The idea of a speaker driver called “superleggera” was conceived after completing the “improved audio” project [ed. note: it concerns one of development versions of a broadband Acuhorn driver]. The project focused on systematic research to come up with reference sound. The starting point for new designs were various, already tested, ways of mounting speaker drivers in the speaker cabinet. The next step was the search to find a proper kind of wood and various ways of its lamination in order to obtain the right material for speaker cabinets.
The differences are so significant that they make listening to music meaningful. It is what audiophiles like the best, the owners of turntables, super cables and independent 240 V power supply: “better hard than soft, hence metals, plastics, foam, rubber are not good”, but also “too hard – equally bad, all metals ‘ring’ and transform vibrations in their own way”. Other materials damped vibrations in an “unnatural” way, etc. Wood was supposed to be the foundation. In the beginning it was meant to be a wooden box. Acuhorn employs two acoustic chambers. One forms midrange, the other is responsible for bass. I employed the earlier developed, proprietary method of shaping the acoustic wave resulting in precise soundstage and bass response. After initial drawings and considerations it was time to come up with a design. Covering the whole project of a new speakers’ series, I set the PURE direction for the implementation of the acoustic chamber and speaker driver. I wanted a light, no-frills speaker diaphragm, assuming that the only thing that matters is sound. I only kept my neodymium "engine", that is magnets and pole pieces, and the suspension with the diaphragm - a moving mass. And I put it directly into the wooden acoustic chamber. Just as luthiers do it in stringed instruments. They put the strings directly onto the resonant box and support them from the inside with a piece of wood called the sound post or "the soul". Isn’t it a great idea?! The diaphragm rests on the resonant chamber, and the rear suspension on the wood inside, as if on the "soul". The diaphragm and the rear suspension are coupled by wooden components, with vibration only transferred by wood. The end result surprised me - the sound was smooth and detailed at the same time. I have not yet heard such differentiation; moreover, the sound was very textural. Individual sounds now differed more markedly from each other. Arranged in the space, they were tantalizing in their beautiful surface and their shapes and various degrees of coarseness. Praise and thanksgiving to the Creator who has given us wood for our instruments. It's an audiophile acoustic sound dream come true.

No, this is not a treatise of a mad luthier from the 18th century but a technical description of a speaker design sent to me by Wojtek Untershuetz, a designer from Acuhorn, concerning new speakers from the Superleggera series. The name should ring a bell with the lovers of exclusive cars, for they should know Lamborghini Gallardo Superleggera – a tuned up version of Lamborghini Gallardo. As we learn from the description of that car, its lower weight (by 100 kg) combined with 7 kW more power improved 0-100 km/h acceleration time by 0.4 second compared to the standard model. Does not seem much but in the world of hi-end cars it is a lot! The creator of the Superleggera (Italian for ultra-light) is an Italian master Felice Bianchi Anderloni, the designer of car bodies. After Wojtek’s explanations above everything should become clear now: he intended to build a speaker driver with the lightest possible cone which should translate into speed. Hence the name. The reference to Italian tradition is based not only on cars but on violin-makers as well. The cabinets of the new speakers from Gdańsk are a design part of the speaker driver which does not sport a traditional basket any more – the whole cabinet serves that purpose. The proprietary Acuhorn drivers were fully designed in-house.
The speakers are beautifully made; this is high class piece of furniture in the best meaning of the word that just oozes class, class, class. For the review we received the giovane85, the smallest of the series, with a price tag of 3,300 euro (per pair). There are two more models in the series: the acuhorn rosso superiore175 for 9,000 euro and the acuhorn nero125 which will set you back 5,400 euro.

