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Floor standing loudspeakers

Price: 16 000 zł (pair)

Manufacturer: J.A.F. Jakubas Audio

Kapelanka 5/54 | 30-347 Kraków | Poland
tel.: +48 608 095 884 | +48 122 663 786


Country of origin: Poland


Text: Wojciech Pacuła
Pictures: Wojciech Pacuła
Translation: Krzysztof Kalinkowski

I learnt about the from a review by Marek Dyba, in which he tested their speakers against some others from well known manufacturers, highly praising the Polish construction. Of course, as every review, it needs to be read in a proper context, which in this case are Marek's listening preferences, meaning tube amplifiers, high efficiency loudspeakers, including horns, etc. The review raised my curiousity and I contacted JAF (for the sake of clarity I will quote the name without the dots). I agreed to test their new design, the yet to be constructed Bombard speakers. Then I learnt that their constructor, Mr. Piotr Jakubas, is my neighbor. Not my next door neighbor, but he lives only about two streets away. It only confirms that Krakow is a small city.

The loudspeakers manufactured by JAF are not typical, far from that. That they have high efficiency we already knew from Marek’s test. The model Bombard, the one we are testing now, have an efficiency of 92dB at 8Ω. This is really high. Yet it is not a horn speaker, which could explain this value. Mr. Jakubas came with something else, in his opinion a much better design – a proprietory version of the oldest “patent” in loudspeaker construction – open baffle. Open baffles are usually associated with a large front baffle surface, because this is how they work. That in turn means that they are usually not practical, because they are either too big or, in case they are small, their efficiency is low, especially in terms of bass.
JAF proposes something else – their loudspeakers look like classical constructions (actually better, more interesting) while keeping the assets of an open baffle construction. The solution, already submitted to the Patent Office, is called Smooth Frequency Response (SFR). The idea is to curve the sides of the baffle backwards, so that they almost come together, but leaving a narrow gap between them, going from the top to the bottom. In the company materials we can read that this solution results in low bass with smoothly falling characteristics and minimizes resonances associated with open baffle. So the JAF loudspeakers look different and work different than most other loudspeakers available on the market, while not sacrificing the looks for the idea.
The second thing that makes them stand out is the drivers. In the Bombard we have four wide range speakers HempTone Hemisphere with Hempcone diaphragms. Those are suspended on a classic fold from a textile material. The drivers look similar to Tesla speakers, used among other companies, by the Polish Acuhorn (look HERE and HERE), but Mr. Jakubas quotes their advantages, among them the most important one: a lighter and stiffer membrane with low self-resonance. Those drivers can be used with a simple first order cross-over. In the Bombard a baffle step filter was added. The speakers have a diameter of 210mm and a diaphragm mass around 7.8g and a resonance of 44Hz.
But those are no speakers with a single full-range driver – we have four Hemptone drivers there – working on bass and midrange. And we have a tweeter. This is a Swans ribbon, the RT2PRO, without the front. And this makes sense – ribbons are difficult to integrate with classic cone drivers due to the much higher inertia of the latter (lower “speed”). And full-range drivers with such a light diaphragm are perfect to act as partners with a ribbon.


A selection of recordings used in the test:

