that means two additional plasma-deposited titanium layers on each side of the cone, creating a seven-layer sandwich which is both stiff and lightweight, but also extremely well-behaved, with first break-up mode well outside the pass-band — although more on that in a moment. The TD drivers, destined for the flagship line suffer less cost constraint, and can thus indulge in more exotic materials. In this case, that takes the form of adding a thin layer of Tantalum (a dense, stiff but ductile material) between the ceramic sandwich cone and the outer Diamond skin, a development that improves self-damping significantly but also allows the use of a higher intensity plasma for the deposition of the diamond layer, increasing the proportion of diamond to carbon and the stiffness of the finished cone. So when Raidho talk diamond drivers, they mean something very, very different to the pure diamond tweeters used by other manufacturers, or the pure diamond midrange drivers employed in the Tidal La Assoluta and Akira. They are also talking about a unique technology and, critically a technology that scales more easily and cost-effectively than pure diamond diaphragms. What price a diamond bass driver? A lot less in the case of a Raidho sandwich cone, something that already exists.
But the evolution of the TD4.2 involves far more than just new driver diaphragms. The cone drivers now have high-impedance motors, allowing them to be connected in parallel, delivering far greater control from the amplifier, while a rising impedance characteristic on the system, as a whole eases the amplifier load and reduces distortion. The crossover has been completely reengineered, with compound slopes to eliminate out-of-band artifacts produced by the drivers (those break-up modes might be high, but they are still there) and revoicing to reflect a four-meter listening distance rather than the one-meter measurement standard. When I visited, final voicing was just being completed, with flat-plan crossovers laid behind the speakers, complete with spring clips to connect the key components, allowing for quick and simple value changes. Those crossovers may bear little physical resemblance to the layout or hardwired construction of the production items, but they provide a fascinating insight into the speaker-development process.
Finally, the internal arrangement of the cabinet has been significantly revised. The braces and baffle surrounds have been shaped and refined to improve internal airflow and reduce reflective surfaces close to the drivers, while the amount of internal absorption has been reduced. But more importantly the distribution has been adjusted, placing absorption where it is most effective, especially when it comes to the escape of internal energy through the driver diaphragms themselves. The result of all these changes is a far clearer, more directed and purposeful performance. Resolution of detail has improved, but so has its presentation, so that the sound isn’t just more impressive; it is also more musically informative, making it easier to decipher the sense of space and the performance itself.
That newfound clarity and relaxed sense of order are what brought the impressive dimensionality, presence and emotional impact to the Janis Ian track. But they are also what allowed the Mussorgsky to impress and engage, along with other familiar recordings of Tchaikovsky and Beethoven, Elgar and The Cure. Cleaning up the speaker’s performance by minimizing spurious output and making the amplifier’s task easier, too, really let’s you appreciate the musical benefits of the improved drivers. The elimination of out-of-band elements echoes work carried out by Focal on their Utopia Evo series, with similar improvements in system clarity and rhythmic articulation, while the crossover improvements keep things naturally balanced. Overall, it’s an impressive step up in musical performance that if it is applied across the range (and the new TD1.2 was also shown at Axpona) promises to revitalize the entire Raidho family.
But that was only half the story. Lurking in one corner of the production area was a pair of cabinets that were both recognizably Raidho but also distinctly different. With the same boat-backed construction and outrigger legs, the as-yet-unnamed new model is shorter and squatter than its brethren. The MTM array at the top of the cabinet is positioned above a pair of 200mm/8″ bass units, making for a far more familiar-looking speaker, one that might lack the fine lines and statuesque appeal of the TD4.2 but offers a more muscular, powerful look instead.
But the real story lies inside, with the first major revision to the motor structure and basket of the Raidho drivers — and an interesting development in magnetic topology to boot. In the original driver design, the underhung voice coil and its circumferential array of neodymium bar magnets was mounted on a flat plate that in turn sat on five standoffs that spaced it from the front baffle. Given the energy that has been expended in the TD4.2 on eliminating internal reflective surfaces immediately behind and around the drivers, it should be no surprise that the substantial flat plate sitting immediately behind the baffle was an immediate target for improvement. Compare the basket structures of the new and old driver designs side by side and the success with which this has been achieved is immediately apparent. The five, curved legs and aerodynamically shaped motor are like something out of science fiction compared to the Meccano meets Lego construction of the original. What’s less obvious is that achieving that elegantly compact magnetic structure, with its smooth external contours, demanded the creation of a completely new (now patented) magnetic circuit, one in which four curved plates form a thin-walled magnetic tube, a stark contrast to the massive discs more often seen on the back of high-powered drivers. Incredibly, the final, elegantly profiled motor module is an entirely fixing free assembly, the parts simply pushing into place.
The revised magnetic system is more than just a pretty face. As well as being compact and incredibly solid, it is also extremely powerful, delivering a 1.1 Tesla flux density in the motor’s magnetic gap — very impressive for an underhung arrangement. The parts count has also been dramatically reduced and, in combination with the sheer density of the construction, that should result in much better mechanical behavior, promising lower driver resonance and reduced mechanical signature. And besides that, it looks really cool too. Sometimes things just look right and this is definitely a case in point. Of course, Raidho is far from the first company to tread this path, but they are certainly taking the issue seriously and have delivered a solution that’s as innovative as it is impressive. Nor are the driver refinements limited to the midrange and bass units (both of which receive the new motor and standoffs). As well as the tantalum skin added to its diaphragm, the tweeter will benefit from a beefing up of the perforated plate that sits behind the diaphragm, while the flow holes have been profiled to limit turbulence in the cavity behind the membrane.
Just as the XT-5 represented the first clean-sheet design combining Raidho’s technology with the Dantax engineering team, this new model marks another watershed — the first clean-sheet design that’s been entirely supervised by Benno Baun Meldgaard. You can be sure that Raidho’s room at the Munich show is on my list for an early visit.