ODSŁUCH

When I once referred to researchers among researchers, specializing in some narrow field, determined to find their own G-spot, with no regard for what is fashionable at the time, what is considered to be proper and what sells well, I meant exactly the kind of product such as the Acuhorn Superleggera Giovane85.
Hooking them up to a classic amplifier such as the Soulution 710, the 530 or, on the other hand, the Arcam FMJ A19, i.e. solid state devices with a high dumping factors and “rigid” power supplies, will be a mistake. The sound emerging from Wojtek Unterschuetz’s speakers will repel everyone regardless of his or her conviction or experience. The sound’s attributes will be flatness, “thinness”, lack of bass or even its reminiscence.
There are various wonders that occur in audio world and even though we are still not able to explain many of them and we base our opinions on conducted experiments and tests, i.e. auditions, we have it ingrained somewhere that this is the right path, that organoleptic tests, personal experience is more important than anything else because in the end it is us who will do the listening, not any measurement systems or theories.
Even then, equipped with this kind of knowledge, we are rendered helpless faced with a change that will take place when we connect the speakers to a tube amplifier, such as the Leben CS-300 XS [Custom Edition] for instance. With a well matched speakers-amplifier pair we will hear something that is generally hard to find in audio, leaving the money issue aside. Let’s list it: internal coherence of all sounds, complete lack of “tension” introduced by the speakers which in turn exposes the emotional tension in music, the way of creating new space in the listening room similar to what the best headphones do, such as the Sennheiser HD800. In a word, it will be thrilling. It will also be beautiful. We will mention PROBLEMS related to this type of presentation as well. First though, let’s talk about the GOOD aspects and how they manifest in music.
The most striking feature of the Giovane85 speakers is creating in almost every case a new reality in the listening room. These are not just instruments, vocals or generally sounds projected in front of us, nicely fitted in the room acoustics where we enjoy the listening experience. The speakers from Gdańsk re-create not only sounds but the whole acoustics that comes with them, the atmosphere of the recording with master-tape noise (if any) in one go, “ductilely”, at once. What we receive is a bubble of new reality very similar to what we hear (I will repeat myself cause it is important) through headphones. The soundstage is as wide as we set the speakers apart and as deep as we deem proper. The latter calls for a short explanation.

Full-range drivers present the depth of soundstage and the depth of a given instrument (its body) in a specific way. When we focus our attention on a whole event it seems then that the soundstage is rather two-dimensional and that the speakers do not differentiate the depth. But when we focus on a specific instrument it becomes real, taking on shape, vividness, body. It bears an uncanny reminiscence of a real life concert experience. Listening to Tomasz Stańko’s trumpet from his Lontano album I had very similar impressions to those I’d had two days earlier, sitting in the Krakow Opera House during his concert with the New York Quartet, at least as far as the spatial aspect was concerned. The concert was a part of a tour promoting his double album Wisława. Let me repeat: general focus equals lack of depth, specific focus introduces depth and reality. It is entirely up to us to decide how we will perceive it and how we decide to focus.

The way the specific sub-ranges are placed in space helps to that end. In classic speaker designs where each driver reproduces a rather narrow frequency range, cut out from the whole spectrum, higher sounds are usually located higher, on the level with the tweeter, no matter how well it is matched with other drivers. We also experience differentiation here but it is on another plane: high frequencies seem to be closer to us, almost tangible. They are not irritating or detached from the rest of the frequency range but the lower we go the further the instrument seems to be. The whole is incredibly fluid, nothing is “torn”; the impression stays, though. It is impossible to hear that anywhere else; only full range speakers are capable of such a feat. They seem to create a sphere extending towards the listener. The whole is smooth and “coherent” but a part of that sphere with the high frequencies is closest to us. In classic speakers, if high frequencies are dominant and the tonal balance is disturbed we simply end up with brighter sound, with strong cymbals and overexposed sibilants – we all know the phenomenon and (I hope) we recognize it as a basic flaw. Not so with the Acuhorns, though we were first exposed to the elements I am writing about (minus overexposed sibilants).

Again, I have to refer to a musical concert. This is how you hear the drums from the distance of about 8 meters. That’s exactly how I heard it, sitting at the above mentioned concert a few rows from Gerald Cleaver’s drum set, and that’s exactly how I remembered it. Incidentally, the speakers brilliantly showed the speed of the instrument, its dynamics. But what was the loudest, the nearest to me, was the cymbals. The reason is obvious to me: the reproduction of the instrument by the reviewed speakers is highly dependent on the way it has been recorded.

The main microphones, apart from the kick drum, are set above the drum kit, and the cymbals are closest to their membranes. It is therefore possible that Wojtek’s speakers simply show spatial relations associated with the distance, and hence the objective size of the instrument as "seen" by the microphones (and they have a tendency to downsize the more distant objects and enlarge those close-up) and not only show the changes of sound level, like classic "boxes" do.

