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Reviewer: Kari Nevalainen
Source: EMT 928 and 930; Verdier Nouvelle Platine; Lumiere/Ortofon/Denon cartridges on Ortofon and EMT arms; Audiomeca/Sentec for digital
Preamp/Integrated: Shindo and Marco and various vintage designs; Behringer 1024 digital equalizer
Amp: Shindo Montille EL84 p/p; Marco 6V6 p/p; various vintage designs; Sun Audio 2A3 SET [on loan]; Densen B-330 [on loan]; 200wpc Sony receiver; Plinius 9200 integrated
Speakers: open baffle Phy, Fostex, Seas and Stentorian single-driver designs
Cables: silver-coated copper
Room size: 4.5m x 7m

Review component retail: € 10.000/pr 

When I first saw Jamo's Reference 909 speaker standing nobly in my living room -- like one of the rocks from the Stonehenge ruins, a Bronze Age statue from the Cyclades or a piece of African art - my immediate question to it was: What's your imperfection? How do you propose to manifest the idea of the ideal speaker? What's your special trick? What's your raison d'être?

And as I tried hard to find an answer, I could think of nothing that wouldn't point, somehow or other, back at its dipole bass. The essence of the R909 cannot lie, for instance, in being a planar speaker with all the well-known advantages related to such designs (fewer side-wall reflections, no cabinet-induced resonances etc.). For even though the R909 is a planar speaker, so are all the full-range electrostatics and magnetostatics.

Unlike the latter, the R909 uses dynamic drivers exclusively so how could they be planars? The history of speaker building knows surprisingly many dynamic speakers in which midrange and tweeter are installed in an open baffle -- say the original Dahlquist and its successive Alon by Acarian derivatives -- but when it comes to reproducing the bass frequencies, their woofers are boxed up with finality. So the key to the R909's soul -- the landscape of its mind, what makes it unique --- must ultimately be its dipole, out-of-the-box bass system.

Full-range dynamic dipole speakers are not from another world. The concept is well known and much explored by DIYers here in Finland for instance. In fact Risto Niska, one of my audiophile colleagues, was fed up with the singing of the boxes and their phase nonlinearities so he built himself such a dipole ten years ago and has been happy ever since. No wonder then that when I first showed him pictures of this Jamo, he shrugged them off: "Nothing special!"

I myself have used folded and open-backed baffles of different sorts to house dynamic wide-band units. These differ from the R909 only in being much larger and not using any filter network to correct the frequency response. Commercial models are not that common, though. There's the Linkwitz Orion of course, with Siegfried Linkwitz being the long-time spokesman for full-range dynamic dipole loudspeakers. Perfect 8 has a model called The Force but even they recommend a subwoofer for the bottom octave. BD-Design's Quasar MkII DIY is similar to the Jamo R909 and the Acoustic Plan Veena is yet another one. Legacy Audio's Whisper and the Gradient Revolution are famous for their dipole bass but their midrange drivers are in a cabinet. (Gradient further manufactures dipole subwoofers for Quad 57s and 63s.) Now Jamo, under the supervision of Henrik Green Mortensen, has gone after the idea full hog, nine long years after building up the gumption to do so.

What unites all of the above speakers is their designers' conviction that for the most pure and articulated bass, one should never use a box whether sealed or ported. In fact, it's possible to read the R909's White Paper to imply that getting rid of a box with all the adverse effects that come along with it was the main goal of its design - "to deliver an exceptionally memorable listening experience" the real goal by extension.

With all this initial personal focus on dipole bass, I'm of course not implying that from 200Hz up to 7-8kHz -- the midrange to me -- the R909 would be less interesting. Not only do most of music's fundamental notes reside in this band but also more than 90% of their most important harmonics. No one can convince me otherwise. Some of the 60 to 9.000Hz speakers (not drivers) I've heard impressed me more than 95% of the speakers that do it from 20 to 20.000Hz - or 50.000 or 100.000 even.

