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Raidho Acoustics D-5 Loudspeaker

Raidho Acoustics D-5 Loudspeaker

If you’d like to hear all that is right about my current reference loudspeakers, the majestic, seven-driver, three-way Raidho D-5s, put on the Feria from Ravel’s Rhapsodie espagnol [RCA LSC-2183]. If you want to hear the very little that is wrong with them, play the same thing.

This is a recording with gorgeous string and wind tone— among the best on any RCA (and now even better on the Analogue Productions 200-gram LP reissue). But even the most silken strings and winds can turn a little rough-sounding when dynamics go way up—and part of what makes the Feria so delightful is that, after three languid movements, Ravel does dial dynamics up in his festive finale, starting with those dancing, dotted rhythms on piccolo and flute, proceeding to leaping mezzofortes on clarinets and bass clarinet with colorful harp and string glissandos, ebbing into swirling orchestral decrescendos that are like a great gathering of breath before the culminating exhalation of the crescendos, in which everything (winds, horns, trumpets, trombones, timpani, castanets, gong, celesta, strings, even a sarrusophone) sounds its glorious, floor-shaking note.

The trick with any stereo system is to reproduce all this—the individual voices, the murmurous decrescendos, and the explosive tuttis—while maintaining a concert-hall balance, i.e., without tipping into harshness or excess brightness on piccolos, flutes, strings, horns, and trumpets on fortissimos, or into muddiness on cellos, doublebasses, and timpani on pianissimos.

The D-5s can do this essential trick with even more sensational clarity, beauty, power, and realism than the Overall Product of the Year Award-winning Raidho C-4.1s I reviewed in Issue 236.

Raidho Acoustics D-5 Loudspeaker

But, as was also the case with the C-4.1, you do have to pay an occasional price in midbass definition and control for all this musical largesse. In a little patch between about 60Hz and 80Hz—precisely where the doublebasses in the Feria occasionally play ostinatos—the D-5s can (can, mind you) sound plumper and somewhat less well defined than they do everywhere else. (Such excess midbass is common in ported loudspeakers, and I’ll have more to say about how to deal with it in my sidebar on setup.)

Raidho’s new flagships, the D-5s don’t so much replace my previous references, the C-4.1s, which are still in the C Series line, as exceed them in technological sophistication, performance, and cost. Though the two pairs of speakers look nearly identical— tall, svelte, ported, D’Appolito floorstanders with four mid/ woofers (two on top, two on bottom), two midrange drivers (one on top, one on bottom), and a single quasi-ribbon tweeter midway between—they are, in fact, substantially different. For one thing, the C-4.1s use aluminum-oxide ceramic diaphragms for their mid/woofs and midranges; the D-5s use extremely costly diamond/carbonite ones, made for Raidho at the Physical Vapor Deposition (PVD) Laboratory of the Tribology Center of the Danish Technological Institute in Aarhus. (The Tribology Center is dedicated to finding practical commercial applications for the ideas developed at the Technological Institute. Its PVD Lab is equipped with advanced machinery capable of depositing a layer of diamond on the membranes of Raidho’s drivers. Obviously, this kind of science and the equipment needed to execute it is well beyond the means of hi-fi companies, save in Denmark, where the government and the universities work in concert with small manufacturing firms. Of course, use of the Tribology Center doesn’t come for free. Companies like Raidho have to pay a sizable fee for the services of the PVD Lab. Nonetheless, the fact that a small company can access such a state-of-the-art facility is remarkable.)

What are the advantages of diamond/carbonite diaphragms? They are harder and stiffer than diaphragms made from any other material, which means, at least in theory, that they will remain linear and distortion-free up to a much higher frequency than ceramic cones (the second hardest, stiffest material). Where Raidho’s C Series midrange drivers have a peak breakup of 3-4dB at 12.5kHz, its D Series midrange driver doesn’t peak at the same amplitude until well above 20kHz, a full octave higher.

Why does this improved pistonic behavior matter? Because the higher in frequency a midrange’s breakup modes fall, the less likely those modes will add distortion to the sound of the tweeter. In the case of Raidho speakers, this is especially critical, since the tweeter is an extremely low-mass sealed-ribbon, whose own distortion levels are minimal.

 

One of the few problems with past iterations of Raidho speakers has been a slight discontinuity in the crossover range between the ribbon and the ceramic midrange units, owed in part to the midrange drivers’ breakup (and also to the different dispersion patterns of the line-source tweeter and the point-source cones). Though Raidho attempted to disguise this problem by engineering a trough into the crossover region, the fix wasn’t completely successful in either the C-4.1 or the two-way C-1.1 stand-mount. With the new diamond diaphragms in the D-5s (and the two-way D-1s, which I will report on separately), the tweeter and the midrange drivers blend seamlessly.