  • Abba, Gold. Complete Edition, Polar Music International AB/Universal Music [Japan], UICY-91318/9, 2008, 2 x SHM-CD.
  • Brian Eno, Another Green World, Virgin/Toshiba-EMI Limited, VJCP-68658, 2005, CD.
  • Clan of Xymox, Darkest Hour, Trisol, TRI 419 CD, CD;
  • Depeche Mode, Personal Jesus, Mute/Reprise, 921328-2, 1989, MP CD.
  • Eva Cassidy, Imagine, Hot Records, G2-10075, 2002, CD.
  • Frank Sinatra, Nice’N’Easy, Capitol/Mobile Fidelity, UDCD 790, gold-CD;
  • Gerry Mulligan Quartet, Gerry Mulligan Quartet, Pacific Jazz/EMI Music Japan, TOCJ-90035, HQCD.
  • JS Bach, Six Suites for Unaccompanied Cello, wyk. Yo-Yo Ma, Sony music Entertainment (UK) Ltd/Sony Classical, SM2K89754, 2001, 2 x CD.
  • Madeleine Peyroux, Standing On The Rooftop, EmArcy/Pennywell Productions [Japan], UCCU-1335, CD;
  • Mel Tormé, Mel Tormé Sings Fred Astaire, Bethlehem/JVC, VICJ-61457, K2HD CD.
  • Porcupine Tree, Deadwing, Lava Records, 6793437, CD.
  • The Modern Jazz Quartet, Pyramid, Atlantic/Warner Music Japan, WPCR-25125, 2007, CD.
  • Thom Yorke, The Eraser, XL Records/Warner Music Japan, WPCB-10001, CD;

Japanese versions of the discs are available on CD Japan.

The JAF loudspeakers placed instead of the Harbeth M40.1 show how differently the idea of a loudspeaker built for a tube amplifier can be realized (this is how I see both constructions). This is a completely different sound. It has many similar aspects, but at first sight more things differentiates them than connects them.
I will start with tonal balance. When we take the sound of the Hansen Audio Prince V2 as a reference point in my room, then the Harbeth would have a similar midrange and treble, and JAF would be higher – in the whole spectrum. And they would resemble, almost completely, the tonal balance of my previous loudspeakers Harpia Acoustic Dobermann (New). Bass would be lighter and not as fleshy as from the Hansen, not even mentioning the Harbeth (which have this subrange stronger than it should be compared to “live” sound).
The JAF seem more extended in the top than all the mentioned loudspeakers and resemble what I heard from the German Physiks HRS - 120 Carbon loudspeakers and… the small Monitor Audio Gold GX50 bookshelf speakers. In both cases we do not deal with conventional tweeters but, respectively, a DDD driver and a ribbon. This could explain why the Bombard sound so vivid, in such an unconstrained and open way. The sound of the cymbals, vibraphone or even cello in a large church is very natural in the sense that there is no trace of compression, no impression of information congestion, although we KNOW that there is more information than usual.
I can confirm that they are incredibly fast loudspeakers. They seem to reproduce the impulses, the attack much quicker than many other loudspeakers. Even the Avantgarde Acoustics horn speakers, although exceptional in that aspect, seem to be a bit behind, as if they needed more time to think. Their presentation is almost the same as the JAF, faster than classic constructions, but slightly behind the Krakow built speakers.

This relates to high resolution. It is not as brilliant as from the Harbeth, not even mentioning the Magnepan MG 20.1, but combined with their speed of response and lack of compression it generates exceptional results. The first thing we will notice after plugging the Bombard into the system is the incredible differentiation of the size of the virtual sources, of how close the microphones were in the time of recording, how the sound engineer set things in the mix. And even how the instruments were located vertically. Depending on our previous loudspeakers, it will be either shock or deep amazement. It will never be less moving. The loudspeakers from Mr. Piotr Jakubas are able to reproduce very small elements of the sound, which are usually lost in the system. And – the difference in closeness of the vibraphone of Milt Jackson and the percussion of Conny Kay in the first and third piece from the disc Pyramid is shocking. The same with the cello of Yo-Yo Ma from the disc with Bach suites. In the first case we can hear that in the third track the sound engineer moved the potentiometer and amplified the signal from similarly placed microphones. Because the sound had a similar volume, but in the first track both instruments were quieter. And how well the ability of differentiation can be heard with the cello! Here it seems that the instrument was placed in a similar distance to the microphone, and also here the sound engineer tried to differentiate that. But this time he manipulated the reverb.