Issues to be considered in this context are, however, more conventional in nature, mainly having to do with the quality of the drivers and the way in which they are made to cooperate. These are important questions but not unique. The majority of serious speaker designers and manufacturers today seek development of their speakers through advanced driver technology. In Jamo's case, this is even more understandable given that the drivers meant for conventional box speakers cannot as such be fitted into a box-less dipole speaker, most especially the woofers. Custom units were called for.

The tweeter of the R909 is the acclaimed ScanSpeak Revelator. This one-inch multi-coated textile dome has been modified in order to match its output with that of the midrange driver
by fitting a smaller cast-alloy face plate than the stock Revelator employs. Better phase coherence, lower distortion and improved resonance control are further improvements that Jamo has sought with its modifications.

As a consequence, the white paper claims, the HF region of the 909 has "an incredibly smooth, linear, dynamic and incredibly transparent sound". I quote the white paper here verbatim because throughout this review I want to take its sentences as reflecting truth, not mere marketing mumbo-jumbo. That is, I'm going to have a serious dialogue with this material. I think this speaker deserves it.

Naturally, taking sentences seriously is not believing them blindly without questioning. I sure did perform my own tests. To begin with, I asked the tweeter to produce some bird singing, applauding hand clapping, the tuning sounds of an orchestra and related sounds rich with non-harmonic overtones. You may laugh at these test tracks but such sounds do in fact make for a rude awakening if a tweeter isn't well thought out. The Jamo's Revelator handled itself with honors. The quality of the tweeter was noticeable from the very beginning, with no nasty sounds sticking to one's ear as I think one has a right to expect from a speaker of this caliber.

I also pushed the tweeter with Teleman's Flute Fantasias, Purcell's Sonatas and various period music to further test its mettle. All these records contain sounds that can be challenging to tweeters. The flute or recorder for example produces low-level whistling sounds that should be audible but never become unpleasant sibilants. Unpleasant sibilants weren't a problem of the R909. The fact that the speaker's response extends fairly low helps here too as the subjective aggressiveness of certain HF sounds is partially a function of overall tonal balance.

Also, I found the midrange/tweeter transition pretty well realized. Don't expect the conventional problems of
scrappy unevenness on either side of the 2kHz crossover. The fact that the speaker doesn't make this crossing even a minor issue with music such as Schubert's Die Nacht [Robert Shaw Chamber Singers, Telarc] says a lot. It suggests inter alia that many hours of carefree music listening are to be expected. To achieve this level of seamlessness has probably required many nights from Jamo's listening jury. Finally, auditioning the R909 off-axis and from another room indicated no bad directivity jumps moving from the midrange to the highest octaves.

All in all, the quote "an incredibly smooth, linear, dynamic and incredibly transparent sound" gets 4 points out of 5 for factual veracity. The reason for not 5 points is simply that 'incredibly' does not add anything useful (incredibly linear is no more linear than linear). Secondly 'transparency', at least to me, is primarily a property of the soundstage (how tangible it is) and not of any tweeter's performance. (Treble prominence is sometimes taken as extra transparency but that's a mistake and I don't think Jamo believes it either.) One more thing. I have refrained from saying anything positive about the tweeter's tone color - the reason being that excellence from lack of negatives seems to be one of this speaker's core qualities. So I leave it at that.

Both the cone and the basket of the 5.5"/150mm SEAS midrange unit are made of magnesium. The former because magnesium means stiffness and lower weight, thanks to which the driver is said to suffer less cone breakup and intermodulation distortion. The latter because magnesium's strength enables a very open basket for high air flow behind the cone. The magnet employs several compact neodymium magnets placed around the voice coil improving, according to Jamo, voice coil ventilation and heat dissipation. However, Jamo seems most proud of the unit's solid brass phase plug that is said to bestow
several distinct advantages such as improved linearity and greater power handling.