Those of you familiar with the Raidho line will be able to hear the difference that the diamond drivers make immediately. Though the speaker’s warm, sweet, concert-hall-like balance remains fundamentally the same as that of the C-4.1, the D-5’s upper mid-range and treble are smoother, and the speaker’s overall presentation is more of a piece from top to bottom. In addition, transient response, density of tone color, and low-level resolution have been audibly improved (and lest you’ve forgotten, the C-4.1s were the fastest, most beautiful-sounding, highest-resolution full-range speakers I’d heard in my home at the time that I reviewed them).

The result is a ribbon/cone loudspeaker that is a benchmark in its combination of simply gorgeous tone color, tremendous dynamic range and ease, lightning speed, panoramic soundstage width, depth, and height, and nearly unrivaled inner detail. On big moments, such as the Basie orchestra going for broke in “Street of Dreams” from Sinatra At The Sands [MoFi], or Chris Frantz’s incredibly powerful drumming at the close of “Life During War-time” (or Tina Weymouth’s sensational bass riff at the start of “Take Me to the River”) from Stop Making Sense [Sire/Warner Brothers] or the staggeringly powerful tuttis in the aforementioned Rhapsodie espagnol, the sheer acoustical power that the D-5s are capable of generating comes closer to the power of an actual big band or rock drumkit/Fender bass or symphony orchestra than anything I’ve heard in my home. (If you’re into power music of any stripe, this is certainly a speaker for you.) At the same time the D-5 never loses track of individual instrumental timbres and textures, making small-scale music such as the violin and piano on George Crumb’s Four Nocturnes [Time] come alive like nothing else I’ve auditioned. To hear the way the D-5s capture violinist Paul Zukofsky’s pizzicatos, harmonics, and glissandos on harmonics is to hear both Zukofsky’s incredible musicianship and Crumb’s extraordinary musical imagination with matchless clarity and beauty. No matter how loud or soft the music gets, these Raidhos will reproduce timbral, textural, dynamic, performance, and compositional details with unexcelled high fidelity.

Although the D-5’s presentation has been artfully tailored to the ear (for which, see below), it is nonetheless exceedingly faithful to the sound of the real thing. For example, I recently had an experience that few reviewers get to enjoy. Forgive me for bragging, but because my listening room sounds unusually good—as it damn well should after ten years of tinkering—our Music Editor Mark Lehman, who is also an accomplished composer with several pieces on CD, and his gifted engineer Mark Milano decided to record Mr. Lehman’s duo for violin and viola, Sephardim—Variations on Three 14th Century Sephardic Melodies, in my digs.

Though I’ve been to many recording sessions, never before have I had the opportunity to hear a piece played live—and then played back a few minutes later from the digital master—in my very own room. It was a unique occasion, and I’m delighted to report a highly elucidating one, as the recording of viola and violin played back through the Raidho D-5s (powered by Soulution electronics and hooked up with Synergistic Research cables) came so close to what that same violin and viola had sounded like in the actual performance that both of the performers were astounded (and the two Marks so delighted with the sonic results they plan to record again in my room in the near future).

Here, for once, was an A/B test that made sense. And the Raidhos passed it with such high fidelity and extraordinary realism that even I was taken aback. (At one point during the session the two performers were recorded talking to each other between takes. In playback through the D-5s their voices were so “there” that both Mark Milano and I, who at that moment had our backs turned to the speakers, thought the two ladies had returned to the listening room to chat, until we turned around and realized that we were hearing them through the D-5s!)

How has Michael Børresen, Raidho’s world-class speaker-designer, managed a magic trick this astounding? The answer is by putting psychoacoustics ahead of acoustics—by making the way we actually hear music in real venues his prime engineering goal. Børresen’s formula is simple and logical: Since our ears are most sensitive in the 1–7kHz range and least sensitive in the 20Hz– 100Hz region, Børresen deliberately reduces energy in the presence and brilliance ranges and boosts it in the mid-to-upper bass, voicing his speakers to sound flat to the ear rather than to measure flat to a microphone.

I suppose you could argue that this is a form of signal processing, but the results speak for themselves. Through the D-5s everything from the driest Columbias to the most glorious RCAs sounds considerably lovelier and more listenable, and—thanks to the D-5’s superb resolution, transient speed, and dynamic range— more astoundingly lifelike. While it is also the case that instruments with fundamentals or partials in the upper midrange and lower treble—such as strings, winds, and piano—will sound a tiny bit more recessed (in the sense of imaging slightly farther back on the stage) as a result of Børresen’s voicing, to my ear his approach takes absolutely nothing away from the illusion of hearing the real thing. On the contrary, it actively benefits certain instruments that can (and do) turn bright, edgy, or brittle on flatter-measuring speakers (particularly speakers with beryllium or diamond tweeters) at higher volumes. Although I’m at heart a transparency-to-sources listener, there is something so irresistible and—as listening to Mr. Lehman’s duo memorably proved—so breathtakingly realistic about the D-5’s “psychoacoustic” balance that I’ve come to prefer its tailored-to-the-ear sound to that of many textbook-accurate transducers.

