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Raidho D-5.1

Raidho D-5.1

“New and improved” components can be found everywhere in high-end audio (and everywhere everywhere else, for that matter). Generally speaking, most of them are improved—maybe not a whole lot or in every regard, but usually enough to justify contemplating an upgrade.

The new version of Raidho’s D-5 flagship, the $225k D-5.1, isn’t one of these.

Despite the modesty of that measly “.1” added to its moniker, the D-5.1 is in key ways one of the most dramatically improved speakers I’ve heard—right up there with the Magico Q1 (compared with the Magico Mini One/Two) and the MartinLogan CLX (compared to the ML CLS/CLZ). Indeed the D-5.1 is so much better—and so different—than the D-5 that its presentation will initially require some “expectation adjustment” from those of you used to the dark, distant, hard-hitting, ravishingly lovely and realistic Raidho sound.

To refresh everyone’s memory, the D-5 was the first Raidho flagship to use vapor-deposited (over ceramic) diamond/carbonite diaphragms in both the midrange and the bass—the stiffness and linearity of which were claimed to exceed that of other cones. As was the case with Raidho’s excellent, now-discontinued C-4.1, which the D-5 superseded, these midrange and bass drivers were mated with Raidho’s superb single-ended ribbon tweeter (IMO, one of the finest treble transducers in the high end) in a three-way D’Appolito array comprising four 8″ woofers (two on top and two on the bottom of the D-5’s beautiful, exceptionally svelte, dual-front-ported cabinet), two 4.5″ midranges (one above and one below the central ribbon tweet), and the sealed ribbon itself in the middle of this WMTMW configuration.

Because of differences in transient speed, resolution, sensitivity, and radiation pattern, seamlessly mating a ribbon (or an electrostat) with a cone driver has always been a tough order. (Some would say impossibly tough.) But in the D-5 Raidho managed to execute it as well as anyone has, thanks in part to the lower-amplitude breakup modes of the new diamond/carbonite cones and in part to a little crossover trick that folks often play when pairing quasi-line-source drivers with point-source ones. To wit, to disguise differences in radiation pattern, speed, and resolution and to eliminate the upper midband/treble roughness of residual breakup modes, Raidho built a trough into the region where the diamond midrange crossed over to the ribbon tweet. Happily, this broad smooth dip in frequency response (which is quite measurable) fell precisely in the area where the ear is most sensitive to sounds (and therefore least affected by a lowering of volume)—the so-called “presence range” between about 1.5kHz and 8kHz. To balance out this trough and further tailor the presentation to our hearing, Raidho built a broad rise into the bottom octaves, where we are least sensitive to sounds (and most affected by volume level), producing a “designed-for-the-ear” balance that was anything but flat but which, was, nonetheless, ravishingly sweet, beautiful, and lifelike on most recordings.

However, as I pointed out in my original D-5 review, all was never completely well with Raidho’s flagship. It is one thing to claim that your speaker has a built-in frequency response that is “designed for the ear”; it is quite another to stick such a speaker in an average listening space, where room modes cause sizeable dips and peaks in speakers that measure flat, much less those that are (deliberately) engineered not to measure like a ruler.

Raidho D-5.1

In particular, in my room (and in other venues where I’ve heard it play) the D-5 simply had way too much bass. While the broad plateau and double-digit peak at port resonance that are built into the D-5 in the low frequencies could and did add visceral excitement and sensational impact to many recordings (such as my 15ips dub of the mastertape of Michael Jackson’s “Black or White”), they could also grotesquely distort the sound of something as simple as Norman Keenan’s standup bass on MoFi’s great reissue of Sinatra at the Sands. It all depended on where the instrument was playing and how long that tone was sustained. If, as is the case with the Sinatra recording, a bass fiddle had substantial energy around 50–60Hz, the combination of port resonance and elevated overall response would produce a peakiness so substantial it could literally make my room ring. In addition, the trough in the presence range further darkened timbre and greatly reduced immediacy, throwing vocalists and instrumentalists who should have been front and center a yard or so behind the plane of the speakers. At the same time, thanks to the bass-range plateau, drumkits, doublebasses, Fender bass, timps, and other low-pitched instruments sounded more forward than they should have. In short, when it came to staging and imaging the D-5 was anything but a “fidelity to mastertapes” kind of speaker.

As noted in my review, I did everything I could in the way of passive room treatment to fix the port problem, and while I could reduce its effect I could never eliminate it. (Synergistic Research’s Vibratron, part of its ART system, helped substantially with the presence-range issue.)