The white paper asserts that the R909 has "extremely low distortion throughout the midrange plus a very open and detailed midrange for optimum voice reproduction". I have neither a dissenting nor assenting opinion on the distortion part of the claim (hard to confirm by ear except on a very general level) but as to the rest, I have this to add. There was a certain forwardness to the sound in a fairly narrow frequency band. By forwardness I mean excessive energy like a discharge, with some notes popping up relative to their neighbors - and those notes were most definitely not coming from the woofers. This wasn't constantly audible but when the music hit the right button, it was present. I would have probably ignored the matter had I not had the chance to audition the speaker in two different rooms. As I paid attention to it in both places I became confident that I wasn't imagining it. Interestingly enough, I found this phenomenon to be most critical on vocals. If this quality then is what Jamo references above by "very open", then for my taste at least, a simple 'open' would have been sufficient. If there's anything in this speaker that can cause possible listening fatigue, it would be this character. It is in no way dominant however on the overall picture.

My other comment could be subject to an extended anecdote. I once had the opportunity, lasting for several years in fact, to use the famous two-way Jamo Concert 8 as a reference, to which I promptly compared all other speakers on the market apart from the most expensive ones. Despite its somewhat controversial upper midrange/treble performance, Jamo's Concert 8 clearly merited its reference status. There's one feature I'll probably never forget, namely how the lower midrange from roughly 200 - 500Hz was executed: it was pure, lean, flat and skinny like nothing else. In some sense, the Concert 8 made all other speakers -- and I do mean all -- sound excessive or fat in that region. It really was that well articulated and polished. I personally liked the feature not least because it supported the music I mostly listened to, i.e. music that doesn't yearn for extra assistance from the speaker's lower midrange register (cello, piano, female voice). Nevertheless, this characteristic proved so overwhelming in the end that although I always considered the Concert 8 one of the good guys, I started to doubt that all other speakers could get it wrong and only this little Jamo right.

Be that as it may have been, I was glad to notice that Jamo had held tight to this character in their new R909 although perhaps not to the same extreme extent as with the Concert 8. This quality makes the sound grey in color and dry in texture. This is easily verified with piano music. If piano is the only instrument you care about and you expect the speaker to reproduce your piano recordings with shine and elevated elegance, the R909 isn't the answer.

Due to this character, the speaker can also take to sounding somewhat brassy and coarse. This happens when no lower midrange frequencies are present, when the instruments in question have a nasty, aggressive timbre and -- this is important because it very much pertains to the 909 -- no artificial reverberations are provided by the room. But note, harsh and nasty is exactly how a speaker should sound under those conditions. A pure and flat lower midrange may not appear to be a big achievement but only after having heard a truly clean lower midrange does one become aware that this property is by no means ubiquitous even in otherwise competent speakers. If this quality of the midrange is what Jamo means by "precise" then I cannot but agree wholeheartedly. If they refer to something else altogether, then I'm out of the loop.

The same white paper further describes the sound of the midrange as "highly effective and dynamic ..." and "subjectively fast". I do however prefer to deal with the issue of speed and dynamics in the context of the speakers' bass performance so onward ho.

The basics of this design, as you recall, are its dipole bass. The dipole bass means that the woofers are radiating the sound freely in both directions, forward and backward. From a bird's eye view, the radiation pattern looks like a figure eight. Many things are to be considered in this connection but the by far most urgent problem inherent to all dipolar designs -- whether dynamic, electrostatic or other -- is how to overcome the weak bass performance due to acoustic short-circuiting. That is, how to prevent the out-of-phase wave forms from canceling each other.