 

The D-5s way with bottom octaves, as I noted at the start of this review, is somewhat more of a mixed blessing.

As was the case with the C-4.1s, I am of two minds about the D-5’s low end. On recordings that don’t over-excite its midbass— including several that I’ve already mentioned—the D-5’s slam, speed, and resolution in the bottom octaves are breathtakingly realistic. Be it a bass drum, a timp, a tom, a piano, a big band, or a full orchestra, this speaker is, as I’ve already said (but it’s worth repeating, as this is one of those things you really need to hear for yourself), more capable of moving air in the way such instruments and ensembles do in life than anything else I’ve heard in my home (or anyone’s home). The D-5’s power in the low end—matched as it is by the same gorgeous timbre and texture that you hear everywhere else—is simply addictive, and highly realistic.

At the same time, given the right (or should I say wrong) recording, the D-5 can sound overly generous on certain pitches. Although Raidho has installed a subchamber in its ports that boosts energy at lower volumes and smooths it at higher ones (and I do hear the improvement this makes in timbre, texture, and clarity over the C-4.1 in the bottom octaves and power range), the D-5s can still, on occasion, generate a bit too much of a good thing. Take Louis and Ella [Analogue Productions/Verve], for example. Though the D-5 is simply superb on both singers’ voices—making them sound in-the-room-with-you “there”—a few of Ray Brown’s bass notes give them fits. Now I’ll grant that this is not the best recording of acoustic bass, but that doesn’t really matter. When presented with repeated notes (played with high energy) in the 60–80Hz range, be it Brown’s bass fiddle or Norman Keenan’s on Sinatra at the Sands or David Piltch’s on Holly Cole’s Temptation [Capitol] or (some, not all, of) the doublebass ostinatos of the Feria, the D-5 can sound the way it never sounds elsewhere—a bit overly resonant and less than clearly defined.

Allowing for its tailored-for-the-ear balance, this extremely large speaker disappears as a sound source in virtually every way, save for these occasional anomalous midbass freak-outs. (The odd thing is that you don’t hear this loss of grip elsewhere in the bottom octaves, and you don’t even hear it in the 60–80Hz range with certain instruments, such as piano or percussion. Go figure.)

Of course, some of this problem is owed to my modestly sized room. (To be fair I’ve had the same issue with other large floorstanders.) Just understand that—as was the case with the C-4.1—you’ll have to spend more than the usual amount of time treating your listening room to hear the D-5s optimally.

Having said this, let me add (as I did in my review of the C-4.1) that I, for one, would not want to trade away all that the D-5s do so persuasively well in the low end—their genuinely lifelike speed, power, color, texture, and pace—for leaner, flatter, more stinting bottom octaves. It may sound weird coming from me—or from any reviewer—but I can live with the few low-pitched notes (and there are only a scarce few once you’ve set them up properly in a properly treated listening space) that the D-5s get “wrong” for the vast majority they get right. When all is said and done, this is simply the most beautiful, powerful, and lifelike speaker I’ve heard, no matter the music or the level. I know I said the same thing about the C-4.1, but their genes are the same, the difference being that the D-5 is unquestionably an improvement over its less expensive brother.

Speaking of expense…the Raidho D-5 lists for $220,000 the pair.

Let me give you a moment to digest that.

Yes, their diamond-diaphragm drivers cost a lot of money to make (and it is that extra money that makes the difference in their price tag). And, yes, the D-5 is audibly superior to the C-4.1, and to every other large dynamic floorstander I’ve audtioned. But the $140k C-4.1 is still a great loudspeaker—one that I could easily live with. And there are a whole lot of other great loudspeakers from Wilson, Magico, Rockport, YG, etc. at or around or in-between or far beneath this extravagant price.

Even though the D-5s are the most consistently thrilling, fool-you-realistic full-range dynamic loudspeakers I’ve yet heard, and are certainly worth the effort it will take to make them sound their best, $220,000 is a pile o’ dough. Thus, you (that is, the one or two of you I’m still addressing) will need to do considerable comparison-shopping and arrange for a lengthy audition before pulling out that Rubidium MasterCard. At such a price point, personal taste is going to be determinative, and nobody can make such a choice for someone else.

