Jamo’s sales pitch for its new high-end speaker begins like this: “Loudspeakers are inherently compromised – because they are based on boxes”.
Jamo R909 | $18,600 |
For: Deep bass and expansive imaging. Easy on the ear and just as easy on the eye thanks to the distinctive and elegant enclosureless design.
Against: Not as sharp or as analytical as some similarly priced models, may be too ‘fruity’ for some tastes. The physical characteristics of the speaker are not for everyone.
Verdict: An individual take on the high-end loudspeaker, the R 909 is relatively easy to integrate into real world systems and rooms, and its proportions look just right (not a given at this end of the market), the shallow depth being especially striking.
The company can comfortably make the above claim because there’s no sign of a box anywhere on the Reference R 909. It is not an especially tall speaker, but it is very wide, and it houses not one but two massive 380mm drivers. The next surprise is the shallow depth of the enclosure. It fact, it doesn’t have an enclosure. It is a flat(ish) baffle loudspeaker, and the bass and midrange section is dipolar (the tweeter is a sealed unit).
So why a dipole? And why feature moving coil drivers when virtually all full-range dipoles use planar diaphragms, such as electrostatics? One answer to the first question is that boxes have problems, namely delayed resonances as the energy is fed into, and then re-radiated after a time delay from the whole of the enclosure. There is also a hysteresis effect resulting from the air inside the enclosure being wound up like a spring by the energy imparted from the back of the drive unit cones. An open baffle arrangement is inherently free, or largely free of these issues. It is still energised by the reaction force from the moving diaphragms, but most of the time delays, the hysteresis effects, do not apply. Jamo claims that dipoles can offer better dynamics, attack and precision – given a properly sorted design. But dipoles couple to the listening room in a quite different way.
The reason for moving coil units is that planar diaphragms are physically incapable of covering low frequencies. This is why most electrostatics are either very large, or hand over the bass to a dedicated moving coil section. Electrostatic or other large area planar drive units also have an intrinsically low voltage sensitivity, and a low load impedance. This means they require a lot of very high quality amplifier horsepower.
A moving coil bass section with stiff, light cones (to minimise delayed resonances) provides a workable solution, but there are still issues to address. The main one is the progressive loss of bass as the high pressure air in front of a forward moving bass cone rushes around the rear of the panel (and vice versa), effectively short circuiting the bass. Nature – as we know – abhors a vacuum. This can be counteracted by a larger baffle, but this would be undesirable for cosmetic reasons. A more promising alternative is to engineer a 6dB/octave bass boost below 200Hz, which is precisely what Jamo has done by including the enormous bass radiating area of two 380mm drivers, a species of drive unit you are otherwise likely to encounter domestically only in a handful of very large subwoofers.
The bass drivers of the R909 are optimised for their role, with lightweight air-cured paper cones with a rubber suspension, for maximum responsiveness, and an open air resonance of 27Hz. This gives the system a LF coverage extending to around 25Hz. The midrange driver is a high-tech SEAS 135mm unit with a magnesium cone and a fixed pole piece to minimise moving mass, to cover the all-important 250Hz-2kHz region. The 25mm tweeter is a customised version of the celebrated Scan-Speak Revelator, but with a smaller face plate so that it can be placed closer to the midrange driver. The crossover is a fairly simple design with 2nd order (12dB/octave) slopes throughout, with quality components including Solen foil caps and air core inductors.
The real killer here, however, is the structure of the speaker. Stability is ensured by a massive and heavyweight base, which extends well forward and behind the baffle. That flat panel is actually a seven-layer, 43mm-thick MDF sandwich, curved back towards the side edges for increased stiffness and to reduce diffraction, and braced by a cleverly designed 5x60mm stainless steel reinforcing brace/damper, which runs from the back of the plinth to the top of the baffle. We were truly amazed at how stiff this speaker is. We expected some flexure near the tweeter, which would have had a critical impact on sound quality. In fact, we’ve rarely encountered a full box-type speaker that moved less when provoked. Or, for that matter, one with a better finish than Jamo’s selection of high-gloss black, red or yellow laquers.