Each high class reverb device allows to manipulate many parameters, like decay, pre-echo, etc. Please listen to the first and third track from the second discs Yo-Yo Ma Six Suites for Unaccompanied Cello JS Bach (Sony 2001) and if your system allows it you will hear the work of the last parameter clearly – in the third track the instrument seems much further away from us than in the first. And I am almost sure that they were recorded with identical setting of the microphones and the instrument located in the same place!
I wrote a lot about differentiation, but this is the key element for these loudspeakers. Because this extends also on the bass, and it defines the timbre of the Bombard.
The sound of those loudspeakers seems lighter than the conventional average. The reason for that is that the bass is not as saturated as from other loudspeakers. Its extension is surprising, not only with small ensembles, but also – or maybe above all, because I did not expect it – with electronics, like from the disc The Eraser Thom Yorke. This is an extremely quick sound and this is also – in my opinion – partially the reason for the not so big saturation of the sound, like from my Harbeth. The second part of this puzzle is the lower saturation of the lower midrange than in my system, and here it is the result of using particular drivers. But we get brilliant differentiation – the contrabass will have the size of the contrabass, a bass guitar with an amplifier – the size of that amp, etc. The kick of the bass drum will be dry and short, and the vibrating sound of the Hammond B3 organ will vibrate between the loudspeakers.

Yes – space. This is another very strong asset of the Bombard. Not only will all elements in the counterphase be located to the side or behind us, but we will get nice insight into how the instruments were located in a given recording (this is not about how it was in reality, there are many things that can influence that). They can be close to us or quite far away behind the loudspeakers – everything depends on the size the recording room, the distance to the microphone and the work of the sound engineer. Everything has influence and it all combines into something that the Bombard will show with ease, better than most loudspeakers regardless their price. The instruments will not flow together but each has its individual space. And this is not a result of “cutting” them out (unnatural) from the space – these are not “analytical” loudspeakers, in the sense that they do something artificial to extract the instruments from their background. This process takes place in our heads, we hear everything in a given way and we extract the instruments and their sounds just like we do in a live event – looking at something we hear it clearer, don’t we? Everything depends on what we concentrate upon. The Bombard sound exactly like that.

JAF Bombard + Leben CS-300X [Custom Version]

In addition to the regular test with my reference amplifier, which I use with all the loudspeakers tested, I tried the Bombard with an amplifier that has a chance of playing with them in a real system (the reference amplifiers shows the loudspeakers in a maximally objective way, while others in a context). I am talking about my heavily modified Leben (please read HERE and HERE – this was one of my reader's suggestion and I followed it).
Connecting to a tube amplifier usually brings a certain set of sound changes – for example the output of the amplifier is heavily modified with the impedance curve of the loudspeaker, the peak of the signal is compressed (limited power), etc. Usually the advantages win over the drawbacks. And it was also the case here. With the Leben the extraordinary resolution disappeared, the sound stage was less distinctive and the bass did not reach that far. But everything got more saturated, the midrange got more saturated, more mature. The sound was a bit closer. Most of all it seemed more coherent. It seemed that there are less sounds – for sure – but those remaining had more in common. Earlier the sound was very transparent but a bit light. With the Leben – as I said – the bass was more shallow, not as tight, but its medium and upper range were stronger and more “fleshy”.
In general, this combination proved to be fantastic. Although the manufacturer of the Bombard suggests using amplifier with a power output of more than 20W, my Leben, with 7W per channel, did not have problems in driving the loudspeakers. The volume knob was at “3”, but this did not disturb me at all. Besides, the “factory” version of the amplifier is twice as powerful, so there will be no problem at all.


The JAF Bombard loudspeaker is a floor standing construction, two way, five drivers, in an open baffle in the Smooth Frequency Response (SFR) version. This means that the loudspeakers look similar to classic ones, with a lute shape, as used prominently by Sonus faber (especially with the model Amati Futura). But the cabinet is open on the back – there is a quite wide gap running through the whole height of the loudspeaker. But the cabinet is closed from below and from the top with thick MDF elements.
The cabinet is made from two materials: wood and MDF. The sides are wooden (there are many kinds of wood available), while the front, top and bottom are from MDF, finished with black, matte varnish. The back spike is bolted to the bottom plate, while the front two are bolted to the wooden sides. On the back, on the plate, there are the single wire terminals, mounted vertically. From the top there are plates with the company logo and model name glued in. The whole looks fantastic and is fantastically well made. Bravo!