Well then - the matter of space should be clear by now. Another thing to explain is dynamics. I really wanted to avoid repeating the word 'speed' in this review, but it proved impossible – I just did. I wanted to avoid overusing it, as speed is worthless in itself, it must be in some kind of "service", has something "to do", and not exist just for its own sake.
Its effect on the sound, however, cannot be overestimated in this case. The series name immediately suggests the lightning, so to speak. And it really is - you cannot hear any compression resulting from restraining any sub-range, from restraining the whole. Sounds "come to being" in a natural way, not even "immediately" because the phrase suggests the "creating" them. The Acuhorns seem to reproduce sound "beyond" mechanical limits of the speaker driver suspension or its load. It is obvious that this is just an impression resulting from the comparison to classic dynamic speaker drivers, and that "live" sound is even more present and simply just as it should be. Provided there is a good musician, a good instrument and good acoustics. That is how good magnetostats sound; such is the sound of the Radialstrahler omnidirectional speaker from MBL. And of the Acuhorn speaker.

And finally, the third issue, perhaps most difficult to interpret: tonal balance. I'd be a fool if I did not notice the problems we encounter with speakers of this type. However, I’d show even more stupidity if that would be my reason to cross them out at the outset. It's a classic either-or situation where we need to make a clear choice and stick to it; we either "get in" or get out, without looking back any more.
Wojtek’s Giovane85 have clearly less bass than his nero125 and rosso superiore175. Very little happens below some 100 Hz. The size of the enclosure is the culprit here - we wanted a small speaker so we have to bear the consequences. This lack of bass is not annoying, and even completely negligible, if we know what we want and if we devote a moment to proper positioning and/or amplifier selection.
If we know that vocal music is our thing, small ensembles, even electronic music, but rather the Jane-Michel Jarre type than Nine Inch Nails, the Superleggera Giovane85 will be worth our while. But if we listen to a wide spectrum of music, if Wagner is our favourite composer – go look for something else. The Acuhorns do not create large phantom images and lack the high macrodynamics required for proper rendering of a large music ensemble. Overdriven, they lose definition, and “get lost”, falling victim to their own advantages. These are speakers that try to follow even the smallest details, changes of tempo, intonation, and colour. If we feed them with too much heavy-duty information to “process” (after all, it’s a electroacoustic driver), they will “hang up” at a certain level, and we’ll end up hearing less than from classic, multi-driver speaker designs, compressing a large part of the signal.

The sound of the reviewed speakers can be modeled to some extent, moving them closer to the back wall. I would even say that – similarly to the Audio Note speakers – they sound best kept close to the wall, maybe even in the corners of a room. The sound is bigger, stronger, and more full-bodied. This can be reached in a different way, but the amp we use needs to have bass (tone) control. Something we do not come across very often in audiophile devices. Except for the oldest and the very latest designs. Examples of the former are most numerous in Japan. Music lovers from this country are used to the strangest combinations, choices, setups, and are only interested in the end result and not in how it is reached. Hence the cult of horn speakers and full range speaker drivers. It has long been recognized that the latter need some help from the amplifier, and we find many devices equipped with some sort of compensation circuit, boosting bass. It is present for example in my Leben CS-300 XS [Custom Version]. I have already written about it discussing headphones, where a slight 3 dB boost of the low frequencies often adds the needed saturation. So it was with the Acuhorns - even with the +5 dB boost I did not hear any distortion, and the sound was much larger. But it is not only the oldest solutions that will work. I think that the ideal partner for the Acuhorn speakers will be, tada, digital amplifiers, such as the reviewed by me two months ago Devialet D-Premier AIR. For once, its sound will fit perfectly with what the Giovane85 need, and two, that it gives us the option bass control in the digital domain. Paired together, they will provide a combination that is difficult to think about when sober, and which, after listening to it, will be hard to part ways with when sober.

Conclusion

Speakers with full range drivers come as rare as an empathetic politician. But they happen. Their roots go back to the very beginnings of audio and despite the passage of time the idea of feeding the signal directly to the voice coil without the need to split it in the crossover, without the distortion introduced by it (especially phase shifts) proves extremely attractive for some designers, music lovers, and audiophiles. Since nothing is suppressed in this design, the signal flow is very fast. It is aided by the design of the cone suspension, in which the energy is not lost, as in the classic rubber suspension. The cone itself is also ultra-light, and the driver has a high sensitivity. But the problems are equally numerous. Limited frequency range (mainly from the bottom; the Accuhorn driver plays treble surprisingly well and even), limited macrodynamics and low power.
As usual, it will be our problem, not the designer’s; ours, because in the end it is our decision. The Superleggera Giovane85 speakers will help us make it on the large part. They are beautifully made – Wojtek Unterschuetz is a master when it comes to styling and attention to detail (another person with a similar sensibility is Eric Smólski, the owner of Eryk S. Concept http://www.eryksc.com ). He’s simply got good taste and can apply it to his products. He’s also a music lover, which can be heard in all his speaker and amplifier designs. His choices, however, are so special that they may not necessarily coincide with what we expect from listening to music.
Regardless of our decision, we need to know that the smallest Acuhorn speakers communicate with the customer with exceptional ease, bridging the distance between the speakers and us. They present exceptional microdynamics, very good color (in the context of full range speakers of course) and are a true work of art – because that’s how I treat them – for those who are bored with traditional audio. You can’t get bored with them, considering the possible setups with low-watt tube amps and powerful amplifiers operating in Class D. A true chameleon! Or maybe it’s finally been possible to create a contemporary version of what people had already known 100 years ago?

