Raidho D-5.1

But Wait, There’s More!

Equipment report
Raidho D-5.1
Raidho D-5.1

“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
+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

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