At this point you may justifiably wonder why I stuck with such a flawed speaker, much less used it as a reference. The answer is that above and below port resonance, the D-5 was so realistically powerful, well defined, and hard-hitting in the bass that I could live with the occasional aberrant G#1, A1, A#1, or B1, while the sonically attractive concomitant of the speaker’s recessed presence region was greater stage depth and image focus and less room interaction (i.e., brightness) in the upper-mids and treble.

Do not forget that the D-5 was (and is) an extraordinarily high-resolution loudspeaker with an uncanny ability to tease out little nuances of timbre, dynamic, and texture that other speakers simply don’t reproduce. When you combine that resolution with tremendous dynamic clout, unexcelled transient speed, simply gorgeous tone color, and a butter-smooth treble, you get a level of excitement, beauty, and realism on well-recorded music that becomes, in the words of my friend and colleague Andre Jennings, “addictive.”

 

Let’s face it: No speaker—no stereo system—is perfect. There are always trade-offs, and the trick is to find the ones you can live with longer term. Most of the time I could live with the downside of the D5s because—bass and presence-range issues notwithstanding—its upside was so substantial that it sounded exceptionally good on every kind of music, from small-scale acoustic to the hardest and noisiest of hard rock.

And then along came the Magico M Pros.

It is a sad fact that all you need to do to become increasingly aware of (and annoyed by) the flaws of a component you love is listen to a component that doesn’t have those flaws. Of course, that new component doubtlessly has its own issues, which you will discover over time, but at first its problems are not what you hear. At first what you hear is what your new flame is getting right and your old one isn’t.

A superbly engineered and built, superbly measuring loudspeaker, the M Pro was kind of the anti-Raidho D-5. Though sweet and lovely in timbre, it was not dark or bottom-up in balance like the D-5; instead, it had what might be called a warm, sunny neutrality—far more gemütlich than a typical Magico of yore. Though deep in staging and well-focused in imaging (albeit not as deep or as tightly focused as the D-5), the M Pro had no suck-out in the presence range or darkness in the brilliance range, making closely miked or centrally miked vocalists, like Ella Fitzgerald and Louis Armstrong on Analogue Productions’ superb 45rpm reissue of Ella and Louis, sound the way they were recorded—upfront and almost tangibly “there”—and making little nuances of articulation (such as Dean Martin’s breath control, or lack thereof, on AP’s benchmark 45rpm reissue of Dream with Dean) every bit as audible as they were through the standard-setting D-5, albeit more immediate in perspective.

Perhaps most importantly, in the bass and power ranges the Magicos didn’t have as much of a plateau as, and nothing like that double-digit peak at port resonance of, the D-5s. (Of course, the M Pros don’t have a port. They are sealed-box—and what a box!—transducers.) Thus, something like Ray Brown’s standup bass on the aforementioned Ella and Louis was beautifully resolved and defined throughout its entire range by the M Pros, where on the D-5 it sounded forward, gigantic, and out of control on certain notes.

No, the M Pros all by themselves didn’t have the horripilating midbass slam of the D-5s (though adding a pair of JL Audio Gothams cured that). And, no, their diamond-coated beryllium dome tweeter didn’t have all the smoothness, sweetness, and astonishing clarity of Raidho’s nonpareil single-ended ribbon tweet. All other things considered, however, the M Pros were simply much less colored than the D-5s, making the Magicos a quintessential “transparency to sources” transducer, with the kind of warmth and naturalness on acoustic music that “absolute sound” listeners crave and (combined with the Gothams) the kind of power and excitement in the bass that “as you like it” listeners can’t live without.


Raidho D-5.1

This is where things stood when Raidho’s Lars Christensen and Michael Børresen showed up in my third floor listening room to “make a few changes to the D-5s.” While the Raidhos weren’t exactly in the doghouse, I certainly wasn’t listening to them as regularly as I once did—or as often as I listened to the M Pro/Gothams.

Since their visit things have begun to even out.

So what’s new and improved in the D-5.1? Allow Mr. Børresen to explain:

“First, the magnet system of the new midrange drivers [the two old midranges are removed and replaced with new units in the D-5.1] has been improved in two ways—both of which aim at reducing as much inductance as possible. To begin with, we insert a copper Faraday cap/ring that efficiently DC-locks the magnetic force field; then we insert a sintered samarium-cobalt ring inside, on the pole piece. These two changes raise the efficiency of the new midrange driver by about 2dB. In addition, though the diaphragm material uses the same diamond composite structure as the old midrange, it is processed longer in the vapor-deposition chamber, making the outer diamond layer about 50 percent thicker.