TESTING METHODOLOGY

The testing had a character of an A / B / A comparison with the A and B known. The reference was:

• Harberth M40.1 Domestic stand-mounted speakers on the Acoustic Revive Custom Series Loudspeaker Stands
• PMC GB1i floorstanding speakers
• Dynaudio Confidence C1 Signature stand-mounted speakers Speakers were driven by the following power amplifiers:
• Soulution 710 power amplifier
• Soulution 530 integrated amplifier
• Leben CS-300 XS [Custom Version] integrated amplifier
• Devialet D-Premier AIR integrated amplifier

Music samples were 2 minutes long, whole album were also auditioned. The speakers did not have spikes or stands, however, I decided to decouple them from the ground. I used the Acoustic Revive RST-38 anti-vibration platforms and Finite Elemente CeraPuc spacers with ceramic ball.
The manufacturer suggests placing the speakers in several ways:
1) on two wooden slats in front and rear (the "Japanese" way),
2) on audio stands (anti-vibration platforms)
3) on "spikes" or spacers/pads (not screwed on).
In this case, I also used other than usual speaker cables – speaker terminals located deep and the small weight of the speakers do not allow using thick and heavy cables, such as my Tara Labs Omega Onyx. In such cases, I always use the Acoustic Revive SPC-PA solid-core cables.
The speakers were positioned 1 m from the rear wall, with a bookcase against it, and were directed to the listener's ears with a slight bend to the outside. The work best in small spaces and close to the listening position.

DESIGN

Speakers with a full range driver seem to be very simple designs: one driver, no crossover, just a speaker cabinet. And of course speaker terminals. Problems with a proper design and its implementation are, however, enormous. First of all, one needs to select an appropriate driver. Acuhorn have been experimenting for years with this type of drivers and offers its own proprietary designs, with a paper cone, fabric-made suspension, a small horn reproducing high frequencies and a neodymium magnet. In the speakers of the Superleggera series the designer went even further: the cabinet is actually a part of the speaker driver. The speaker cone with the rear suspension and the magnet is glued to the cabinet in such a way that the front suspension becomes a part of the front baffle. The magnet is supported by a solid metal plate holding it in place. The speaker driver is literally glued into the resonant chamber - there is no trace of screws, driver basket, etc. The front baffle is also the plane of driver front suspension.
The second problem with speakers featuring one full range driver is driver load. Wojtek Unterschuetz prefers horn loading. In large speakers such a solution is much easier because we have a large speaker volume and a large area of the horn mouth. The Giovane85 is, however, tiny by the horn standards – it looks like a classic speaker. Hence, its bass extension is limited. Yet, since the horn mouth is located at the rear, we can adjust the amount of bass to a certain extent, positioning the speaker closer to or further apart from the rear wall. The cabinets are fantastically finished with wood veneer, with open pore painting, and everyone at home liked them a lot. The veneer has been selected in such way that the speakers form a proper pair. At the bottom of the front baffle silver letters were pressed into the baffle, forming the name of the company, and the pink "Superleggera" logo was pressed into the side wall. Everywhere else it would look embarrassing, but here it creates a coherent, simply delicious, whole.
Finally, speaker terminals, the least appreciated speaker component – quite wrongly! The reviewed speakers sport gold plated terminals that look solid. They do not particularly stand out in comparison to other, good terminals. What’s more important is that they are not mounted to the rear wall, but to a baffle forming the horn mouth, and thus inside the speaker. This allowed to almost completely eliminate the cables connecting the driver terminals and speaker terminals.
An interesting fact is the lack of any spikes, spacers, or even sockets into which they could be screwed in.
The speakers look professional, they are beautiful and will be the pride of any interior. Together with a tube amplifier and a turntable, but also the Human Audio Libretto HD http://highfidelity.pl/@main-1447&lang= CD player they will make a system others can only dream of.