Some may be surprised that a speaker so idiosyncratic has been made by Jamo, but in fact, the company has a good track record in cost no object, state of the art loudspeakers. The R909 simply marks a return to radical form. The original prototype, the brainchild of Jamo’s chief acoustics engineer, Henrik Mortensen, was constructed about eight years ago, but the decision to release it as a commercial product is much more recent, triggered perhaps by the recent takeover of Jamo by Klipsch. Or perhaps not: Jamo claims that the R 909 is a response to increasing demand for high-quality stereo reproduction.
Jamo has not merely made a cover version of what is already available. Its assertion that dipoles don’t interact severely with their surroundings, however, is only partially vindicated. It certainly sounds different in different rooms, but it worked extremely well in my own main room, with the R 909 spaced about two and a half meters apart, toed in by about 25 degrees and placed clear of the corners and walls in a room measuring five meters wide, and at a listening range of about three metres. The tweeter is high up on the baffle, and it is difficult to find a seating position such that the tweeter doesn’t point a little above the ear plane, but that may have been a deliberate design decision. Certainly, the balance is shy in the upper midband through to the high treble, which complements an overall balance that naturally favours the bass over the midrange, albeit only slightly.
The R 909’s voicing tends to be warm and full, with a touch of receding upper frequency content. Complementing this, imagery is broad and deep, but this is not a speaker that offers the holographic, ‘in your lap’ imaging of the best MartinLogans, or some of the more analytical conventional moving coils. In short, this is a speaker with personality. What you get here is an enormous sense of scale, far exceeding conventional speakers, even big ones like B&W’s larger 800 Series models. And yet somehow Jamo has conspired to deliver this scale without any obvious sins of overhang or ‘boom’. The sense of drama, of the physical presence of the musical performers right there in the listening room, appears to be intrinsic, where more conventional speakers with a similar balance often sound overblown.
Jamo claims there is “no cabinet contribution” to the sound, and that the R 909 is “clear and uncoloured”. This is putting it too strongly. As already suggested above, the R 909 is far from being a speaker devoid of the kind of character generally associated with loudspeaker enclosures, but its character is different. From one point of view, the big, easy and relaxed sound of this speaker is one of its greatest strengths, especially as it is achieved without loss of detail, and without sounding ‘blowsy’ or out of control. And this is exactly what the R 909 does achieve. Sure, it is perceptibly warm, but the bass is unusually tuneful and well proportioned in its own right. Orchestral entries are well timed, with the kind of balance and weight you might well be looking for when seated, say, one third to one half of the way to the back of many concert halls; the kind of balance that allows a rich, yet complex sound from the cellos and double basses.
But the Jamo is just as good at the more subtle stuff. Although the Revelator tweeter doesn’t have quite the precision and crystalline purity of a diamond or beryllium tweeter, it is better than most of the rest. In particular, it offers broad and even dispersion, and it’s good at maintaining its voicing at a wide range of different power levels. There is no hint of a change in sound, or of any loss or articulation or clarity during very loud passages, and theR 909 is one of the most adaptable of speakers in that it retains a sense of presence, scale and consistency across a wide volume range.
It is also a speaker which works really well with human voice, female voice in particular. The likes of Madeleine Peyroux, Patricia Barber and Suzannah McCorkle, whose expressive, jazzy lyricism often gets mangled when processed in the high-fidelity machine, come across with a rare beauty, the kind of expressiveness and fluidity often associated with much smaller speakers, and a freedom from chestiness or the usual box type artefacts. But, and this is rare in combination, the R 909 is also a superb instrument for large-scale material in any genre. It worked well, for example, in Schoenberg’s densely scored Pelleas und Melisande (a personal favourite), thanks to its crisp midband, strong overall homogeneity and a sense of weight and extension and that is as rare as it is precious.
On paper, the Jamo R 909 may look like a difficult proposition, but in real life it’s much more forgiving than many of its peers. True, it doesn’t suffer inadequate amps without protest, but it doesn’t require excessive power, just firm control, and it turns out to be easy to place in medium size rooms or larger. It is also an easy loudspeaker to listen to, which is not always the case at this end of the market – it’s sufficiently but not excessively analytical, and its attractive balance is just on the warm side of neutral.