This I can tell you: Given the right room treatment, setup, amplification (Soulution’s new 700 or 500 Series or Siltech’s wonderful SAGA system or Constellation’s Performance Series), and source (Walker Proscenium Mk V, United Home Audio Phase 11S OPS, Berkeley Audio Reference DAC, or Mark Milano’s mastertapes), the D-5s certainly suit my taste to a tee, which is precisely why they’ve become my full-range reference loudspeakers and are leading contenders for TAS’s 2014 Ultra-High-End Loudspeaker of the Year Award come January. If you’ve got the dough and the permission to spend it, they belong at the top of your must-hear list.

SPECS & PRICING

Type: Three-way, five-driver dynamic floorstanding loudspeaker
Drivers: Four 160mm diamonddiaphragm woofers, two 100mm diamond-diaphragm midrange drivers, one sealedribbon tweeter
Frequency response: 25Hz–50kHz
Impedance: 5.8 ohms
Crossover: 150Hz and 3kHz, second-order
Amplification: >50W
Dimensions: 250mm x 2010mm x 670mm
Weight: 165 kg
Price: $220,000

RAIDHO ACOUSTICS
co/ Dantax Radio A/S
Bransagervej 15
9490 Pandrup
Denmark
raidho.dk

JV’s Reference System
Loudspeakers: Raidho D-5, Raidho D-1, Avantgarde Zero 1, MartinLogan CLX , Magnepan 1.7, Magnepan 3.7, Magnepan 20.7
Linestage preamps: Soulution 520, Constellation Virgo, Audio Research Reference 10, Siltech SAGA System C1, Zanden 3100
Phonostage preamps: Audio Research Corporation Reference Phono 10, Innovative Cohesion Engineering Raptor, Soulution 520, Zanden 120
Power amplifiers: Soulution 711, Siltech SAGA System V1/P1, Constellation Centaur, Audio Research Reference 250, Lamm ML2.2, Zanden 8120
Analog source: TW Acustic Black Knight, Walker Audio Proscenium Black Diamond Mk V, AMG Viella 12
Tape deck: United Home Audio UHA-Q Phase 11 OPS
Phono cartridges: Clearaudio Goldfinger Statement, Ortofon MC A90, Ortofon MC Anna, Benz LP S-MR
Digital source: Berkeley Alpha DAC 2
Cable and interconnect: Synergistic Research Galileo LE, Crystal Cable Absolute Dream, Anzus Diamond
Power Cords: Synergistic Research Galileo LE, Crystal Cable Absolute Dream, Anzus Diamond
Power Conditioner: Synergistic Research Galileo LE, Technical Brain
Accessories: Synergistic ART and HFT/FEQ system, Shakti Hallographs (6), Zanden room treatment, A/V Room Services Metu panels and traps, ASC Tube Traps, Critical Mass MAXXUM equipment and amp stands, Symposium Isis and Ultra equipment platforms, Symposium Rollerblocks and Fat Padz, Walker Prologue Reference equipment and amp stands, Walker Valid Points and Resonance Control discs, Clearaudio Double Matrix SE record cleaner, Synergistic Research RED Quantum fuses, HiFi-Tuning silver/gold fuses

Tags: RAIDHO

Jonathan Valin

By Jonathan Valin

I’ve been a creative writer for most of life. Throughout the 80s and 90s, I wrote eleven novels and many stories—some of which were nominated for (and won) prizes, one of which was made into a not-very-good movie by Paramount, and all of which are still available hardbound and via download on Amazon. At the same time I taught creative writing at a couple of universities and worked brief stints in Hollywood. It looked as if teaching and writing more novels, stories, reviews, and scripts was going to be my life. Then HP called me up out of the blue, and everything changed. I’ve told this story several times, but it’s worth repeating because the second half of my life hinged on it. I’d been an audiophile since I was in my mid-teens, and did all the things a young audiophile did back then, buying what I could afford (mainly on the used market), hanging with audiophile friends almost exclusively, and poring over J. Gordon Holt’s Stereophile and Harry Pearson’s Absolute Sound. Come the early 90s, I took a year and a half off from writing my next novel and, music lover that I was, researched and wrote a book (now out of print) about my favorite classical records on the RCA label. Somehow Harry found out about that book (The RCA Bible), got my phone number (which was unlisted, so to this day I don’t know how he unearthed it), and called. Since I’d been reading him since I was a kid, I was shocked. “I feel like I’m talking to God,” I told him. “No,” said he, in that deep rumbling voice of his, “God is talking to you.” I laughed, of course. But in a way it worked out to be true, since from almost that moment forward I’ve devoted my life to writing about audio and music—first for Harry at TAS, then for Fi (the magazine I founded alongside Wayne Garcia), and in the new millennium at TAS again, when HP hired me back after Fi folded. It’s been an odd and, for the most part, serendipitous career, in which things have simply come my way, like Harry’s phone call, without me planning for them. For better and worse I’ve just gone with them on instinct and my talent to spin words, which is as close to being musical as I come.

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