From the front we can see four full-range drivers and a hole covered with black material with a ribbon tweeter underneath. All speakers were mounted from the back, so we cannot see any bolts. There is no grille. The full-range drivers were manufactured by the HempTone company, this is the model FR 8 (with 8” diameter). Despite the fact that those drivers have a wide range also from the top, due to the small horn on the diaphragm, the constructor supports them with a quick ribbon tweeter, the model RT2PRO from the American (initially Canadian) company Swans Speaker Systems, which was slightly modified by removing its front and bolting it directly to the front baffle. The cross-over is of the first order, but I do not know exactly what elements are in it, because the loudspeaker cannot be dismantled (at least I cannot do it). Looking through the gap we can only see that the bass coil is wound on a toroidal core (probably from Jantzen) and covered with damping material. The high frequency section uses a polypropylene capacitor from Jantzen Audio. The internal cabling is made from a silver plated copper braid with 4mm2 cross-section. The cable from the terminal is copper. A different cable was also used for the ribbon.

The loudspeaker will also be available in a more “beefed up” version. The changes to the basic version are described as follows by Mr. Jakubas:
“The model Bombard is also available in a version with different equipment, usually it can be a different capacitor for the ribbon (from the ones available on the market), different internal cabling (from those available on the market), different wire terminals (for example WBT-0763, WBT 0702, Furutech FP-805, not all of them, because they have to be from a fitting technology) and the main toroidal coil can be of higher conductance than the standard one. The list above actually exhausts the upgrade possibilities. You can also order different side panels, made from other kinds of wood, standard is Merbau. The kind of wood depends on market availability, mainly exotic wood, such as Acajou, Iroko, Nyatoh, Tauari, but also oak or ash. The varnish for the front is free to choose – standard is black structural matte. Each change or departure from the standard is a extra cost. The details are agreed upon individually, depending on the availability of a given option on the Polish market”.

Technical data (according to manufacturer):

Recommended amplifier power: > 20W
Frequency response (-1dB): 38Hz – 22kHz
Frequency response (-3dB): 31Hz – 30kHz
Nominal impedance: 8Ω
Efficiency: 92dB
Baffle width equivalent: 840cm
Dimensions: 1096 x 295 x 356mm
Weight: 34kg (piece)

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  • CD player: Ancient Audio Lektor Air (previous it was Prime, tested HERE)
  • Phono preamplifier: RCM Audio Sensor Prelude IC (tested HERE)
  • Cartridges: Air Tight Supreme, tested HERE, Miyajima Laboratory Waza, tested HERE.
  • Preamplifier: Ayon Audio Polaris III with Re-generator Power Supply; version II tested HERE)
  • Power amplifier: Tenor Audio 175S, tested HERE and Soulution 710
  • Integrated amplifier/headphone amplifier: Leben CS300 XS Custom version (reviewed HERE)
  • Loudspeakers: Harpia Acoustics Dobermann (tested HERE)
  • Headphones: Sennheiser HD800, AKG K701, Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, 600 Ω version (reviewed HERE, HERE, and HERE)
  • Interconnect: CD-preamp: Acrolink Mexcel 7N-DA6300, article HERE), preamp-power amp: Wireworld Platinum Eclipse
  • Speaker cable: Tara Labs Omega Onyx, tested HERE
  • Power cables AC (all equipment): Acrolink Mexcel 7N-PC9300
  • Power conditioning: Gigawatt PF-2 Filtering Power Strip (reviewed HERE)
  • Audio stand Base – under all components
  • Resonance control: Finite Elemente Ceraball under the CD (article HERE)
  • Pro Audio Bono platform under CD