The frequency at which the short-circuiting will start to curtail the woofers' performance at 6dB/octave depends on baffle width. In the R909's case, that's ca. 50cm, with the turning point close to 500Hz but in full effect below 200Hz. This decrease of bass energy must be somehow compensated for. The most intuitive way to counteract this trend would be to increase baffle size. However, to extend frequency response to 30Hz, never mind 20, the surface area of the baffle would have to be larger than a ping-pong table! Utterly useless for all commercial purposes. The most common remedy is to use a passive or active bass filter to boost the lowest octaves.

Jamo's tactic has been to choose woofers that are efficient enough and sport a sufficiently low self resonance. Twin 15-inchers per side equate to the air displacement potential of six 8-inchers or >100dB/1m @ 200Hz according to Jamo. Next, the top end of the woofer spectrum around 250Hz has been low-pass filtered at 12dB/octave to couple with the midrange while leaving the lowest frequencies untouched. This takes care of dipole correction and allows the response to reach the 25-30Hz range with sufficient output.

The woofers are specially developed for this open-baffle application. They sport a lightweight air-dried paper cone with rubber suspension and a sturdy, open-construction magnesium basket. The magnet itself features a vented pole piece as well as a ventilated basket behind the spider.

An aside on listening circumstances. The first room was 4.5m x 6m. It opens up to adjacent rooms and is not easily pressurized nor does it suffer obvious room resonances. The other room was 4m x 7m with carefully chosen reverberation times, a lowered ceiling still at 3.5m and a Helmholtz-resonator behind the listener. In both rooms, I followed Jamo's instructions about speaker placement to a fault: 3 feet from the back wall, 4 from the side wall (the actual distance in both rooms was a little less than this recommendation), and angled slightly towards the listener. This configuration worked surprisingly well - no noticeable music-robbing colorations in either room, no headaches. The speaker seemed to interact fairly easily with a room, almost too easily. In terms of speaker placement, this speaker must have been one of the happiest I've gotten on review in a long time - or I was plain lucky!

Some people argue that dipoles perform sensibly only if they can be dragged at least 2 meters from the wall behind them and there's sufficient space left behind the listener's back. But even if that were the best scenario, far less is adequate too. I have heard similar dipoles such as this Jamo work well with as little as 60 - 80cm behind their backs though no closer as then the reflected sound from the back wall will start to cancel the bass. Naturally, each room is different. The white paper claims that it's still not perfectly understood how dipole speakers interact with the room. I heartily second that as well.

Much has been made of a dipole's rear radiation - how it makes the sound too big and spacious, how it obscures image specificity and so on. The sound reflecting off the back wall can be controlled and the reflections tamed by trying different angles as per Jamo's suggestions. My listening notes do not contain complaints about soundstage and imaging but that may be because I'm accustomed to such a big and relaxed sound from my PHY open baffles above. The sound images weren't sharp-edged in the audiophile sense nor were they unintelligible or diffuse. These things are largely a matter of taste. Open-backed baffle speakers can be critical of incident angle, so it's always worthwhile to experiment.

I asked Jamo about amplification and got a list of brands that probably would work well with their R909: "Mark Levinson, McIntosh, Krell, Holfi, Accuphase - the bigger the better. No digital amps, thank you." I used my 200wpc MidFi Sony and equally powerful Plinius 9200 integrated. Just for curiosity, I tried my 10wpc 6V6 amp too and was amazed by how well the tubes did on these 86 - 88dB panels. In the end, I did switch back to the transistors not only because I felt that the valve advantages in the midrange were not sufficient to offset the lack of control in bass, but because throughout listening to the R909, I got this impression that its sound policy operates on a macro rather than micro level. Discrete differences in the tone color between various amps aren't a matter of life and death with this speaker. The sound is not transparent in that sense.