“The increased efficiency and the vastly reduced driver inductance of the new driver increase midrange rise time by almost two times. (It is literally twice as fast.) This makes the new midranges much better matches to the Raidho ribbon tweeter, allowing us to improve linearity through the crossover region compared to the older D-5.

 

“The much faster midranges prompted a few modifications to the crossovers themselves. We have removed the slightly elevated bass plateau we had on the D-5 and close to eliminated the 2–3dB suck-out we previously needed in the mid/tweeter crossover [to disguise differences in radiation patterns, speed, and resolution and reduce the audibility of breakup modes, as mentioned above]. Now the needed suck-out is less than 1dB.

“Also new in the D-5.1 is an impedance network that prevents speaker wires from functioning as antennas, by keeping inductance, and thus impedance, low (about 8 ohms) in the RF area. Certain cables are actually very good at picking up RF and in some amplifiers this bleeds into the audio signal as haze, grain, or even the sound of a radio station.”

How well do these changes work? As you must’ve already gathered, very well indeed in almost every respect save one.

First, the improvements in the midrange drivers and the reduced suck-out in the crossover region between them and Raidho’s ribbon tweeter produce a very different midrange balance than that of the D-5, one that is, indeed, less dark and recessed and more audibly and measurably linear—more M Pro-like, if you will. (There is a complication here that I will come to in a few paragraphs.) Closely miked voices and instruments are no longer lacking in presence; they now have the immediacy they should have. This isn’t to say that the D-5.1 has lost its phenomenal depth of stage (it hasn’t)—merely that its depth begins at the plane of the speaker instead of behind it.

In addition to this welcome change in timbral balance and perspective—which essentially amounts to a more accurate rendering of what’s on the recording—there is a change in midband speed and resolution (which are pretty closely allied). If you thought (as well you should have) that the D-5 was a fast, high-resolution transducer before the update, wait until you hear it now. On recording after recording, transient, timbral, and textural details are clarified to an extent that is kind of astonishing given the Raidho’s exalted starting point. Vocal harmonies—such as those of Ibrahim Ferrer, Compay Segundo, Alberto Valdés, Omara Portuondo, and Eliades Ochoa on Buena Vista Social Club [World Circuit/Nonesuch] or those of Sharon Robinson, Charlie Webb, Hattie Webb, Roscoe Beck, Bob Metzger, and Dino Soldo on Leonard Cohen’s Live in London [Sony] LP—are so finely reproduced that it is possible to hear (and follow) each singer no matter how complex the mix. This holds true for instrumental lines, as well. Leon Fleisher’s fleet, thrillingly bravura performance of Benjamin Britten’s Diversions Op. 21 for Piano Left Hand and Orchestra (next to Ravel’s Piano Concerto in D arguably the best concertante piece for left hand, and like the Ravel written for Paul Wittgenstein) is that much more bravura when you can hear the articulation of every single note with the kind of clarity that the D-5.1 brings to the table. Orchestration and performance are unraveled—voices and instruments are brought to life—as they only are by great electrostats, ribbons, or the very finest hybrids (such as this one) and cones (such as the M Pro/Gotham).

Thus far, Børresen’s claims for the new D-5.1 were easily verified by listening. Even his assertion that the new speaker have increased efficiency seemed to be the case, as the sound I am reporting on is that of the D-5.1 being driven by the exceptional Zanden Audio Systems Model 9600 monoblock—a 60W Class A tube amplifier directly sourced by Soulution’s superb 755 phonostage (which requires no linestage preamplifier) and by my long-time reference Walker Black Diamond V record player with Clearaudio Goldfinger Statement cartridge. (This, BTW, is a system of sources and electronics you guys should hear.)

However—there is always a “however,” folks—in one critical area the D-5.1 was not improved to the extent that it was in the midrange and lower treble. As you can probably guess, that was in the bass.

Børresen says that Raidho has “removed the slightly elevated bass plateau” (italics added) of the D-5 in the D-5.1, and that may well be. But the company has done little to reduce the massive port resonance that accompanies that plateau in-room. As a result, those bass fiddles still freak out when they play notes in the 50Hz–60Hz range. Oh, they may not set my room a’ringin’ the way they once did, but they still occasionally sound outsized and overblown. Despite catching up in the midrange, in the low end the D-5.1 is a far cry from the M Pro/Gotham.