The same goes for cabling. Jamo recommended Audioquest and Nordost. In addition to my usual arsenal (PHY, Kimber, Chord etc.) I tested Nordost Freys and Hovland Generation 3 and Reference. Both did contribute something to the sound but they would have done so in any speaker setup is my guess. And now for the sound. Jamo's first goal was "to have deep bass but not at the expense of fat, wobbly bass". That verdict is easy. The 909 attains its goal by a wide margin! The bass is deep and low. No organ record I tried suffered from lack of body or energy at the lowest frequencies. And the bass mostly lacked those distracting qualities we so often hear from cabinet speakers of any kind. This is exactly where dipole speakers excel - pure, clean and melodic bass notes. Try organ chorals or suitably recorded harp music or vocal music recorded in a church and imagine how speaker setups can get confused by the bouncing and crisscrossing echoes. Then listen to Jamo's R909. Is it most seductive bass on earth? Probably not but it could be a very credible candidate. I'm not even sure if it's possible to get fat and wobbly bass from a dipole.

Slam? Maybe not in a conventional sense of the word but the kicks department isn't weak either. There's power and punch
but its nature is different. It's politically sound -- correct? -- and diplomatically polite kicking. Nevertheless, the R909's bass has a profoundly he-man character, not the gentleman's version as some other dipoles I've heard espoused.

When listening to good dipole bass, one begins to question whether one has ever really heard proper bass before. Thousands of audiophiles (me included) have probably used the Mission Impossible sound track to impress visitors with. How many of them have heard the bass as it was recorded? If you have doubts, try the 909. If the truth hurts, you can always resort to the common reaction. I can assure you that once you experience quality dipole bass, it's hard to go back to boxed bass regardless of whether one otherwise likes dipoles or not.

Too much bass? I'm sure people who mainly listen to studio productions with electric bass guitar in the main role or in which electronic devices produce unnaturally low bass -- and who are audiophiles enough -- could argue that the R909's low-to-mid bass is plentiful or something to that effect. But let's be careful. Once again, dipole bass is unlike boxed bass: even when excessive, its appearance is not what we would normally expect from a box speaker. When listening to music, the R909 does not force the listener to focus on its bass in a way many box speakers do. When the low bass of R909 gushes forth -- and it does with Chris Jones for example -- one cannot criticize it by normal standards. My favorite test for the nature of the bass is Vivaldi's sonata for cello and basso continuo. Poor bass reproduction here resembles cheap headphones. While the R909 did add extra growl to the cello and basses, it wasn't excessive in the least.

Jamo's second goal for the bass proves no less important: to retain "midrange clarity". It's not trivial to have one with the other. One of the features I very much liked on the R909s was that whenever the woofers were not asked to participate, they kept their voices shut - and ditto for the flat and clean lower midrange I talked about earlier. As a result of this, the R909 can sound a scale smaller than its physical size indicates. Rebel's Les Elements made me laugh because the R909 managed to sound like a 2-way mini monitor. I explored midrange clarity with acoustic solo guitar, simple male vocals, female Jazz vocals with double bass, Vivaldi bassoon concertos, piano music while observing left-handed action - i.e. with music that contains mid-to-upper bass frequencies and might display imbalances between the bass and lower midrange and colorations imposed by the woofers. Very rarely did I have reason to wish for something other than the woofers provided. What's important too is that the quality of the sound remained even when moving from the bass register to the midrange. This is one of the clear advantages of using dynamic drivers throughout, i.e. avoiding hybrid solutions.

Another potential source for midrange colorations is the baffle itself. Jamo's baffle is well prepared for such threats. It's 1.7in/43mm thick, made of seven layers of MDF board and attached to a 60lb/26kg cast-iron base. A solid double 5x60mm stainless steel brace with a special damper keeps the baffle connected to the base. Each 909 weighs almost 70kg each. I didn't hear any acoustic energy around the speakers that I would associate with resonating baffles.

Lastly, Jamo describes the R909 as a speaker capable of delivering "extremely fast and firm bass" with "fast acceleration and deceleration of sounds" and "unmatched precision and attack". This indeed refers to the single most impressive character of these speakers! The way in which bass notes stop when they stop and start when they start is nothing short of fabulous! Take Oscar Peterson's The Paris Concert and listen to Niels-Henning Orsted Pedersen's contrabass. There's only one speaker I know that's comparable in this regard and that is the PHY 12" wide-bander in a large baffle.

The speed of the sound, good timing and great attacks (e.g. on lute music) are not solely attributes of the bass section but characterize the whole speaker. Piano music as with some Schubert's Impromptus recordings turned out to be a good measure of just how explosive the sound of the 909 can be as well as how it scales dynamics. Schnittke's Gogol Suite [Pope Music] is an excellent test of macro dynamics. Very few speaker systems can, at one fixed volume level, do justice to both the cimbalom playing alone and the massive orchestra. The R909's performance here was perhaps not the very best I've heard in my audiophile career but certainly one of the best.

The Jamo Reference 909 is also not choosy with music. It doesn't favor a style or genre at the expense of another. It doesn't have what is often called a personal sound. Its aim is to have an impartial sound that embraces any and all music and plays it securely and enjoyably. Some speakers prefer to be euphonic
with a narrower selection of appropriate music material but not the R909. Anna Muffo's singing on RCA Living Stereo's Turandot never becomes as dramatic and heartbreaking as it perhaps could be but the orchestra is splendidly presented. Of course, the R909 necessarily favors some type of music by not favoring any particular styles. That's the price every universal speaker has to pay for being universal.

Jamo concludes: "It is a speaker that produces a sound quality which can be described as being firm, accurate but with sublime attack, precision and dynamics. Significantly, it also benefits from the absolute absence of unwanted coloration and reverberation." I sign most of that to varying degrees, with a huge Yes going to sublime attacks and dynamics. Note how the word 'music' isn't mentioned anywhere. It would be too hasty a judgment that music means nothing to Jamo but I think leaving the word out of this picture tells us about Jamo's preference to offer to music lovers a platform that will play back any music they happen to like.

Of course each of us has his or her own favorites. My favorites -- the sort of chamber and contemporary music that is light in sound but heavy in substance -- worked fine over the Jamos, albeit sans the special treatment my personal reference system provides. But it didn't fail either and that's a good sign. In addition, the Jamos' strong and authoritative sound made me feel like playing some unlikely personal choices such as certain choral and orchestral works I enjoy far too infrequently (Rachmaninov's Piano Concertos sounded majestic).

There's one aspect of the sound that I think would deserve more attention than I'm able or competent to give here. That's how the sound of the R909's dipole bass (or that of any other dynamic dipole speaker for that matter) translates to music. HiFi literature is filled with many deserving descriptions of how dipole bass sounds in comparison to its boxed competitors yet I haven't seen much written on what that all means in terms of music. It's not proper to state that dipole bass sounds great if there's no musical counterpart to that greatness.

Is the Reference 909 worth its 10,000 Euros (ca. US $12,000)? I'm not sure I relate to the question. Is there a fixed amount or type of sound quality, technical performance, cosmetics etc. that one should get for a fixed amount of money, with a product otherwise not worth the expense? If there was a speaker that looked exactly like this Jamo, sounded like it and technically measured like it yet only cost 5000 Euros, then the R909 would not be worth its present price. But there isn't. Sure, that's a lot of money and were the R909 available for half its princely sum, I'd raise my hat even higher. But the R909 has its price and that's that.

In many respects, this is a big speaker, just not physically because the R909's sculptured outlooks strike a nice balance between audiophile aesthetics and home décor needs. I don't think it's a perfect speaker generally speaking but it comes very close to being perfect given the goals set for its performance. In a curious way, this Jamo Reference 909 falls
somewhere between not being the ultimate speaker for absolute music lovers -- melomanes -- nor being the ultimate speaker for absolute sound lovers, i.e. audiophiles. Yet it could be the ultimate speaker for passionate music listeners whose only concern about the sound is that the music is reproduced at a very high level. Which it unquestionably is...
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