That’s the bad news. The good news is that this problem, which was virtually unrectifiable in the D-5, can be greatly ameliorated in the D-5.1. All you have to do is add the supplied foam plugs to all four ports of each speaker. (A couple of pairs of those magical and magically effective Stein Music System H2 Harmonizers behind each D-5.1 doesn’t hurt, either.) Where those port plugs rather wrecked the blend of the woofers and the midranges in the D-5, they work wonders in the 5.1, perhaps because the speed and resolution of the midrange has been increased and the bass-range plateau has, indeed, been reduced, making the woofers less prominent.

Of course, using those port plugs does cut down on midbass slam, which is one of the things that the unplugged D-5.1, like the D-5, has galore. OTOH, it removes the vestiges of darkness that otherwise cling to the speaker, giving the D-5.1 a very neutral overall balance and markedly improving low-end coherence and definition. Obviously, to plug or unplug will be a matter of taste (and room size and acoustics). But, to my ear, in my room, the plugged version of the D-5.1 completes the renovation of the D-5, making it a wholly new and truly improved transducer suitable for every kind of listener—accuracy, absolute sound, and musicality. If that isn’t a leap forward, I’d like to know what is.

The cost of upgrading a D.5 to a D-5.1 is $32,000, including a two-day visit from Lars and Michael, who perform the upgrade on the spot (so there’s no down time) and make sure everything is up to standards. In my opinion, those lucky few of you who own D-5s would be foolish not to invite the boys over.

In the world of ultra-high-end audio, virtually every pricey product aspires or lays claim to sonic greatness. The truth is that only a very few actually achieve it. With the proviso about the port plugs, the D-5.1 is most certainly one of them. Given that my Magico M Pro/JL Audio Gotham system, which is unquestionably another truly great speaker system, is virtual unobtainium thanks to Magico’s head-scratching decision to severely limit production of the M Pro, the Raidho D-5.1 is even more highly and enthusiastically recommended. At a future date, I will report on the mouth-watering prospect of pairing Raidho’s flagships with the JL Audio Gothams—IMO, the world’s finest subwoofers.

Specs & Pricing

Type: Three-way, ported loudspeaker
Driver complement: One sealed ribbon tweeter, two 100mm diamond midrange drivers, four 160mm diamond bass drivers
Frequency response: 25Hz–50kHz
Impedance: >6 ohm
Sensitivity: 89dB 2.83V/m
Amplification: >50W
Dimensions: 250mm x 1950mm x 680mm
Weight: 165 kg
Price: $225,000 in black; $250,000 in walnut burl; $32,000 to upgrade from the D-5

Raidho Acoustics
c/o Dantax Radio A/S
Bransagervej 15
9490 Pandrup
Denmark
+45 98 24 76 77

JV’s Reference System
Loudspeakers: Magico M Project, Raidho D-5.1, Raidho D-1, Avantgarde Zero 1, MartinLogan CLX, Magnepan .7, Magnepan 1.7, Magnepan 3.7, Magnepan 20.7
Subwoofers: JL Audio Gotham (pair)
Linestage preamps: Soulution 725, CH Precision L1, Constellation Audio Altair II, Audio Research Reference 10, Siltech SAGA System C1, VAC Signature
Phonostage preamps: Soulution 755, Constellation Perseus, Audio Consulting Silver Rock Toroidal, VAC Signature Phono
Power amplifiers: Soulution 711, CH Precision M1, Constellation Hercules II Stereo, Zanden Audio Systems Model 9600, Air Tight ATM-2001, VAC 450iQ, Siltech SAGA System V1/P1, Odyssey Audio Stratos 
Analog sources: Acoustic Signature Invictus/TA-9000, Walker Audio Proscenium Black Diamond Mk V, TW Acustic Black Knight, Continuum Audio Labs Obsidian with Viper tonearm, AMG Viella 12
Tape deck: United Home Audio UHA-Q Phase 12 OPS 
Phono cartridges: Clearaudio Goldfinger Statement, Air Tight Opus-1, Ortofon MC Anna, Ortofon MC A90
Digital source: Berkeley Alpha DAC 2
Cable and interconnect: Crystal Cable Absolute Dream, Synergistic Research Galileo UEF, Ansuz Acoustics Diamond
Power cords: Crystal Cable Absolute Dream, Synergistic Research Galileo UEF, Ansuz Acoustics Diamond
Power conditioner: Synergistic Research Galileo LE
Support systems: Critical Mass Systems MAXXUM and QXK equipment racks and amp stands
Room treatments: Stein Music H2 Harmonizer System, Synergistic Research UEF Acoustic Panels and UEF Acoustic Dots and ART System, Shakti Hallographs (6), Zanden Acoustic panels, A/V Room Services Metu acoustic panels and traps, ASC Tube Traps
Accessories: Symposium Isis and Ultra 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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